High environmental temperature around farrowing induced heat stress in crated sows

Seasonal effect on farrowing duration in sows within a temporarily confined farrowing system under tropical climates

Global warming negatively impacts sow reproduction, leading to health and welfare challenges and economic losses in the swine industry. The present study was a retrospective observational study that examined the effects of season, temperature, and humidity during parturition on farrowing duration and piglet birth intervals in sows housed in a temporarily confined system under a tropical climate. Data from 10039 farrowings of Landrace × Yorkshire sows (January-December 2023) included parity, farrowing date, parturition onset, total number of piglets born per litter (TB), number of piglets born alive per litter (BA), percentage of stillbirths (SB) and mummified fetuses (MF), and farrowing house temperature and humidity. The temperature-humidity index (THI) and averages for the 7 days before and on the day of farrowing were also calculated. The association between these parameters and the farrowing duration of sows was analyzed. Additionally, the proportion of sows experiencing prolonged farrowing (i.e., >300 min) associated with different factors were evaluated. On average, TB, BA, SB, and MF were 13.9 ± 3.6, 12.4 ± 3.9, 5.7 %, and 5.8 %, respectively. The average farrowing duration was 228.9 ± 194.8 min, with 21.1 % of sows experiencing prolonged farrowing (≥300 min). Dystocia occurred in 5.1 % of farrowings, and the average birth interval for each piglet was 18.7 ± 26.7 min. During the 7-day period before parturition, sows were exposed to an average barn temperature of 26.7 ± 1.9 °C, with daily minimum and maximum temperatures of 25.1 ± 2.2 °C and 29.9 ± 1.0 °C, respectively. The average barn humidity during the 7-day period before parturition was 80.2 ± 5.8 %, with values ranging from 62.1 % to 90.1 %. The farrowing duration of sows was positively correlated with average temperature (r = 0.044, P < 0.001), maximum temperature (r = 0.051, P < 0.001) and minimum temperature (r = 0.057, P < 0.001) during the 7-day period before farrowing. Moreover, every 10 % increase in relative humidity during the 7-day period before parturition caused an increase in the farrowing duration of 21 min (farrowing duration = 61.0 + (2.1 × humidity), P < 0.001). Every 1 °C increase in the average temperature during the 7-day period before parturition caused an increase in the farrowing duration of 4.3 min (farrowing duration = 113.49 + (4.3 × temperature), P < 0.001). In conclusion, 21.1 % of sows in tropical climates experience prolonged farrowing durations. Elevated temperatures, humidity, and THI during the 7 days prior to farrowing or on the day of farrowing significantly extended farrowing durations and birth intervals in sows. These findings highlight the critical importance of maintaining temperature and humidity levels as close as possible to the optimal range for lactating sows (i.e., 12-22 °C), particularly in tropical regions.

Effects of dietary mineral level and creep feed provision on lactating sows during heat stress

This study evaluated the interactive effect of mineral levels and creep feed provision (CF) on reproductive performance, stress level, and immune status of lactating sows during heat stress (HS). 2 × 2 factorial arrangement was assessed, involving two mineral levels (STD, the diet contains 20, 100, 80, 25, and 0.15 ppm of Cu, Zn, Fe, Mn, and Se, respectively; ADV, the diet contains 25, 150, 160, 50, and 0.30 ppm of Cu, Zn, Fe, Mn, and Se, respectively) with or without CF during HS. The CF group showed lower (P < 0.05) respiratory rate on days 8, 10, 11, and 14. ADV and CF groups showed lower (P < 0.05) body weight loss during lactation. A tendency for decreased (P = 0.063) loss of back fat thickness in the CF group. ADV group shows higher (P < 0.05) weaned piglet weight and survivability. CF group showed lower hair cortisol concentration (P < 0.05) with higher (P < 0.05) piglet survivability. ADV and CF groups showed lower (P < 0.05) serum TNF-α level, also increased (P < 0.05) superoxide dismutase and malondialdehyde levels. In milk, the level of Fe, Mn, and Se increased (P < 0.05) in the ADV group. Also, feces excreted higher (P < 0.05) Zn, Fe, Mn, and Se. In conclusion, while both ADV and CF had beneficial effects, ADV posed a risk of increased mineral excretion. Given stricter regulations on dietary trace minerals, CF could be an effective strategy to enhance the performance of sows and piglets under HS.

The parturition-relevant hormone profile in hyper-prolific sows under different housing conditions

Aim was to characterize birth-relevant hormone profiles of reproductively productive hybrid sows in the peripartum period. It was examined whether there are deviations in the hormone profile depending on the birth process (eutocia:dystocia) and the type of housing (box stall BS vs. farrowing pen FP vs. group housing GH).A total of 40 healthy, heavily pregnant hybrid sows (German Landrace x Large White) with a gestation number≥ 2 were available. The distribution between the housing types was: BS n=18, FP n=15, GH n=7. All births occurred after the biologically completed gestation period. Blood samples were taken via indwelling catheters (113th day ante partum to 4th day post partum). Progesterone (P4), oestradiol (E2), prostaglandin F2α and its metabolites (PGFM), relaxin, oxytocin, cortisol, adrenaline and noradrenaline were determined.The ratio of eutocia:dystocia was 15:25. Dystocia occurred regardless of type of housing. The only reason for dystocia was a weak labor (>60 min). The litter size was 17.73± 3.85 piglets. Differences in the hormone profiles between eutocia and dystocia were as follows: P4 tended to be higher in dystocia p=0.0776; oxytocin higher in eutocia (not significant), 12.5% of sows permanently with hypoxytocinemia; cortisol p=0.0503; noradrenaline p=0.0098. The type of housing had the following influence on the hormone profile: P4 p=0.046; E2 p=0.0009; PGFM p=0.0108; relaxin p=0.0022; noradrenaline p=0.0078.The parturition-relevant hormones are related to the parturition and to the type of housing during birth. The hormone profiles obtained could be of use in the discussion about the animal welfare-oriented housing system in the peripartum phase in pigs. The proportion of sows of the hyperproliferative line studied with permanent hypoxytocinaemia in stage II of parturition is remarkable. The ratio of eutocia:dystocia is unevenly distributed. Dystocia occurred regardless of the type of housing.

Sow reproductive disorders: a key issue affecting the pig industry

Pig farming is essential to global agricultural economies and food security. However, reproductive disorders in sows significantly impact the economic viability and sustainability of the pig industry. These disorders often result from complex interactions between pathogenic and non-pathogenic factors. Preventing abortions is typically more cost-effective than managing and treating them, particularly in intensive pig farming system. This highlights the importance of comprehensively understanding the underlying causes of abortion in sows. This review explores the factors contributing to sow reproductive disorders, including both non-infectious factors (environmental conditions and management practices) and infectious factors (viruses, bacteria, and parasites). We also outline preventive and control strategies, alongside integrated management approaches, by analyzing the underlying causes and pathogenic mechanisms of pregnancy disorders. Overall, implementing the "One Health" concept in large-scale farming provides an effective strategy to reduce the incidence of sow abortion rate, ensure stable livestock production, and maintain a reliable global pork supply.

Effects of Dietary Net Energy Concentration on Reproductive Performance, Immune Function, Milk Composition, and Gut Microbiota in Primiparous Lactating Sows

This study aimed to determine the optimal dietary net energy concentration for the reproductive performance, immune function, milk composition, and gut microbiota of primiparous sows during lactation. Forty primiparous lactating sows (Landrace × Yorkshire) with similar body backfat thicknesses were randomly allocated into five treatment groups and fed diets with different dietary net energy concentrations of 10.05 MJ/kg, 10.47 MJ/kg, 10.89 MJ/kg, 11.30 MJ/kg, and 11.72 MJ/kg. The results showed that there were no differences in the performance of piglets, while there was a decrease in the daily feed intake of sows (p = 0.079, linear) as dietary net energy concentration increased. With the increasing dietary net energy concentration, the plasma insulin levels of sows increased (p < 0.01, linear), the plasma glucose levels tended to increase (p = 0.074, linear), and the blood urea nitrogen levels tended to decrease (p = 0.063, linear). Moreover, the plasma total superoxide dismutase activity of sows increased (p < 0.05, quadratic) and the plasma malondialdehyde content of sows decreased (p < 0.05, quadratic) by increasing the dietary net energy concentration. Interestingly, with the increase in dietary net energy concentration, the plasma immunoglobulin M content of sows increased, the milk immunoglobulin M, immunoglobulin G, immunoglobulin A and the percentage of milk fat increased (p < 0.05, linear), and the milk secretory immunoglobulin A content also increased (p < 0.05, linear and quadratic). The milk immunoglobulins and milk fat content of sows fed with net energy concentration of 11.72 MJ/kg were highest. Moreover, there were significant differences in the α-diversity, β-diversity, and relative abundance of gut microbiota in sows fed with different dietary net energy concentrations. At the phylum level, Spirochaetota and Bacteroidota in the gut microbiota of sows were mainly affected by increasing the dietary net energy concentration. Furthermore, the correlation analysis showed that milk immunoglobulin content had a significant negative correlation with the relative abundance of Bacteroidota, and plasma malondialdehyde content also had a significant negative correlation with the relative abundance of Spirochaetota. In summary, these results suggest that increasing the dietary net energy concentration to 11.72 MJ/kg can increase immunological substances in milk, improve milk quality, and alter the composition of gut microbiota in primiparous lactating sows.

Artificial intelligence and porcine breeding

Livestock management is evolving into a new era, characterized by the analysis of vast quantities of data (Big Data) collected from both traditional breeding methods and new technologies such as sensors, automated monitoring system, and advanced analytics. Artificial intelligence (A-In), which refers to the capability of machines to mimic human intelligence, including subfields like machine learning and deep learning, is playing a pivotal role in this transformation. A wide array of A-In techniques, successfully employed in various industrial and scientific contexts, are now being integrated into mainstream livestock management practices. In the case of swine breeding, while traditional methods have yielded considerable success, the increasing amount of information requires the adoption of new technologies such as A-In to drive productivity, enhance animal welfare, and reduce environmental impact. Current findings suggest that these techniques have the potential to match or exceed the performance of traditional methods, often being more scalable in terms of efficiency and sustainability within the breeding industry. This review provides insights into the application of A-In in porcine breeding, from the perspectives of both sows (including welfare and reproductive management) and boars (including semen quality and health), and explores new approaches which are already being applied in other species.

Accurate models and nutritional strategies for specific oxidative stress factors: Does the dose matter in swine production?

Oxidative stress has been associated with a number of physiological problems in swine, including reduced production efficiency. Recently, although there has been increased research into regulatory mechanisms and antioxidant strategies in relation to oxidative stress-induced pig production, it remains so far largely unsuccessful to develop accurate models and nutritional strategies for specific oxidative stress factors. Here, we discuss the dose and dose intensity of the causes of oxidative stress involving physiological, environmental and dietary factors, recent research models and the antioxidant strategies to provide theoretical guidance for future oxidative stress research in swine.

Factors associated with farrowing assistance in hyperprolific sows

OBJECTIVE

The present study was performed to determine risk factors associated with the frequency of farrowing assistance in hyperprolific sows in a tropical environment and to investigate the impacts of farrowing assistance on piglet colostrum consumption and sow colostrum yield.

METHODS

Farrowing data from 352 Landrace×Yorkshire crossbred sows and 5,554 piglets in five commercial swine herds in Thailand were investigated. The sows were classified according to parity numbers: 1 (n = 72), 2 to 4 (n = 128), 5 to 6 (n = 84), and ≥7 (n = 68) and the total number of piglets born per litter (TB): 10 to 13 (n = 90), 14 to 16 (n = 117), and ≥17 (n = 145). The incidence of farrowing assistance and associated parameters were investigated.

RESULTS

The TB and farrowing duration averaged 15.8±0.2 and 279.9±11.2 min, respectively. The percentage of sows that required farrowing assistance was 29.8% and varied among herds from 5.7% to 53.3% (p<0.001). The percentage of piglets born after birth assistance using manual intervention was 8.4%. Sows with parity numbers 1 and 2 to 4 had a lower frequency of farrowing assistance than sows with parity numbers ≥7 (p<0.01). The colostrum yield of sows that required farrowing assistance did not differ from sows that farrowed without assistance (5.3±0.2 and 5.1±0.1 kg; p = 0.288); however, the colostrum consumption of piglets born from sows that required farrowing assistance was lower than those born from sows that farrowed without assistance (302.2±15.7 and 354.2±5.6 g; p<0.001). Blood oxygen saturation of the piglets born after birth assistance tended to be lower than the piglets that farrowed without birth assistance (87.8%±1.3% vs 90.4%±0.4%; p = 0.054).

CONCLUSION

The frequency of farrowing assistance in sows varied among herds and was influenced by parity number. The piglets born after receiving birth assistance should receive special care to improve their blood oxygen saturation and enhance colostrum intake.

Maternal tributyrin supplementation in late pregnancy and lactation improves offspring immunity, gut microbiota, and diarrhea rate in a sow model

Introduction

Several studies have evaluated the effects of tributyrin on sow reproductive performance; however, none of these studies have investigated the effects of tributyrin on sow gut microbiota and its potential interactions with immune systems and milk composition. Therefore, we speculated that tributyrin, the combination of butyrate and mono-butyrin without odor, would reach the hindgut and affect the intestinal microbiota composition and play a better role in regulating sow reproductive performance, gut flora, and health.

Methods

Thirty sows (Landrace × Yorkshire) were randomly divided into two groups: the control group (CON) and the tributyrin group (TB), which received basal diet supplemented with 0.05% tributyrin. The experimental period lasted for 35 days from late pregnancy to lactation.

Results

The results showed that TB supplementation significantly shortened the total parturition time and reduced the diarrhea rate in suckling piglets. On day 20 of lactation, the milk fat and protein levels increased by 9 and 4%, respectively. TB supplementation significantly improved the digestibility of dry material, gross energy, and crude fat in the sow diet, but had no significant effect on crude protein digestibility. Furthermore, TB supplementation increased the levels of IL-10, IL-6, and IgA in the blood of weaned piglets, but had no effect on maternal immunity. Analysis of the fecal microbial composition revealed that the addition of TB during late gestation and lactation increased the microbiota diversity in sows and piglets. At the phylum level, sows in the TB group had a slight increase in the relative abundance of Bacteroidota and Spirochaetota and a decrease in Firmicutes. At the order level, the relative abundance of Lactobacillales was increased in piglets and sows, and the TB group showed increased relative abundance of Enterobacterales and significantly decreased relative abundance of Oscillospirales in piglets. At family level, the relative abundance of Lactobacillaceae, Oscillospiraceae, and Christensenellaceae increased in sows, and the relative abundance of Enterobacteriaceae and Lactobacillaceae increased in piglets. At genus level, the relative abundance of Lactobacillus increased in sows and piglets, but the relative abundance of Subdoligranulum and Eubacterium_fissicatena_group decreased in piglets in the TB group.

Discussion

In conclusion, tributyrin supplementation shortened the farrowing duration and reduced the diarrhea rate of piglets by improving the inflammatory response and composition of gut microbiota in piglets and sows.

Thermal stress-related physiological, behavioral, and serum biochemical responses in indigenous pigs adapted to Eastern Himalayan region

Introduction

The current study was carried out to investigate the effect of micro-environmental variations on physiological, behavioral, and serum biochemical parameters of indigenous (Niang Megha), Hampshire, and crossbred (75% Hampshire X 25% Niang Megha).

Methods

Rectal temperature (T_R), skin surface temperature (T_SS), respiration rate (RR), and heart rate (HR) were recorded at 0,900 and 1,600 h weekly once for 2 months for each season in grower pigs of each genotype. CCTV video cameras were utilized to observe the behavioral changes. Five milliliters of blood samples was collected to estimate different biochemical parameters.

Results

Season affected (p < 0.05) all physiological parameters which generally increased during summer except T_R and RR of indigenous pig. T_R, T_SS, RR, and HR were significantly (p < 0.05) higher for Hampshire than for indigenous and crossbred in the summer season. The frequency and behavioral activities to heat loss or to conserve heat such as shivering and wallowing were lower except for physical activity that was higher at all times in indigenous pigs. Seasonal variations influenced metabolic activity and serum activity of alkaline phosphatase (ALP) and alanine transaminase (ALT), which rose in summer in all genotypes. Serum ALP and thyroxine (T₄) were significantly (p < 0.05) higher for indigenous pig in both the seasons. The insulin level was significantly (p < 0.05) higher in indigenous pigs with no significant difference between Hampshire and crossbred in summer whereas there was significant difference among the genotypes in winter. However, superoxide dismutase (SOD) showed no significant difference in the study. Indigenous pigs had the lowest serum cortisol concentrations, whereas Hampshire had the highest.

Conclusion

The current study's findings on several parameters of three different genotypes suggest that indigenous pigs in this region are more adaptable to the region's changing climatic conditions.

Factors Associated with Farrowing Duration in Hyperprolific Sows in a Free Farrowing System under Tropical Conditions

The ongoing selection for increased litter size has had significant impacts on sow husbandry practice. The present study investigated factors associated with farrowing duration and the proportion of sows that had prolonged farrowing in modern hyperprolific sows kept in a free farrowing system in a tropical environment. Farrowing data from 2493 Landrace x Yorkshire cross-bred sows in a commercial swine herd in Thailand were included in the study. The time of farrowing, parity number, litter size, and the birth status of each piglet were recorded. Farrowing duration was analysed using multiple analyses of variance. Total number of piglets born per litter (TB), parity, and time onset of farrowing were included in the statistical models. On average, TB, piglets born alive, and farrowing duration were 13.7, 12.1, and 221.0 min, respectively. Of these sows, 26.4% had TB ≥ 16 and 21.7% had a prolonged farrowing duration (≥300 min). Farrowing duration was positively correlated with TB (r = 0.141, p < 0.001), percentage of stillborn (SB) piglets per litter (r = 0.259, p < 0.001), percentage of mummified foetuses (MF) per litter (r = 0.049, p = 0.015), piglet birth weight (r = 0.068, p < 0.001), and litter birth weight (r = 0.041, p = 0.043). The proportion of SB per litter was higher and piglet birth weight lower in litters that had ≥16 TB than those with 8−12 TB (p < 0.05). The farrowing duration of sows with parity numbers 5−7 (247.7 ± 5.1 min) and 8−10 (237.1 ± 5.1 min) was longer than that of sows with parity numbers 1 (188.3 ± 5.2 min) and 2−4 (214.3 ± 3.9 min) (p < 0.05). Sows that had started farrowing during working hours had longer farrowing durations (229.3 ± 3.6 min) than those that had started farrowing during non-working hours (217.6 ± 3.4 min, p = 0.017). In multiparous sows, the duration of farrowing was positively correlated with the maximum temperature (r = 0.056, p = 0.012) and the maximum temperature−humidity index (r = 0.059, p = 0.008) in the 7 days before farrowing. The present data confirm that TB, sow parity, and time of onset of farrowing are significant risk factors for a prolonged farrowing.

Defining "Normal" in Pig Parturition

Simple Summary

The dual considerations of efficient food production and good animal welfare have never been so important nor under such strong public scrutiny as they are in current times. Intensive animal production industries play an important role in feeding an ever-growing, increasingly affluent population that is hungry for animal proteins. The efforts to improve efficiency in these production systems must not come at the cost of animal welfare. One pain point in pig production is that of parturition, where factors such as litter size and sow-housing type have been shown to influence the process and outcome. However, there are still many gaps in knowledge surrounding the normal physiology and endocrinology in a farrowing and this review seeks to summarise what is known and highlight areas where further work is required.

Abstract

Animal production industries rely on efficient and successful reproductive outcomes, with pigs being no exception. The process of parturition in pigs (farrowing) can be especially prolonged, due to the large numbers of piglets being born (on average, approximately 13 piglets per litter in Australian conditions). Difficulties in farrowing (dystocia) lead to poor piglet outcomes and health problems in sows, in turn, causing economic loss for producers and welfare concerns for the animals. Despite the importance of this topic and publications in the area stretching back nearly 50 years, there is still no consensus on the prevalence of dystocia in pigs nor on how to identify a pig experiencing the condition. Understanding the process of parturition and the factors that influence its success is a crucial step towards the early identification of sows undergoing dystocia and development of best practices to assist them. This article describes the key factors that contribute to successful farrowing and identifies areas in which more research is required before the parturition process in the pig can be fully understood.

Supplementing sows with the leucine metabolite beta-hydroxy-beta-methylbutyrate and vitamin D3 improves piglet birth weights that may lead to increased weaning weights

Previous university studies demonstrated that supplementing sows with calcium beta-hydroxy-beta-methylbutyrate (CaHMB) in late gestation and/or lactation improved piglet weights through weaning. Two studies were conducted at commercial farrowing operations to test if the results would translate to commercial operations. Sows in both trials were randomized to receive either 3 g/day CaHMB plus 500 IU/day vitamin D3 (HMB/D) or a calcium carbonate containing control top-dressed to the feed from day 104 of gestation through weaning. Sows were randomly assigned to either HMB/D (n = 41 trial 1 and n = 26 trial 2) or control (n = 46 trial 1 and n = 26 trial 2). Data were analyzed using a general linear model with main effects of group, treatment, and group by treatment interaction. Treatment with HMB/D had no effect on sow weights, lactational weight loss, and stillborn or mummified piglets. In trial 1, the control group had an increased number of live born piglets, which at 24 h tended to be greater, and no difference in liveborn or 24-h piglet numbers was seen in trial 2. In trial 1, HMB/D increased piglet live birth (P &lt; 0.03) and 24-h weights (1,490 ± 30.1 vs. 1,390 ± 28.8 g in HMB/D and control piglets, respectively, P &lt; 0.02). Farm practices were to equalize piglet numbers across sows by cross-fostering. After cross-fostering, the 24-h average piglet weights were not different, and further advantages to supplementation were not observed (P = 0.21). In trial 2, birth and 24-h weights of the piglets from HMB/D-supplemented sows were increased (P &lt; 0.0001). Piglets from sows supplemented with HMB/D were 9.7% heavier at birth and 9.2% heavier at 24 h (1,549 ± 22.0 and 1,419 ± 21.2 in HMB/D and control, respectively). A difference was observed in weaning age (P &lt; 0.0001), and weaning weights were adjusted to 21-day weights (5,426 ± 103.5 and 5,205 ± 99.5 for HMB/D and control piglets, respectively, P = 0.12). Analysis by group showed that HMB/D tended to increase weaning weights in younger sows (second and third parity), 5,432 ± 150.7 and 5,074 ± 142.7 in HMB/D and control piglets, respectively (P &lt; 0.09). In conclusion, these results agree with previous university studies demonstrating that CaHMB supplementation increased early piglet weights with a tendency to improve weaning weights.

Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

The protective role of wallowing against heat stress in gestating and lactating sows housed outdoors

The objective of this study was to describe the physiological response of gestating and lactating sows to naturally-occurring environmental conditions, and to identify factors that may contribute to or prevent heat stress, while being kept outdoors in Québec, Canada during the summer. Six groups of 4 Yorkshire-Landrace sows lived in outdoor pens equipped with a wallow, shade structure, farrowing huts and access to a pasture from July to September, 2018. Between week 15 of gestation and week 3 of lactation (inclusive), we recorded the location of each sow 5 days/week during 5 daily 15-min observation periods, and additionally measured the sow's respiratory rate and mud cover at the end of each observation period. Simultaneously, we collected sow body temperature data with vaginal temperature loggers 24h/d on week 15 of gestation and week 2 of lactation, and monitored environmental conditions with temperature and humidity loggers to calculate the temperature humidity index (THI). Sows had significantly higher and more variable body temperatures during lactation compared to gestation (P≤0.0001), and when THI was analyzed as a continuous variable, it was positively associated with sow body temperature during the night in lactation. During gestation, neither respiratory rate nor body temperature were associated with high or low levels of THI (P=0.15 and 0.79, respectively) or mud cover (P=0.29 and 0.94, respectively). However, in lactation, respiratory rate was higher when, simultaneously, THI exceeded 74 and mud cover was low (P=0.006), while a THI higher than 74 and a low mud cover had independent effects on body temperature (P=0.012 and 0.004, respectively). In lactation, sows that spent an entire observation period in the farrowing hut also had a higher respiratory rate than sows that left the hut at least once (P=0.009). In summary, lactating sows were more likely to show increases in respiratory rate and body temperature in warmer conditions than gestating sows, and our findings also suggest that time in the farrowing hut may be a risk factor for heat stress. However, mud cover may limit these physiological consequences when sows have access to a wallow.

Neonatal Piglet Temperature Changes: Effect of Intraperitoneal Warm Saline Injection

Piglets are poor at thermoregulation immediately following birth and take up to 24 h to recover from their initial temperature drop. The present study aimed to determine if providing piglets with a 15 mL intraperitoneal injection of warm (45 °C) saline at birth would improve their internal temperature recovery to 24 h of age, and how the treatment interacted with birth weight (BWC = 1; ≤0.80 kg, BWC = 2; 0.81 kg to 1.10 kg, and BWC = 3; >1.10 kg), rectal temperature at 1.5 h (RC = 1; ≤32.0 °C, RC = 2; 32.10 °C to 35.0 °C, and RC = 3; ≥35.10 °C), and colostrum intake (CI = 1; <200 g and CI = 2, ≥200 g) to affect preweaning survival. Treated BWC1 piglets had improved rectal temperatures from 2 to 24 h. BWC3 piglets who consumed insufficient colostrum also had improved rectal temperature between 1 and 24 h post-birth. Colostrum intake was improved with saline injection in BWC2 piglets of RC1 and RC3 (p < 0.001) and BWC3-RC3 piglets (p < 0.001). Treated BWC1 improved survival to 20 d (p < 0.001). Irrespective of BWC, piglets from all RC had greater survival when injected with saline. The greatest difference was for piglets in RC1, likely due to all BWC1 piglets falling within this category. The results suggest that an intraperitoneal injection of warmed saline is an effective way to improve piglet temperature recovery to 24 h, colostrum intake, and survival in low-birth-weight piglets. These findings will be helpful for producers who have large numbers of low-birth-weight piglets born and are able to provide individual care.

Systematic review of animal-based indicators to measure thermal, social, and immune-related stress in pigs

The intense nature of pig production has increased the animals’ exposure to stressful conditions, which may be detrimental to their welfare and productivity. Some of the most common sources of stress in pigs are extreme thermal conditions (thermal stress), density and mixing during housing (social stress), or exposure to pathogens and other microorganisms that may challenge their immune system (immune-related stress). The stress response can be monitored based on the animals’ coping mechanisms, as a result of specific environmental, social, and health conditions. These animal-based indicators may support decision making to maintain animal welfare and productivity. The present study aimed to systematically review animal-based indicators of social, thermal, and immune-related stresses in farmed pigs, and the methods used to monitor them. Peer-reviewed scientific literature related to pig production was collected using three online search engines: ScienceDirect, Scopus, and PubMed. The manuscripts selected were grouped based on the indicators measured during the study. According to our results, body temperature measured with a rectal thermometer was the most commonly utilized method for the evaluation of thermal stress in pigs (87.62%), as described in 144 studies. Of the 197 studies that evaluated social stress, aggressive behavior was the most frequently-used indicator (81.81%). Of the 535 publications examined regarding immune-related stress, cytokine concentration in blood samples was the most widely used indicator (80.1%). Information about the methods used to measure animal-based indicators is discussed in terms of validity, reliability, and feasibility. Additionally, the introduction and wide spreading of alternative, less invasive methods with which to measure animal-based indicators, such as cortisol in saliva, skin temperature and respiratory rate via infrared thermography, and various animal welfare threats via vocalization analysis are highlighted. The information reviewed was used to discuss the feasible and most reliable methods with which to monitor the impact of relevant stressors commonly presented by intense production systems on the welfare of farmed pigs.

Dietary Supplementation of Enzymatically Treated Artemisia annua L. Improves Lactation Performance, Alleviates Inflammatory Response of Sows Reared Under Heat Stress, and Promotes Gut Development in Preweaning Offspring

Artemisia annua L., which is known for its antimalarial compound artemisinin, has commonly been used for its anti-inflammatory and antibacterial functions. Enzymatically treating Artemisia annua L. can improve its bioavailability. The purpose of this study was to investigate the effects of dietary enzymatically treated Artemisia annua L. (EA) supplementation in late gestation and lactation diets on sow performance, serum hormone, inflammatory cytokines, and immunoglobulin level of heat-stressed sows. A total of 135 multiparous sows (Large White × Landrace) on day 85 of gestation were selected and randomly distributed into 3 groups with 45 replicates per group. The control group was reared under standard conditions (temperature: 27.12 ± 0.18°C, THI (temperature-humidity index): 70.90 ± 0.80) and fed with basal diet. The heat stress (HS) and HS + EA groups were raised in heat-stressed conditions (temperature: 30.11 ± 0.16°C, THI: 72.70 ± 0.60) and fed with basal diets supplemented with 0 or 1.0 g/kg EA, respectively. This trial lasted for 50 consecutive days until day 21 of lactation. Compared with the control group, HS increased the concentrations of serum endotoxin and heat shock protein 70 (HSP-70), and inflammatory cytokines in serum, colostrum, and 14 day milk of sows. Meanwhile, the EA supplementation decreased levels of serum endotoxin, HSP-70, and inflammatory cytokines in both sows and offspring and increased serum triiodothyronine (T₃) level and average daily feed intake (ADFI) of sows. In addition, EA significantly improved average daily gain (ADG) and altered intestinal morphology with an increased villus height in the duodenum and ileum of piglets. Collectively, EA supplementation at 1.0 g/kg in late gestation and lactation diets alleviated the adverse effects of HS, which were reflected by enhancing ADFI and decreasing endotoxin as well as inflammatory cytokine levels in the serum and colostrum of heat-stressed sows, while promoting ADG and gut development of their offspring.

Effects of Phenolic Phytogenic Feed Additives on Certain Oxidative Damage Biomarkers and the Performance of Primiparous Sows Exposed to Heat Stress under Field Conditions

The aim of this study was to investigate the effects of two commercial phenolic phytogenic feed additives (PFAs) on sows under heat stress conditions of high summer temperatures for seven days before and seven days after the farrowing. The PFA-1 product was a mixture based on the plants Emblica officinalis, Foeniculum vulgare, Citrus sinensis and nut fiber, while the PFA-2 product was a mixture based on plants Andrographis paniculata, Glycyrrhizia glabra, Tinospora cordifolia and nut fiber. A total of 48 primiparous sows were divided into three groups: T1-control group: regular gestation (GF) and lactation feed (LF); T2 group: regular GF and LF supplemented with PFA-1; T3 group: regular GF and LF supplemented with PFA-2. Each sow in the T2 and T3 groups received 5 g daily of the PFA-1 and PFA-2 product, respectively, for seven days before and seven days after the farrowing. Blood samples were collected from all groups 24 h after farrowing. Thiobarbituric acid-–reactive substances (TBARS) and protein carbonyl (CARB) concentrations were determined in the sow plasma. The body condition scoring (BCS) and the backfat of sows on the farrowing and weaning days along with reproductive parameters and litter characteristics were recorded. The highest number of stillborn piglets and the largest interval from weaning to estrus were observed in the T1 group. The lowest number of alive 24 h after birth and weaning piglets and the lowest BCS and backfat at weaning were also recorded in the T1 group. TBARS and CARB concentrations were significant higher in the T1 group compared to all other groups. In conclusion, the use of phenolic PFAs seems to reduce oxidative damage caused by heat stress and ameliorate performance in primiparous sows.

Effects of Litter Size and Parity on Farrowing Duration of Landrace × Yorkshire Sows

Simple Summary

Litter size is an important economic trait in pigs. Improving the number born alive is an important breeding goal of the pig husbandry. A shorter farrowing duration is welcome for facilitating the management and sows’ health. Therefore, the aim of this study was to explore the effect of litter size and parity on farrowing duration, to determine whether a shorter length of farrowing duration could be considered as a breeding parameter in pig breeding. Our results showed the total number born had no significant relation with farrowing duration, but number of stillbirths increased with the prolongation of farrowing duration and decrease of live litter size if farrowing duration was longer than 240–300 min. Different parities sows had little difference in the same farrowing duration interval except for gilts. A shorter farrowing duration within 300 min might be considered in pig breeding without worrying about the decreasing of live litter size or the negative effect of parity.

Abstract

Litter size has increased and farrowing duration has also prolonged in recent years. The aim of this study was to analyze the effect of litter size and parity on farrowing duration (FAR) to estimate the possibility of selecting a short farrowing duration. We recorded 32,200 parturitions of 8420 Landrace × Yorkshire sows, determined farrowing duration, litter size, parity, gestation length. Results showed that total number of born (TNB) and parity obeyed a cubic (p = 0.0004, p = 0.004) relationship while number born alive (NBA) and number born dead (NBD) obeyed a linear (p = 0.0239, p = 0.0035) relationship with FAR. Gestation length obeyed a linear (p = 0.02) relationship with FAR. FAR of sows with stillbirth was longer than that of sows without stillbirth. Stillbirth rate increased rapidly from about 2% to 4%, especially when FAR was over 240 min. FAR gradually prolonged with the parities. FAR of 7th parity sows was longer than that of 1st~6th parity sows (p < 0.05), but different parity sows had little difference in the same FAR interval except for gilts. Results indicated it was possible and necessary to consider FAR into pig breeding without worrying about decreasing of live litter size or negative effect of parity if FAR was shorter than 300 min.

Effect of drying and warming piglets at birth on preweaning mortality

Piglets are susceptible to hypothermia early after birth, which is a major predisposing factor for preweaning mortality (PWM). Drying and warming piglets at birth has been shown to reduce early postnatal temperature decline. This study evaluated the effect of drying and warming piglets at birth on PWM and weaning weight (WW) under commercial conditions. A completely randomized design was used with 802 sows/litters (10,327 piglets); sows/litters were randomly allotted at start of farrowing to one of two Intervention Treatments (applied at birth): Control (no drying or warming); Drying+Warming (dried with a cellulose-based desiccant and placed in a box under a heat lamp for 30 min). Piglets were weighed at birth and weaning; PWM was recorded. Rectal temperature was measured at 0 and 30 min after birth on all piglets in a subsample of 10% of litters. The effect of farrowing pen temperature (FPT) on WW and PWM was evaluated by comparing litters born under COOL (<25°C) to those born under WARM (≥25°C) FPT. The effect of birth weight on WW and PWM was evaluated by comparing three birth weight categories (BWC; Light: <1.0 kg, Medium: 1.0 to 1.5 kg, or Heavy: >1.5 kg). PROC GLIMMIX and MIXED of SAS were used to analyze mortality and other data, respectively. Litter was the experimental unit; piglet was a subsample of litter. The model included fixed effects of Intervention Treatment, and FPT or BWC as appropriate, the interaction, and the random effects of litter. Piglet rectal temperature at 30 min after birth was greater (P ≤ 0.05) for the Drying+Warming than the Control treatment (+2.33°C). Overall, there was no effect (P > 0.05) of Intervention Treatment on PWM or WW, and there were no Intervention Treatment by BWC interactions (P > 0.05) for these measurements. There was an Intervention Treatment by FPT interaction (P ≤ 0.05) for PWM. Drying and warming piglets reduced (P ≤ 0.05) PWM under COOL (by 2.4 percentage units) but not WARM FPT. In addition, WW were lower (P ≤ 0.05) under WARM (by 0.79 kg) than COOL FPT; however, there was no interaction (P > 0.05) with Intervention Treatment. In conclusion, this study suggests that drying and warming piglets at birth increases rectal temperature and may reduce PWM under cooler conditions, which are typically experienced in temperate climates during the majority of the year.

Evaluation of sow thermal preference across three stages of reproduction

The metabolic heat production of modern pigs has increased by an average of 16%, compared with sows of 30 years ago. Therefore, it is likely that temperature recommendations require updating to meet the needs of modern pigs. The objective of this study was to evaluate whether different reproductive stages of sows altered thermal preference and if current recommendations required updating. Twenty multiparous sows (3.4 ± 1.2 parity) in different reproductive stages (nonpregnant: n = 7; mid-gestation: 58.5 ± 5.68 d, n = 6; and late-gestation: 104.7 ± 2.8 d, n = 7) were tested. Thermal preference was individually tested, and sows could freely choose a temperature, using a thermal gradient between 10.4 and 30.5 °C. Sows were given 24 h to acclimate to the thermal apparatus. Before testing began, sows were given daily feed allotment and returned to the apparatus. Video from the 24-h test period was used to record sow behavior (time spent inactive), posture (upright and sternal and lateral lying), and location using instantaneous scan samples every 15 min. Data were analyzed using PROC MIXED procedure in SAS 9.4. A cubic regression model was used to calculate the sow's most preferred temperature based on the location, or temperature, in which they spent the most time. The preference range was calculated using peak temperature preference ±SE for each sow. The reproductive stage altered where sows spent their time within the thermal gradient (P < 0.01). Late-gestation sows preferred cooler temperatures (14.0 °C) than mid-gestation (14.8 °C; P < 0.01) and nonpregnant sows (14.8 °C; P < 0.01). In summary, sow thermal preferences were within the lower half of the current recommended range (10 to 25 °C). This indicates that temperatures at the higher end of the recommended range could be uncomfortable to sows and that the thermal comfort zone of sows may be narrower than recommendations indicate.

Effects of drying and providing supplemental oxygen to piglets at birth on rectal temperature over the first 24 h after birth

Neonatal piglets can experience both a decrease in body temperature and hypoxia, increasing risks for pre-weaning mortality. This research evaluated the effects of drying and providing supplemental oxygen to newborn piglets on rectal temperature (RT) over the first 24 h after birth. The study used a CRD with three Intervention Treatments (IT; applied at birth): Control (no intervention), Drying (dried using a desiccant), Oxygen [dried using a desiccant and placed in a chamber (at 40% oxygen concentration) for 20 min]. A total of 42 litters (485 piglets) were randomly allotted to treatments at the start of farrowing. At birth, each piglet was given a numbered ear tag, weighed, and the treatment was applied; RT was measured at 0, 20, 30, 45, 60, 120, and 1440 min after birth. Blood was collected from one piglet from each birth weight quartile within each litter at 24 h after birth to measure plasma immunocrit concentration. There was no effect (P > 0.05) of IT on piglet RT at 0 or 1440 min after birth. Between 20 and 60 min after birth, piglet RT was lower (P ≤ 0.05) for the Control than the Drying treatment, with the Oxygen treatment being intermediate and different (P ≤ 0.05) from the other two IT. The effect of piglet birth weight on responses to IT were evaluated by classifying piglets into Birth Weight Categories (BWC): Light (<1.0 kg), Medium (1.0 to 1.5 kg), or Heavy (>1.5 kg). There were IT by BWC interactions (P ≤ 0.05) for piglet RT at all measurement times between 20 and 120 min after birth. Relative to the Control, the effects of the Drying and Oxygen treatments on RT were greater (P ≤ 0.05) for Light than heavier piglets. Plasma immunocrit concentrations tended (P = 0.07) to be greater for piglets on the Control treatment compared to the other two IT and were lower (P ≤ 0.05) for Light than Heavy piglets, with Medium piglets being intermediate and different (P ≤ 0.05) to the other BWC. In conclusion, drying piglets at birth reduced the extent and duration of RT decline in piglets in the early postnatal period compared to undried piglets, especially for those of low birth weight. However, the combination of drying and placing piglets in an oxygen-rich environment provided no additional benefit over drying alone.

Influence of seasonal variation on post-farrowing dysgalactia syndrome (PFDS) and serum biochemistry profiles in the periparturient sow

The objective of this study was to investigate the effect of seasonal variation on the frequency of post-farrowing dysgalactia syndrome (PFDS), sow body condition score (BCS), piglet survival, and weaning to estrus interval under intensive management systems. In addition, the effects of PFDS on litter characteristics and serum biochemistry, oxidative stress indices, thyroid, and cortisol profile were examined in order to identify potential biomarkers in the pre-farrowing stage. The study was conducted in summer and winter seasons in Nagaland, India, on 50 sows from 30 days before farrowing until weaning at 45 days. Sows were classified retrospectively into PFDS and non-PFDS. Although statistically, no significant difference was noted in the occurrence of PFDS between the seasons, the proportion of PFDS development was substantially higher in winter than summer (37.5 vs. 26.9%). In winter, the incidence of piglet stillbirth and sow weaning to estrus period was significantly higher (p < 0.05) and the mean litter size at weaning was significantly lower (p < 0.01). At weaning, the mean litter weight and average daily weight gain were decreased (p < 0.05) in both summer and winter, and the total number of piglets died in each litter was increased in sows afflicted with PFDS compared with healthy sows. A significant interaction effect of peripartum days and PFDS was observed in the changes of blood glucose, albumin (p < 0.05), and HDL-cholesterol (p = 0.07) concentration. Mean T₃ and T₄ concentration was influenced by peripartum days in both the season and a consistently lower T₃ concentration was detected in PFDS sows before farrowing. It is concluded that PFDS sows exhibited an increased incidence of stillbirth and scouring of neonatal piglets during the winter. A pronounced drop in mean circulating T₃ concentration in sows from 30 days before farrowing to 3 days after farrowing reflects endocrine-mediated metabolic dysfunction. Further research is warranted with more number of sows to identify the critical values of serum T₃ concentration in the immediate pre-farrowing period for prediction of sows developing PFDS after farrowing.

Influence of creep feeder position on the behavior and performance of preweaning piglets and sows in a hot climate environment

The use of creep feeding for preweaning piglets is important to improve the performance of the piglets. The objective of this experiment was evaluate the effect of using or altering the position of piglet's creep feeder during lactation on piglet's performance and on behavior of piglets and sows kept in a hot climate environment. Forty-five sows and their litters at 10 days of lactation were randomly distributed into three treatments: front feeder (FF) - near the side of the sow's head; back feeder (BF) - near the side of the rump of the sow; and no feeder (NF). All piglets were weighed individually to evaluate the average weight, weight gain and coefficient of variation of the weight. Behavior assessments of the piglets and sows were recorded in 3 period. At 15 and 21 d, piglets of the FF treatment were heavier (P ≤ 0.0001) than piglets of the other treatments. At 10-21d piglets of FF treatment had 76.2% less belly nosing behavior than the NF piglets (P=0.015). The treatments had no impact on behavior of the sows. The creep feeders positioned in the front of the farrowing crate increased piglet growth rate and decreased frequency of belly nosing behavior.

Effects of cooled floor pads combined with chilled drinking water on behavior and performance of lactating sows under heat stress

This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700-1900 hours) and 23.9°C (1900-0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21-22°C) and chilled drinking water (13-15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530-1730 hours) each video-recording day. Postures (lying laterally, lying ventrally, sitting, and standing) were recorded by scanning video recordings at 5-min intervals for 24 h each video-recording day, and time budget for each posture was calculated. Rectal temperature and respiration rate were measured for all sows the day before and after farrowing, and then once weekly. Sow and litter performance was recorded. Data were analyzed using the Glimmix procedure of SAS. The cooling treatment did not affect sow behavior or litter performance. Sows in the Cool room had lower rectal temperature (P = 0.03) and lower respiration rate (P < 0.001), consumed more feed (P = 0.03), tended to have reduced weight loss (P = 0.07), and backfat loss (P = 0.07) during lactation than sows in the Control room. As lactation progressed, sows increased drinking frequency (P < 0.001) and time spent lying ventrally (P < 0.0001), standing (P < 0.001), and sitting (P < 0.0001), and decreased time spent lying laterally (P < 0.0001) in both Cool and Control rooms. While cooled floor pads combined with chilled drinking water did not affect sow behavior, they did alleviate heat stress partially, as indicated by decreased rectal temperature, respiration rate, weight, and backfat loss, and increased feed intake in lactating sows.

Effect of drying and/or warming piglets at birth under warm farrowing room temperatures on piglet rectal temperature over the first 24 h after birth

Piglets experience a decline in body temperature immediately after birth, and both drying and warming piglets at birth reduce this. However, these interventions may be less effective at higher farrowing room temperatures. This study was carried out at a commercial facility to compare the effect of drying and/or warming piglets at birth on postnatal rectal temperature (RT) under relatively warm farrowing room temperatures (26.6 ± 2.09 °C). Forty-five sows/litters were used in a completely randomized design to compare three Intervention Treatments (applied at birth): Control (no treatment); Warming (piglets placed in a plastic box under a heat lamp for 30 min); and Drying+Warming (piglets dried with desiccant and warmed as above). Temperatures in the warming boxes over the study period averaged 37.7 ± 2.75 °C. At birth, piglets were weighed; RT temperature was measured at 0, 10, 20, 30, 45, 60, 120, and 1,440 min after birth. Blood samples were collected at 24 h after birth from a subsample of one piglet from each birth weight quartile within each litter to measure plasma immunocrit concentration. Data were analyzed using PROC MIXED of SAS with litter as the experimental unit, and piglet as a subsample of litter. The model for analysis of piglet rectal temperature included fixed effects of Intervention Treatment, measurement time (repeated measure), the interaction, and the random effect of sow. Compared with the Control, piglet RT were higher (P ≤ 0.05) for the Warming treatment between 10 and 60 min, and higher (P ≤ 0.05) for the Drying+Warming treatment between 10 and 120 min after birth. Rectal temperatures were higher (P ≤ 0.05) for the Drying+Warming than the Warming treatment between 20 and 120 min. Responses to drying and/or warming were greater for low-birth-weight piglets (<1.0 kg) than heavier littermates, but were generally less than observed in previous experiments with similar treatments carried out under cooler temperatures. Piglet immunocrit values were lower (P ≤ 0.05) for the Drying+Warming treatment compared to the other Intervention Treatments, which were similar (P > 0.05). Immunocrit values tended (P = 0.10) to be lower for light (<1.0 kg) compared with heavier birth weight piglets. In conclusion, drying and warming piglets at birth was more effective for reducing piglet RT decline after birth than warming alone, though the effect was less than observed in previous studies carried out under cooler farrowing room temperatures.

Analysis of Hair Cortisol as an Indicator of Chronic Stress in Pigs in Two Different Farrowing Systems

Confinement to farrowing crates is known to prevent sows from performing natural behavior, impairing animal welfare and possibly causing chronic stress. Hair cortisol analyses are increasingly used to detect chronic stress in animals. In the present study, hair samples were collected in the neck of sows kept either in farrowing crates (FC, n = 31) or in a loose-housing system (LH, n = 30) in six batches. Cortisol was extracted and analyzed using chemiluminescence immunoassay. Mean hair cortisol concentrations (HCC) did not differ significantly between the systems (LH: 1.85 ± 0.82 pg/mg, FC: 2.13 ± 1.53 pg/mg, P = 0.631). HCC was also not affected by other factors, such as sows' parity, number of piglets, skin lesion score or sow's weight loss during the farrowing period. However, highly significant differences were found in hair growth rates between different regions within the 20 × 30 cm shaving area. While the hair in both lateral parts of the shaving area grew almost identically (left: 7.48 ± 3.52 mm, right: 7.44 ± 3.24 mm, P = 1.00), the hair grew more in the area above the spine (12.27 + 3.95 mm, P < 0.001). In both systems, the mean individual lesion score of sows declined from the beginning to the end of the housing period (P < 0.001). No difference was found between FC and LH sows at any time (P > 0.05). Since neither the amount of skin lesions nor HCC differed between LH and FC sows, it may be concluded that confining sows in farrowing crates did not affect chronic stress levels. However, results may be affected by a downregulation of the hypothalamic-pituitary-adrenal axis during long-term stress, resulting in lower cortisol levels over time. HCC in sows may also be influenced by a dominant stressor, such as farrowing or the presence of suckling piglets. Thus, for a comparison of different farrowing systems regarding chronic stress, the use of hair cortisol measurement seems to be limited. The present results revealed that differences in hair growth rate within the same body region exist. This important finding should be considered when collecting hair samples in pigs, since hair cortisol concentrations may vary depending on hair growth and length.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

The performance of piglets in nurseries may vary depending on body weight, age at weaning, management, and pathogenic load in the pig facilities. The early events in a pig's life are very important and may have long lasting consequences, since growth lag involves a significant cost to the system due to reduced market weights and increased barn occupancy. The present review evidences that there are several strategies that can be used to improve the performance and welfare of pigs at weaning. A complex set of early management and dietary strategies have been explored in sows and suckling piglets for achieving optimum and efficient growth of piglets after weaning. The management strategies studied to improve development and animal welfare include: (1) improving sow housing during gestation, (2) reducing pain during farrowing, (3) facilitating an early and sufficient colostrum intake, (4) promoting an early social interaction between litters, and (5) providing complementary feed during lactation. Dietary strategies for sows and suckling piglets aim to: (1) enhance fetal growth (arginine, folate, betaine, vitamin B12, carnitine, chromium, and zinc), (2) increase colostrum and milk production (DL-methionine, DL-2-hydroxy-4-methylthiobutanoic acid, arginine, L-carnitine, tryptophan, valine, vitamin E, and phytogenic actives), (3) modulate sows' oxidative and inflammation status (polyunsaturated fatty acids, vitamin E, selenium, phytogenic actives, and spray dried plasma), (4) allow early microbial colonization (probiotics), or (5) supply conditionally essential nutrients (nucleotides, glutamate, glutamine, threonine, and tryptophan).

Information Technologies for Welfare Monitoring in Pigs and Their Relation to Welfare Quality®

The assessment of animal welfare on-farm is important to ensure that current welfare standards are followed. The current manual assessment proposed by Welfare Quality® (WQ), although being an essential tool, is only a point-estimate in time, is very time consuming to perform, only evaluates a subset of the animals, and is performed by the subjective human. Automation of the assessment through information technologies (ITs) could provide a continuous objective assessment in real-time on all animals. The aim of the current systematic review was to identify ITs developed for welfare monitoring within the pig production chain, evaluate the ITs developmental stage and evaluate how these ITs can be related to the WQ assessment protocol. The systematic literature search identified 101 publications investigating the development of ITs for welfare monitoring within the pig production chain. The systematic literature analysis revealed that the research field is still young with 97% being published within the last 20 years, and still growing with 63% being published between 2016 and mid-2020. In addition, most focus is still on the development of ITs (sensors) for the extraction and analysis of variables related to pig welfare; this being the first step in the development of a precision livestock farming system for welfare monitoring. The majority of the studies have used sensor technologies detached from the animals such as cameras and microphones, and most investigated animal biomarkers over environmental biomarkers with a clear focus on behavioural biomarkers over physiological biomarkers. ITs intended for many different welfare issues have been studied, although a high number of publications did not specify a welfare issue and instead studied a general biomarker such as activity, feeding behaviour and drinking behaviour. The ‘good feeding’ principle of the WQ assessment protocol was the best represented with ITs for real-time on-farm welfare assessment, while for the other principles only few of the included WQ measures are so far covered. No ITs have yet been developed for the ‘Comfort around resting’ and the ‘Good human-animal relationship’ criteria. Thus, the potential to develop ITs for welfare assessment within the pig production is high and much work is still needed to end up with a remote solution for welfare assessment on-farm and in real-time.

Sows' responses to increased heat load - A review

There is a comprehensive body of literature on how increased air temperature affects the physiology, production and behaviour of sows, while very few studies consider the thermal effects of air humidity and air velocity. This review summarises studies that have investigated effects of air temperature by reviewing published literature in which sows were exposed to at least two different levels of air temperature ranging from 15 °C to 39 °C. Increased rectal temperature was investigated in the majority of the studies (26) and on average, the rectal temperature increased by 0.099 °C per °C increased air temperature above 25 °C. The increase was smaller at lower air temperatures, and it was suggested that rectal temperature is practically unaffected by air temperatures in the range of 15 °C-21 °C. This review elucidates how air temperature also affects performance indicators such as respiration rate, vaginal temperature, skin temperature, feed intake, milk yield, body weight loss during lactation, mortality, litter daily weight gain during lactation and sow behaviour. One study reported how respiration rate, rectal temperature, vaginal temperature and skin temperature were affected by both air temperature and air humidity, and the results suggest that the relative significance of air temperature and humidity may be similar for sows and finishing pigs (e.g. an increase of 40% relative humidity at an air temperature of 30 °C has a similar effect as a 1.9 °C increase in temperature). Studies on mitigation methods against the effects of high temperature and humidity such as snout cooling, drip cooling and floor cooling were reviewed to extract knowledge related to the effects of air velocity, temperatures of surrounding surfaces and the opportunity for sows to moisten their skin.

Impact of sow parity on yield and composition of colostrum and milk in Danish Landrace × Yorkshire crossbred sows

The present study aims to characterize the colostrum, milk yield and composition and to determine whether sow parity would influence yield and composition of colostrum and milk in Danish Landrace × Yorkshire crossbred sows. The data were collected from sow parity numbers 1 (n = 27), 2-4 (n = 48) and 5-6 (n = 30) from Danish Landrace × Yorkshire crossbred sows reared in a commercial swine herd in Thailand. The piglets were weighed on day 0 (<1 h), 1 (24 h), 3, 10 and 17 after birth to determine the colostrum and milk yields of the sows using a prediction equation. Milk samples were collected manually within 1 h of the onset of parturition and on days 3, 10 and 17 after farrowing to evaluate milk composition. A general linear model procedure was used to analyze the effects of sow parity numbers on colostrum yield and composition and a general linear mixed model procedure was used to analyze the effects of sow parity numbers on yield and composition of milk. The model included the fixed effects of sow parity number and time (day after parturition). The sow parity numbers 2-4 (7.0 kg) had a higher colostrum yield than 1st parity sows (5.4 kg, P =  0.002) and parity 5-6 sows (5.9 kg, P = 0.025). No evidence of parity differences was observed on milk yield (P = 0.306). No effect of sow parity numbers on fat, protein and lactose in milk was observed. The dry matter in sow parity numbers 2-4 (19.8 g/100 g) had a tendency to be higher than sow parity number 1 (18.6 g/100 g, P =  0.107) and 5-6 (18.4 g/ 100 g, P =  0.053). In conclusion, sow parity number had an impact on colostrum yield in Danish Landrace × Yorkshire crossbred sows in a tropical climate but did not influence colostrum, milk composition and milk yield. Colostrum yield in Danish Landrace × Yorkshire crossbred sows was the highest in sow parity numbers 2-4.

DNA-type results of Landrace sows for RYR1-gene and its association with productivity

Recently the assessment of QTL genes has been a relevant focus of research. Among other genes, the RYR1 is one of the most important. Research on this gene for Landrace sows of Ukrainian selection has been insufficient. This fact confirms the need for our work. A total of 63 Landrace sows from different families were evaluated by reproductive qualities for two generations. A comprehensive assessment of the sows’ reproductive ability was performed using the SIRQS-index. Determination of polymorphism in the RYR1 gene in pigs was performed by using DNA-typing of animals. Genetic potential was calculated between two generations “mother-daughter”. By assessment of polymorphism of the RYR1 gene, it was found that 6.3% of the Landrace sows were the carriers for the mutant allele of the RYR1 gene. No animals with the RYR1nn genotype were detected. Accordingly, animals with the RYR1NN genotype accounted for 93.6%. The frequency of the N allele of the RYR1 gene was 0.97, the n frequency of the RYR1 gene allele was 0.03. Sows with RYR1NN genotype had a higher level of reproductive ability compared to the RYR1Nn genotype. RYR1NN genotype also had a higher level of genetic potential. The greatest progress was established between generations of Landrace sows which were carriers for the mutant allele. The highest values of this progress were by the NBA, the lowest – by the NW. On the contrary, there was regression between populations for part of the population (Landrace sows of Ukrainian selection of RYR1Nn genotype) by the all estimated indicators of reproductive ability. Sows that were free of the mutant allele of the RYR-1 gene had high SIRQS index. The phenotypic consolidation coefficients by the NBA were lower for sows free of the mutant allele than for its carrier. The advantage of sows free of the mutant allele of the RYR-1 gene over its carrier sows was established in almost all assessed indicators of reproductive ability. No significant differences in the level of consolidation of reproductive ability between sows with different allelic variants of the RYR-1 gene were established. The higher productive level of sows with RYR1NN genotype is reflected in the indicators of economic efficiency of production. It allows higher levels of profitability to be obtained and net profit to be increased by 1093 UAH compared to sows with RYR1Nn genotype. The further monitoring of the studied gene and the gradual elimination of carriers of the mutant allele is a promising direction in breeding work.

Effects of feeding melatonin during proestrus and early gestation to gilts and parity 1 sows to minimize effects of seasonal infertility1

This study tested whether supplemental melatonin given to mimic the extended nighttime melatonin pattern observed in the higher fertility winter season could minimize infertility during summer and fall in swine. Exogenous melatonin was fed during periods coinciding with follicle selection, corpus luteum formation, pregnancy recognition, and early embryo survival. Experiments were conducted at a commercial farm in 12 sequential replicates. In Exp. 1a, mature gilts (n = 420) that had expressed a second estrus were assigned by weight to receive once daily oral Melatonin (MEL, 3 mg) or Control (CON, placebo) at 1400 h for 3 wk starting before insemination at third estrus. In Exp. 1b, parity 1 sows (n = 470) were randomly assigned by lactation length to receive MEL or CON for 3 wk, starting 2 d before weaning. Follicles, estrus, pregnancy, and farrowing data were analyzed for the main effects of treatment, season (4-wk periods), and their interaction. Environmental measures were also analyzed for reproductive responses. In Exp. 1a, there was no effect (P > 0.10) of MEL on age at third estrus (203 d), follicle size after 7 d of treatment (5.0 mm), estrous cycle length (22.6 d), return to service (9.2%), farrowing rate (FR, 80.0%), or total born pigs (TB, 13.6). However, there was an effect of season (P = 0.03) on number of follicles and on gilts expressing estrus within 23 d of the previous estrus (P < 0.005). In Exp. 1b, there was no effect of MEL (P > 0.10) on follicle measures, wean to estrous interval, FR (84.0%), or TB (13.0). But MEL (73.5%) reduced (P = 0.03) estrous expression within 7 d of weaning compared with CON (82.0%) and season (P = 0.001) decreased FR by ~14.0% during mid summer. Also, gilts and parity 1 sows exposed to low light intensity (<45 lx) during breeding had reduced conception (-8%) and farrowing (-15%) rates, compared with higher light intensity. Similarly, high temperatures (>25 °C) during breeding also reduced gilt conception rates by 7%. Although there was clear evidence of seasonal fertility failures in gilts and sows, MEL treatment did not improve fertility in gilts and reduced estrus in parity 1 sows. It is possible that differences in lighting and thermal environments before breeding could explain the differential response to MEL in sows and gilts.

Efeito de dois sistemas de resfriamento sobre os hormônios tireoidianos e as variáveis termofisiológicas de matrizes suínas em lactação

RESUMO Avaliaram-se os efeitos do sistema de resfriamento evaporativo com pressão negativa (SRE) e aspersão de água sobre o telhado (AAT), as variáveis termofisiológicas, os hormônios tireoidianos e a relação neutrófilo:linfócito (N:L) em porcas. Utilizaram-se 61 fêmeas em lactação, que foram divididas nos dois ambientes térmicos, sendo 30 em SRE e 31 em AAT, no verão. A temperatura e a umidade do ar, a frequência respiratória (FR), as temperaturas de superfície (TS) e retal (TR), a concentração de tiroxina e de tri-iodotironina, o número de neutrófilos e linfócitos e a relação N:L foram determinados. A temperatura ambiente pela manhã foi menor em SRE que em AAT (22,1ºC vs. 23,5ºC) e pela tarde (24,8ºC vs. 28,0ºC). Em ambos os períodos, a FR, a TS e a TR foram menores em SRE (de manhã 49 resp.min-1, 31,1ºC e 38,5ºC, respectivamente, e à tarde 55 resp.min-1, 30,3ºC e 38,8ºC, respectivamente) que em AAT (de manhã 54 resp.min-1, 32,8ºC e 38,6ºC, respectivamente; e à tarde 65 resp.min-1, 31,4ºC e 39,1ºC, respectivamente). Animais sob galpão AAT apresentaram menores concentrações de T4 que animais sob SRE (37,84 vs. 42,22nmol.L-1). Em ambiente tropical, no verão, porcas lactantes de ambos os sistemas mantêm a homeotermia.

Effects of dietary Clostridium butyricum addition to sows in late gestation and lactation on reproductive performance and intestinal microbiota1

This study was conducted to investigate the effects of Clostridium butyricum addition to diets in late gestation and lactation on the reproductive performance and gut microbiota for sows. A total of 180 healthy Landrace × Yorkshire sows at 90 d of gestation were randomly assigned to one of four groups, with 45 replicates per group, receiving a basal commercial diet (Control, 0% C. butyricum) or diet added with 0.1% C. butyricum (1 × 108 CFU/kg of feed), 0.2% C. butyricum (2 × 108 CFU/kg of feed), 0.4% C. butyricum (4 × 108 CFU/kg of feed), respectively. The experiment was conducted from 90 d of gestation to weaning at 21 d of lactation. The results showed that the interval between piglet born was linearly (P < 0.05) decreased, and the duration of farrowing was significantly (quadratic, P < 0.05) shortened as C. butyricum addition increased. There was a linear (P < 0.05) increase in litter weight at weaning and litter weight gain. The concentrations of IgG and IgM in colostrum, and IgM in milk were linearly increased (P < 0.05) as C. butyricum addition. Serum MDA concentrations of sows at parturition and 14 d in lactation, and piglets at 14 and 21 d of age were linearly (P < 0.05) decreased, respectively. The serum total antioxidant capacity concentrations of sows at parturition and 14 and 21 d in lactation, and piglets at 14 and 21 d of age were linearly (P < 0.05) increased as C. butyricum addition, respectively. There was a linear decrease in the serum endotoxin concentration of sows on 21 d in lactation (P < 0.05). The serum cortisol concentrations of piglets at 14 and 21 d of age were both significantly (quadratic, P < 0.05) decreased. The 0.2% C. butyricum increased the relative abundance of Bacteroidetes (P = 0.016) at phylum level, Prevotellaceae_NK3B31_group, Prevotella_1, Prevotellaceae_UCG-003, Prevotella_9, Alloprevotella (P < 0.05) at genus level, and decreased the relative abundance of Proteobacteria, Gemmatimonadetes, Actinobacteria (P < 0.001) at phylum level, and Clostridium_sensu_stricto_1, Streptococcus, Escheruchia-Shigella, Sphingomonas, Succinivibrio (P < 0.05) at genus level and Firmicutes/Bacteroidetes ratio (P = 0.020). In conclusion, the present research indicated that dietary addition with C. butyricum could shorten the duration of farrowing and enhance the growth performance of suckling piglets. Moreover, 0.2% C. butyricum administration to sows changed the composition of intestinal microbiota, especially increased the relative abundance of Prevotella.

Effect of Floor Cooling on Behavior and Heart Rate of Late Lactation Sows Under Acute Heat Stress

Much U.S. swine production is in Köppen climate types classified as "hot-summer humid continental" and "humid subtropical." As a result, farrowing sows are often exposed to temperatures above their upper critical temperature. This heat stress (HS) can affect sow welfare and productivity and have a negative economic impact. The study objective was to evaluate the impact of a cooling pad on sows' behavioral and heart rate responses to acute HS. Treatments were randomly allotted to ten multiparous sows to receive a constant cool water flow of 0.00 (CONTROL, n = 4), 0.25 (LOW, n = 2), 0.55 (MEDIUM, n = 2), or 0.85 (HIGH, n = 2) L/min for 100 min and replicated eight times, switching treatments so that each sow was exposed to each treatment. The cooling was initiated 1 h after the room reached 35°C for 100 min. Eating, drinking and nursing behaviors, postures, and heart rate were recorded before heating (Period 1), prior to cooling (Period 2), and during cooling (Period 3). There were no differences between LOW, MEDIUM, and HIGH flow rates for any periods on all behavioral and heart rate traits, so data were pooled (COOLED). There were no differences in any of the measures during Periods 1 and 2, except for the ratio of short term to long term heart rate variability (SD1:SD2) with higher values for CONTROL than COOLED sows in Period 2. During Period 3, CONTROL sows changed postures more frequently (11.5 ±1.6 vs. 5.1 ±1.6 changes per hour), spent more time drinker-pressing/drinking (4.4 ± 0.5 vs. 1.4 ± 0.4% of time), standing (6.6 ± 1.7 vs. 3.8 ± 1.6% of time), sitting (10.0 ± 1.2 vs. 4.0 ± 1.1), less time lying (83.0 ±1.8 vs. 92.0 ±1.7% of time), especially lying laterally (62.0 ± 5.6 vs. 75.0 ± 5.3% of time), than sows in all three cooling treatments (all P < 0.001). Heart rate during Period 3 was lower for COOLED sows compared to the CONTROL sows (100.2 ± 3.4 vs. 119.0 ± 4.0 beat per min, P < 0.001). Sows response to increased thermal load can be effectively reduced using water-cooled cooling pads, thereby improving sow comfort and welfare. The beneficial effects on behavior are noticeable from the lowest flow rate.

Holistic Assessment of Rumen Microbiome Dynamics through Quantitative Metatranscriptomics Reveals Multifunctional Redundancy during Key Steps of Anaerobic Feed Degradation

Ruminant livestock is a major source of the potent greenhouse gas methane. The complex rumen microbiome, consisting of bacteria, archaea, and microbial eukaryotes, facilitates anaerobic plant biomass degradation in the cow rumen, leading to methane emissions. Using an integrated approach combining multidomain quantitative metatranscriptomics with gas and volatile fatty acid (VFA) profiling, we aimed at obtaining the most comprehensive picture of the active rumen microbiome during feed degradation to date. Bacterial, archaeal, and eukaryotic biomass, but also methane emissions and VFA concentrations, increased drastically within an hour after feed intake. mRNA profiling revealed a dynamic response of carbohydrate-active enzyme transcripts, transcripts involved in VFA production and methanogenesis. While the relative abundances of functional transcripts did not mirror observed processes, such as methane emissions, transformation to mRNA abundance per gram of rumen fluid echoed ruminant processes. The microbiome composition was highly individual, with, e.g., ciliate, Neocallimastigaceae, Prevotellaceae, Succinivibrionaceae, and Fibrobacteraceae abundances differing between cows. Microbiome individuality was accompanied by inter- and intradomain multifunctional redundancy among microbiome members during feed degradation. This likely enabled the robust performance of the anaerobic degradation process in each rumen. Neocallimastigaceae and ciliates contributed an unexpectedly large share of transcripts for cellulose- and hemicellulose-degrading enzymes, respectively. Methyl-reducing but not CO2-reducing methanogens were positively correlated with methane emissions. While Methanomassiliicoccales switched from methanol to methylamines as electron acceptors, Methanosphaera became the dominating methanol-reducing methanogen. This study for the first time linked rumen meta-omics with processes and enabled holistic insights into the contribution of all microbiome members to feed degradation. IMPORTANCE Ruminant animals, such as cows, live in a tight symbiotic association with microorganisms, allowing them to feed on otherwise indigestible plant biomass as food sources. Methane is produced as an end product of the anaerobic feed degradation in ruminants and is emitted to the atmosphere, making ruminant animals among the major anthropogenic sources of the potent greenhouse gas methane. Using newly developed quantitative metatranscriptomics for holistic microbiome analysis, we here identified bacterial, archaeal, and eukaryotic key players and the short-term dynamics of the rumen microbiome during anaerobic plant biomass degradation and subsequent methane emissions. These novel insights might pave the way for novel ecologically and economically sustainable methane mitigation strategies, much needed in times of global climate change.

Influences of climatic parameters on piglet preweaning mortality in Thailand

The objective of the present study was to determine the influences of temperature, humidity, and temperature-humidity index (THI) on piglet preweaning mortality in a conventional open-housing system commercial swine herd in Thailand. The analyzed data included 11,157 litters from 3574 Landrace × Yorkshire crossbred sows. The daily temperature, humidity, and THI data were collected from a meteorological station near the herd. The associations between temperature, humidity, and THI for periods before and after farrowings and piglet preweaning mortality were analyzed. Piglet preweaning mortality (log transformation) and the proportion of litters with piglet preweaning mortality greater than 20% were analyzed by using general linear mixed models and generalized linear mixed models (GLIMMIX), respectively. On average, the piglet preweaning mortality and the proportion of litters with piglet preweaning mortality greater than 20% were 14.5% (14.2 to 14.8% CI) and 26.4% (25.5 to 27.2% CI), respectively. Piglet preweaning mortality was positively correlated with the mean temperature (r = 0.028, P = 0.003), humidity (r = 0.038, P < 0.001), and THI (r = 0.036, P < 0.001) during 0-7 days postpartum. In primiparous sows, piglet preweaning mortality increased from 12.1 to 18.5% (+ 6.4%, P < 0.001) when the mean temperature during 0-7 days postpartum increased from < 25.0 to ≥ 29 °C. However, the influence of the temperature during 0-7 days postpartum was insignificant in multiparous sows (P = 0.569, P = 0.593, and P = 0.539 in sows parity numbers 2, 3-5, and 6-9, respectively). Likewise, piglet preweaning mortality increased from 10.7 to 16.7% (+ 6.0%, P = 0.012) when humidity during 0-7 days postpartum increased from < 60 to ≥ 80% in primiparous sows but it was insignificant in sows parity numbers 3-5 (P = 0.095) and 6-9 (P = 0.219). Moreover, the proportion of the litters with piglet preweaning mortality greater than 20% in primiparous sows increased from 18.3 to 32.4% (+ 14.1%, P = 0.017) when the THI during 0-7 days postpartum increased from < 73 to ≥ 81. In conclusion, the negative influences of temperature, humidity, and THI on piglet preweaning mortality were more evident in primiparous than multiparous sows. These findings implied that strategies to reduce temperature for postpartum sows in the open-housing system in Thailand are inadequate, and the proper management of postpartum primiparous sows should be emphasized.

Supplementation of selenium, vitamin E, chromium and betaine above recommended levels improves lactating performance of sows over summer

Heat stress (HS) exacerbates the body weight loss of lactating sows and reduces litter weight gain. Selenium (Se), vitamin E (VE), chromium (Cr) and betaine have been shown to ameliorate symptoms of HS, and yeast nucleotides and mannan oligosaccharides have been reported to improve lactational performance and immune response in pigs. Therefore, a combination of these nutrients may improve lactational performance of sows in summer. The effects of two nutritionally enhanced diets on lactational performance of sows in summer were investigated in two experiments. In experiment 1, we compared the effects of a nutritionally fortified diet (0.4 ppm Se, 95 IU/kg VE, 0.4 ppm Cr and 0.2% betaine; named as SVCB diet) with the NRC 2012 standard diet (0.15 ppm Se, 44 IU/kg VE) on lactational performance of sows in summer. Results showed that the SVCB diet reduced body weight loss (P = 0.039) and tended to reduce backfat loss (P = 0.075) of sows without affecting feed intake, while litter weight gain was not influenced. In experiment 2, we further enhanced the nutrients in the SVCB diet (0.8 ppm Se, 1% yeast nucleotides, and 0.1% mannan oligosaccharides; named as SNM diet). Results showed that the SNM diet did not improve feed intake of sows, farrowing performance, or litter weight gain compared with the SVCB diet, but increased body weight loss of the third parity sows (P = 0.037). Overall, a combined supplementation of Se, VE, Cr, and betaine above the NRC recommended levels can reduce mobilisation of body reserve of lactating sows in summer.