Serum immunoglobulin concentrations and health of dairy calves in two management systems from birth to 12 weeks of age

INVITED REVIEW: An evaluation of EFSA opinion on calf welfare from a nutritional and management perspective

In March, 2023, the European Food Safety Authority published a Scientific Opinion on Calf Welfare. This Opinion was prepared in response to a request from the European Commission to provide an independent view on the welfare of calves that reflected the most recent scientific knowledge. Data sources used to develop their recommendations included peer-reviewed studies, expert knowledge, and gray literature. The Opinion considered specific scenarios and welfare consequences of specific management practices, including feeding fiber to calves raised for white veal and amount of cow-calf contact. Their Opinion suggested that calves should be fed specific quantities of forage NDF during the rearing cycle. Regarding separation of calves, the Committee recommended that the calf should remain with the cow for a minimum of 24 h and then be housed with another calf. They further suggested that prolonged cow-calf contact should increasingly be implemented due to benefits to both cow and calf to minimize stress of separation. The objective of this review is to assess the veracity of these recommendations and the scientific data that underpins them. This review will present a literature to support the contention that, from a nutritional and management perspective, these recommendations may impair calf welfare by exposing calves to innutritious rations containing excess fiber and increasing their risk of morbidity and mortality due to poor colostrum intake and exposure to disease-causing pathogens. Alternative recommendations are made that may further the goal of calf welfare in the context of nutrition and housing.

Effects of castration and eucalyptus oil supplementation on growth performance, nutrient digestibility, and blood-immunity indicators of male Holstein calves

The purpose of this study was to investigate the effects of early castration and eucalyptus oil (EUC) supplementation on dry matter intake (DMI), growth performance, and immune response of Holstein calves. Fifty-six male Holstein calves 52 d old and with an initial body weight (BW) of 63.5 ± 5.27 kg were used. The animals were blocked by BW and randomly assigned into 1 of the 4 treatment groups in a randomized complete block design with a 2 (no castration vs. castration) × 2 (without vs. with EUC) factorial arrangement of treatments. The treatments were (1) uncastrated calves fed without EUC, (2) uncastrated calves fed 0.5 g/d EUC (EUC group), (3) castrated calves (steers) fed without EUC (castrated group), and (4) steers fed with 0.5 g/d EUC (castrated + EUC). The experiment was 8 wk long, including pre- and postweaning (weaned at 72 d). The EUC × castrated interactions were not significant for DMI, growth performance, nutrient digestibility, and immune response. Castration did not affect the DMI, final BW, average daily gain (ADG), or feed efficiency, except that the ADG was greater for bull calves than for steers at postweaning. Supplementation with EUC increased DMI pre- and postweaning and increased the ADG of weaned calves. Digestibility in the total digestive tract was not affected by castration (except for organic matter digestibility), whereas adding EUC improved the digestibility of dry matter, acid detergent fiber, and crude protein. Blood concentration of IL-6 at d 94 was decreased by feeding EUC. These results indicate that the EUC could be fed to either intact or castrated dairy calves to promote growth and health postweaning; castration before weaning may reduce ADG and cause inflammatory stress without affecting feed intake or feed efficiency.

Effects of vitamin E supplementation on serum oxidative stress biomarkers, antibody titer after live bovine respiratory syncytial virus vaccination, as well as serum and fecal immunoglobulin A in weaned Japanese Black calves

The purpose of this study was to determine the effects of vitamin E supplementation on blood oxidative stress biomarker in weaned calves. Thirty clinically healthy 12 weeks of age Japanese Black calves were randomly assigned to two groups: 15 calves received 300 IU of vitamin E daily from 12 to 18 weeks of age (VE group), and the other 15 calves did not receive the vitamin E (control group). Blood samples were taken at 12, 14, 16, 18, and 20 weeks of age. The concentration of serum reactive oxygen metabolites at 20 weeks of age were significantly lower in the VE group than those in the control group. Vitamin E supplementation to weaned calves might affect blood oxidative stress.

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted.

A Scoping Review of On-Farm Colostrum Management Practices for Optimal Transfer of Immunity in Dairy Calves

Newborn calves are agammaglobulinemic and rely for their first immune protection almost completely on the transfer of immune constituents via colostrum. Inadequate colostrum management practices such as on-farm colostrum storage practices and colostrum feeding methods could affect immune components in colostrum and subsequently immune status of the newborn calf. We conducted a scoping review to identify all literature on the interactions between several colostrum management factors and immunological colostrum quality and passive transfer of immunity. Three major stages were defined: milking methods, colostrum treatment and storage, and administration procedures. Separate CAB Abstracts searches were performed for each of the subjects of interest. The search process was completed on November 9, 2020. Colostrum should be milked as soon as possible, as IgG concentration diminishes over time, probably due to dilution. To minimize bacterial contamination, it is advised to pasteurize colostrum in small batches at maximal 60°C for 30 or 60 min. Freeze/thawing of colostrum does not or only slightly affect IgG concentrations, as long as thawing is done au bain-marie and temperature does not exceed 40°C. In on-farm situations, it is difficult to determine the volume that should be fed as the variables contributing to the absorption of IgG by the newborn calf are many and include the quality of the colostrum, the bacterial contamination, the time interval between birth and first moment of feeding and the weight of the calf. Despite all knowledge regarding optimal colostrum management strategies, it remains challenging to predict the effects of certain colostrum management choices in field conditions. Therefore, we recommend measuring the colostral quality, weighing the newborn calf, adjusting the feeding volume accordingly to ensure optimal colostrum intake for each calf.

Structural characteristics of circulating immune complexes in calves with bronchopneumonia: Impact on the quiescent leukocytes

Calf bronchopneumonia is accompanied by increased level of circulating immune complexes (CIC), and we analysed size, and protein and lipid constituents of these CIC with an attempt to elucidate the connection between the CIC structural properties and their capacity to modulate leukocyte function. CIC of heathy calves (CIC_H) and calves with naturally occurring bronchopneumonia (CIC_D) were isolated by PEG precipitation and analysed by electrophoresis and chromatography. The predominant CIC proteins were IgG, albumin, and transferrin. Affinity isolated serum and CIC IgG coprecipitated several proteins, but only 75 and 80 kDa proteins bound CIC IgG, exclusively. 60 and 65 kDa proteins co-precipitated with CIC_D IgG, unlike CIC_H IgG. In both CIC_H and CIC_D, oleic acid-containing phospholipids predominated. In CIC_D, the content of oleic and vaccenic acid was higher than in CIC_H, while myristic, palmitic, stearic, linoleic and arachidonic acid showed lower content. Dynamic light scattering displayed difference in particle size distribution between CIC_H and CIC_D; 1280 nm large particles were present only in CIC_D. The effect of CIC_H and CIC_D on mononuclear cells (MNC) and granulocytes was analysed in vitro. CIC_H and CIC_D, with slight difference in intensity, stimulate MNC apoptosis, promote cell cycle arrest of unstimulated MNC, and cell cycle progression of PHA stimulated MNC. Both CIC reduced granulocyte apoptosis after 24 h while after 48 h this effect was detected for CIC_D only. These results indicate that structural differences of CIC_H and CIC_D might interfere with the CIC functional capacity, which we consider important for evaluation of CIC immunoregulatory function.

Evaluation of different analytical methods to assess failure of passive transfer in neonatal calves

The objective of this study was to evaluate different analytical methods of assessing failure of passive transfer (FPT) in neonatal calves. We hypothesized that 3 different media (i.e., centrifuged serum, centrifuged plasma, filtered plasma) and different analytical methods [i.e., ELISA, capillary electrophoresis (CE), Brix refractometer, and handheld optical refractometer] would be highly correlated with the gold standard radial immunodiffusion (RID) and would generate comparable results. Serum and plasma blood samples were collected from Holstein Friesian calves (n = 216) aged 1 to 7 d, from 2 commercial dairy herds in northeast Germany. The RID analysis showed that 59 of 216 calves (27%) had serum IgG concentrations of <10 mg/mL and 157 calves (73%) had serum concentrations of ≥10 mg/mL. The mean IgG concentration (± standard deviation) was 17.1 ± 9.8 mg/mL, and the range was 0.8 to 47.8 mg/mL. In serum, the correlation between RID and CE was r = 0.97, and between RID and ELISA was r = 0.90; CE and ELISA were also highly correlated (r = 0.89). Both refractometry methods were highly correlated with RID using centrifuged serum, centrifuged plasma, or filtered plasma (Brix refractometer: r = 0.84, 0.80, and 0.78, respectively; handheld optical refractometer: r = 0.83, 0.81, and 0.80, respectively). We determined test characteristics (optimum thresholds, sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve) for CE, ELISA, and the handheld optical and digital refractometers using receiver operating characteristic curve analyses with RID as the reference value. Optimal thresholds for assessing FPT using plasma were higher than for serum, regardless of the method of plasma harvesting. The 4 different devices had comparable areas under the curve, irrespective of the medium used. All analytical methods can be used to assess FPT.

Transfer of passive immunity in dairy calves: the effectiveness of providing a supplementary colostrum meal in addition to nursing from the dam

Failed transfer of passive immunity (FTPI) in dairy calves - which is often due to the low amount of colostrum provided within a few hours after birth - remains a crucial issue. Enabling dairy calves to nurse colostrum from their dams could be useful in increasing intake and thus avoiding FTPI, but further potential effects on the health and welfare of both calves and dams should also be considered. In this study, 107 calf-dam pairs from two Italian dairy farms were alternately assigned to one of the following colostrum provision methods (CPMs): 'hand-fed method' (HFM) - the calf was separated from the dam immediately after birth and colostrum was provided by nipple-bottle (n = 50); 'nursing method' (NM) - the calf nursed colostrum from the dam for the first 12 h of life without farmer assistance (n = 30); and 'mixed method' (MM) - the nursing calf received a supplementary colostrum meal by nipple-bottle (n = 27). Serum of calves (1 to 5 days of age) and samples of their first colostrum meal were analysed by electrophoresis to assess immunoglobulin (Ig) concentration. Additionally, behavioural indicators of separation distress (calf and dam vocalisations; calf refusal of the first meal after separation; undesirable dam behaviour at milking) in the following 24 h were recorded as binary variables (Yes/No), and the health status of calves (disease occurrence and mortality) and dams (postpartum disorders and mastitis occurrence) were monitored for the first 3 months of life and 7 days after parturition, respectively. The lowest FTPI occurrence (calf serum Ig concentration <10.0 g/l) was found in the MM (11.1%) and the HFM (22.0%) compared with the NM (60.0%) (P<0.05), and the highest percentage of calves with optimal transfer of passive immunity (serum Ig concentration ≥16.0 g/l) was observed in the MM (55.6%). The lowest calf-dam separation distress was observed in the HFM (P<0.05). The highest calf disease occurrence was recorded in the HFM (64.0%) and the lowest in the NM (33.3%), with an intermediate value for the MM (44.4%) (P<0.05). No effect of the CPM was observed on dam health or calf mortality (P>0.05). The results of this study indicated that providing calves with a supplementary colostrum meal in addition to nursing from the dam (MM) is truly effective in maximizing passive immunity transfer. Anyway, specific strategies should be studied to minimise calf-dam separation distress.

Invited review: A systematic review of the effects of early separation on dairy cow and calf health

Concern from the public is growing regarding early cow-calf separation, yet proponents of this practice maintain that artificial rearing is critical for cow and calf health. Early separation is assumed to reduce the risk of transfer of pathogens from dam to neonatal calf, but a wide range of health benefits associated with extended cow-calf contact has also been documented. The aim of this systematic review was to report and synthesize conclusions from the literature on dairy cow and calf health in conventional rearing versus cow-calf contact systems. Peer-reviewed, published manuscripts, written in English, directly comparing dairy cow or calf health in artificial versus suckling systems, were eligible for inclusion. We conducted 7 targeted searches using Web of Science to identify key literature on important health conditions. The resulting manuscripts underwent a 4-step appraisal process, and further manuscripts were sourced from reference lists. This process resulted in a final sample of 70 articles that addressed cow and calf health. Sufficient literature was available to assess mastitis in cows, and scours, cryptosporidiosis, Johne's disease, pneumonia, immunity, and mortality in calves. The results for cryptosporidiosis, pneumonia, immunity, and mortality were mixed, with some differences between studies likely attributable to flawed comparisons between cohorts. Overall, the articles addressing calf scours and mastitis pointed to beneficial or no effects of suckling. The studies addressing Johne's disease did not find cow-calf contact to be a significant risk factor. In conclusion, the scientific peer-reviewed literature on cow and calf health provides no consistent evidence in support of early separation.

Maternal Ingestion of Ipomoea carnea: Effects on Goat-Kid Bonding and Behavior

Ipomoea carnea is a toxic plant found in Brazil and other tropical and subtropical countries and often causes poisoning of livestock. The plant contains the alkaloids swainsonine and calystegines, which inhibit key cellular enzymes and cause systematic cell death. This study evaluated the behavioral effects of prenatal ingestion of this plant on dams and their kids. Twenty-four pregnant goats were randomly allocated into four treatment groups and received the following doses (g/kg BW) of fresh I. carnea: 0 (control group), 1.0 (IC1), 3.0 (IC3), and 5.0 (IC5) from day 27 of gestation until parturition. Dam and kid bonding and behavior were evaluated by several tests, immediately after birth until six weeks of age. Dams from IC3 and IC5 groups spent less time paying attention to the newborn. There was a lack of maternal-infant bonding due to I. carnea intoxication. Kids from treated dams had difficulty in standing, suckling, and in recognizing their mother hours after birth. I. carnea can also compromise the kids’ ability to learn and to retain spatial memory. We suggest that kids from pregnant goats given I. carnea during gestation have significant behavioral alterations and developmental delays that may compromise their survival.

Stress, immunity, and the management of calves

Despite many advances in management and housing of dairy calves, 1 in 10 US dairy heifers die before weaning. A better understanding of the internal and external stimuli that contribute to the physiological and behavioral responses of calves to stressors is needed to reduce the risk of morbidity and mortality. Feeding calves their first meal is crucial, as successful passive transfer reduces the risk of mortality and morbidity. Sexually dimorphic immune and stress responses appear to be present in young cattle, but more research is needed to determine if this is caused by human bias for female calves. After that first feeding, 1 in 10 heifers and most bull calves in the United States are transported to specialized calf-raising facilities, yet information is lacking on the newborn calf stress response during transit. Whether calves are raised on site or at a calf ranch, individual housing systems are commonly used in the United States to reduce the risk of pathogen exposure and provide individual feeding and healthcare. However, health, growth, and social implications may be present for calves in alternative systems with greater space allowance than conventional systems or group housing. Disbudding and castration are typically performed at an early age for dairy calves during the pre-wean stage. These stressors often take place when the calf has decreased passive transfer of Ig and immunity is developing. Availability of pain mitigation through anesthetics and analgesics is limited, but evidence indicates that analgesics attenuate suppressed leukocyte function during these procedures. Solid-feed intake is a primary measure for determining weaning readiness, but some milk replacer formulas may influence the calf's oral behaviors before weaning; therefore, alternate weaning methods may need to coincide with alternate milk replacer formulas. The calf's behavioral and stress response at weaning may influence its immunity during the transition from individual to group housing (commingling). Alternate commingling strategies and nutritional supplements may help with this transition, but more research is needed to explore feasible alternatives. Optimizing the calf's health and well-being at these early stages may improve its long-term health and welfare.

Effect of orally administered cisapride, bethanechol, and erythromycin on the apparent efficiency of colostral IgG absorption in neonatal Holstein-Friesian calves

Objective

To evaluate the effect of orally administered cisapride, bethanechol, and erythromycin on the absorption of colostral IgG in dairy calves.

Animals

Twenty‐four healthy neonatal Holstein‐Friesian calves.

Procedures

Calves were randomly assigned to one of the following treatments: 0.9% NaCl solution (2 mL, PO; negative control); erythromycin lactobionate (20 mg/kg BW, PO; anticipated to be a positive control); cisapride (0.5 mg/kg BW, PO); bethanechol chloride (0.5 mg/kg BW, PO). Calves were fed 3 L of pooled bovine colostrum containing acetaminophen (50 mg/kg) by suckling and oroesophageal intubation 30 minutes after each treatment was administered. Jugular venous blood samples were obtained periodically after the start of feeding and plasma total IgG, protein, acetaminophen, and glucose concentrations determined. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration.

Results

Oral administration of cisapride facilitated the absorption of colostral IgG and protein. The effect of cisapride on abomasal emptying rate could not be evaluated because cisapride appeared to interfere with acetaminophen metabolism. Based on the total IgG and total protein concentration‐time relationships, the beneficial effects of cisapride appeared to occur early after oral administration and were transient.

Conclusions and Clinical Importance

Additional studies appear indicated to characterize the effect of cisapride dose on the magnitude and duration of its effect on facilitating the absorption of colostral IgG and protein. Identification of a nonantimicrobial method for increasing abomasal emptying rate, such as cisapride, will potentially provide a practical and effective method for facilitating transfer of passive immunity in colostrum‐fed dairy calves.

Effect of the mass of immunoglobulin (Ig)G intake and age at first colostrum feeding on serum IgG concentration in Holstein calves

Forty-four Holstein calves (19 male and 25 female) were used in this study of the relationships among age at first colostrum feeding, IgG intake, and apparent efficiency of IgG absorption. Time of birth was recorded for each calf and the calves were fed colostrum ad libitum after birth at either 0930 or 1630 h. Blood samples were collected immediately before and 24h after colostrum feeding. Data from calves were then categorized into 4 groups representing time from birth to colostrum feeding: A=fed within 1h (n=5); B=fed from 1 to 6h (n=10); C=fed from 6 to 12 h (n=21); and D=fed from 12 to 18 h (n=8) after birth. Average total intake of colostrum was 3.6 ± 0.1L. Over 80% of the calves consumed ≥3 L of colostrum. Apparent efficiency of IgG absorption declined remarkably 12 h after birth. Mean apparent efficiency of absorption of IgG in group D (15.8 ± 3.0%) was lower than that in groups A (30.5 ± 3.9%) and B (27.4 ± 2.8%). Serum IgG concentration in calves was positively correlated with IgG intake in all groups. The relationship between mass of IgG consumed and calf serum IgG at 24 h was different for each time of colostrum feeding, with only limited differences observed between groups A and B. We concluded that failure of transfer of passive immunity in newborn calves may be avoided if calves consume ≥3 L of colostrum with IgG concentration >40 mg/mL within 6 h after birth. These findings help define the opportunity to minimize failure of transfer of passive immunity to newborn calves under management programs similar to those used on commercial dairy farms.

Views on contentious practices in dairy farming: the case of early cow-calf separation

The public has become increasingly interested in the welfare of food animals, but the food animal industries possess few mechanisms for public engagement. Here we present results from a web-based forum designed to allow stakeholders to share views on controversial issues in dairying. In response to the question "Should dairy calves be separated from the cow within the first few hours after birth?" participants were able to indicate "yes," "no," or "neutral" and either write a reason in support of their view or select reasons provided by other participants. Four independent groups of participants were recruited (a total of 163 people); 31% said they had no involvement in the dairy industry; the remaining 69% (with some involvement in the industry) were students or teachers (33%), animal advocates (13%), producers (11%), veterinarians (9%) and other dairy industry professionals (3%). Overall, little consensus existed among participants across groups; 44% chose "yes," 48% "no," and 9% "neutral." Responses varied with demographics, with opposition to early separation higher among females, animal advocates, and those with no involvement with the dairy industry. A fifth group was recruited at a dairy industry conference (an additional 28 participants); 46% chose "yes," 32% "no," and 21% "neutral." Across all 5 groups, opponents and supporters often referenced similar issues in the reasons they provided. Opponents of early separation contended that it is emotionally stressful for the calf and cow, it compromises calf and cow health, it is unnatural, and the industry can and should accommodate cow-calf pairs. In contrast, supporters of early separation reasoned that emotional distress is minimized by separating before bonds develop, that it promotes calf and cow health, and that the industry is limited in its ability to accommodate cow-calf pairs. These results illustrate the potential of web-based forums to identify areas of agreement and conflict among stakeholders, providing a basis for the development of practices that address shared concerns.

Spatio-temporal dynamics of pneumonia in bighorn sheep

1. Bighorn sheep mortality related to pneumonia is a primary factor limiting population recovery across western North America, but management has been constrained by an incomplete understanding of the disease. We analysed patterns of pneumonia-caused mortality over 14 years in 16 interconnected bighorn sheep populations to gain insights into underlying disease processes. 2. We observed four age-structured classes of annual pneumonia mortality patterns: all-age, lamb-only, secondary all-age and adult-only. Although there was considerable variability within classes, overall they differed in persistence within and impact on populations. Years with pneumonia-induced mortality occurring simultaneously across age classes (i.e. all-age) appeared to be a consequence of pathogen invasion into a naïve population and resulted in immediate population declines. Subsequently, low recruitment due to frequent high mortality outbreaks in lambs, probably due to association with chronically infected ewes, posed a significant obstacle to population recovery. Secondary all-age events occurred in previously exposed populations when outbreaks in lambs were followed by lower rates of pneumonia-induced mortality in adults. Infrequent pneumonia events restricted to adults were usually of short duration with low mortality. 3. Acute pneumonia-induced mortality in adults was concentrated in fall and early winter around the breeding season when rams are more mobile and the sexes commingle. In contrast, mortality restricted to lambs peaked in summer when ewes and lambs were concentrated in nursery groups. 4. We detected weak synchrony in adult pneumonia between adjacent populations, but found no evidence for landscape-scale extrinsic variables as drivers of disease. 5. We demonstrate that there was a >60% probability of a disease event each year following pneumonia invasion into bighorn sheep populations. Healthy years also occurred periodically, and understanding the factors driving these apparent fade-out events may be the key to managing this disease. Our data and modelling indicate that pneumonia can have greater impacts on bighorn sheep populations than previously reported, and we present hypotheses about processes involved for testing in future investigations and management.

Quantitative evaluation of genetic and environmental parameters determining antibody response induced by vaccination against bovine respiratory syncytial virus

The parameters controlling IgG antibody responses induced by vaccination against bovine respiratory syncytial virus (BRSV) were investigated in 463 Holstein-Charolais crossbred cattle. Pre- and post-vaccination sera were tested by enzyme linked immunosorbent assays (ELISA) for BRSV-specific IgG and IgG2. Year-of-birth, age, sex and pre-existing antibody were significant sources of variation for IgG responses. Pre-vaccination, progeny with a higher proportion of Holstein genes had higher total BRSV-IgG. By Day 35 post-vaccination, heritabilities peaked at 0.26 for total BRSV-IgG and 0.36 for BRSV-IgG1. There was no evidence for interbreed differences between Holstein and Charolais calves, post-vaccination. These results suggest that calf-sire has a major heritable influence on serum IgG levels following BRSV immunisation.

Imunidade passiva, morbidade neonatal e desempenho de cabritos em diferentes manejos de colostro

Objetivando determinar o manejo de colostro que permitisse a melhor aquisição de imunidade passiva em cabritos e avaliar possíveis relações entre imunidade, morbidade e desempenho, amostras de sangue foram obtidas de 58 cabritos da raça Saanen antes e 30 horas após a primeira ingestão de colostro. Os cabritos foram distribuídos em cinco grupos experimentais. No Tratamento 1 (T1) o colostro foi ingerido ad libitum durante 24 horas. Nos demais tratamentos o colostro foi fornecido em mamadeira; os cabritos do T2 ingeriram 200mL de colostro após o parto; do T3, ingeriram 400mL de colostro sendo 200mL após o parto e 200mL após 8 horas; do T4, ingeriram também 400mL de colostro, sendo 200mL após o parto, 200mL após 14 horas; e os do T5 ingeriram 600mL de colostro, 200mL após o parto, 200mL as 12 e 200mL as 24 horas. Os valores séricos de gamaglobulinas foram avaliados por eletroforese. O ganho de peso diário foi utilizado para avaliação do desempenho no período de aleitamento. A ocorrência de doenças foi registrada do nascimento até 28 dias. A menor concentração de gamaglobulinas foi encontrada nos animais do Grupo 2 (1,65g/dL) e a maior concentração foi observada no Grupo 3 (2,60g/dL). Foi observado no Grupo 3 mais animais com diarréia, porém não foram encontradas diferenças estatísticas significativas ao nível de 5%. Os diferentes manejos de colostro não estiveram associados com o desempenho dos cabritos até o final do período neonatal.

Colostrum management in calves: effects of drenching vs. bottle feeding

The objective was to examine whether the administration of colostrum by a drencher is a safe method to achieve satisfying immunoglobulin concentrations in newborn Holstein Friesian (HF)-calves. Twenty-one calves were fed 1 h postnatum with 2 l colostrum from their dam using a nipple bottle (group I); 15 calves were drenched with 4 l colostrum from their dam 1 h postnatum (group II). Thereafter, all calves were fed milk replacer exclusively. Serum concentration of total immunoglobulin [analysed by Sandwich-enzyme-linked immunosorbent assay (ELISA)] 24 h postnatum was higher in drenched calves (25.2 g/l; 12.8/52.2; median and 10/90 percentiles) compared with bottle-fed calves (14.1 g/l; 9.2/24.7). To characterize the kinetics of immunoglobulin absorption, 17 blood samples were taken frequently within 72 h postnatum using a jugular catheter in five calves fed 2 l colostrum by nipple bottle and five calves drenched with 4 l colostrum 1 h postnatum. A slightly delayed increase of serum immunoglobulin concentration (approximately 3 h) was obvious in drenched calves compared with bottle-fed calves, but drenched calves reached significantly higher immunoglobulin concentrations compared with bottle-fed calves. It is concluded that the proper application of colostrum by a drencher is a useful method for adequate colostral supply in newborn calves. The failure of the oesophageal groove reflex in drenched calves caused no clinical consequences.

Morbidity in Swedish dairy calves from birth to 90 days of age and individual calf-level risk factors for infectious diseases

The health of 3081 heifer calves born in 122 dairy herds in the south-west of Sweden from 1 January to 31 December, 1998, was monitored from birth until 90 days of age. The calves were kept either in individual pens (n=2167), in group pens, with 3-8 calves to a pen and manual feeding of milk (n=440), in group pens with 6-30 calves per pen and an automatic milk-feeding system (n=431), or with their dams (n=43). Disease incidence was recorded by farmers and project veterinarians, who clinically examined the calves and auscultated their lungs every 2-3 months. A disease was graded as 'severe' if the general loss of condition or of appetite in the calf continued for >2 days or if the animal suffered severe weight loss due to the disease. The effects of season, breed, housing, and type of colostrum feeding, and time, place and supervision of calving on the incidences of diarrhea, severe diarrhea, respiratory disease, other infectious disease and moderately to severely increased respiratory sounds, were analyzed by logistic-regression models (with herd as a random effect). The total morbidity rate was 0.081 cases per calf-month at risk. Incidence rates of arthritis, diarrhea, omphalophlebitis, respiratory disease and ringworm were 0.002, 0.035, 0.005, 0.025 and 0.009 cases per calf-months at risk, respectively. The odds ratios for diarrhea and severe diarrhea were increased in Swedish Red and Whites (OR: 1.6, 2.3) and in calves that received colostrum from first-lactation cows (OR: 1.3-1.8), and for severe diarrhea in calves born in summer or that received colostrum through suckling (OR: 1.7, 1.8). The odds ratios for respiratory disease and increased respiratory sounds were increased in calves housed in large-group pens with an automatic milk-feeding system (OR: 2.2, 2.8). Supervision of calving was associated with a decreased odds ratio for respiratory disease (OR: 0.7) and birth in individual maternity pen or tie stalls with a decreased odds ratio for increased respiratory sounds (OR: 0.5-0.6). Cross-breeds with beef breeds were associated with increased odds ratios for increased respiratory sounds (OR: 2.1-4.3) and colostrum from second-lactation cows and birth during night for other infectious disease (OR: 1.6, 1.5).

Specific immunoglobulins in serum of newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG

The apparent efficiency of absorption and the decrease of specific colostral IgG after its passage into the blood stream were determined in newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG at 30 minutes, 12 hours and 24 hours after birth. When colostrum was given at 30 minutes after birth, a value of 16.9+/-4.0 per cent of anti-peroxidase IgG ingested appeared in lamb circulation. This percentage was reduced to 9.8+/-0.8 per cent when the feeding was done at 12 hours after birth and no specific IgG was detected in lambs fed at 24 hours after birth. The concentration of anti-peroxidase IgG in lambs' serum declined quickly within 96 hours of age to about 48 per cent of the initial value, and afterwards the level decreased slowly reaching a value of 10 per cent at 32 days of age. This behaviour probably reflects the protein distribution and use of absorbed antiperoxidase IgG.

Nutrient and immunity transfer from cow to calf pre- and postcalving

Nutritional and management strategies for dairy cattle are designed to prepare the cow for lactation and to minimize the incidence of metabolic diseases around calving. However, strategies initiated during the dry period should also consider the potential effects on the calf prior to and after calving. Fetal requirements for energy and protein are significant, particularly during the last trimester of gestation. Energy requirements increase to 1.3 to 1.5 times maintenance in late pregnancy; therefore, the formulation of rations for dry cows must contain sufficient energy to support fetal growth plus maintenance. Protein requirements during pregnancy increase, particularly during the last 2 mo. Colostrum is a source of immune components and nutrients to the neonate and contains more protein, immunoglobulins (Ig), nonprotein nitrogen, fat, ash, vitamins, and minerals than does milk. Because some vitamins do not cross the placental barrier, colostrum is the primary source of these nutrients for the calf after birth. Colostrum from cows that are not supplemented with vitamin E during the dry period may provide inadequate vitamin E to calves after birth. The Ig concentration in colostrum is not markedly affected by prepartum protein nutrition; diets containing high crude protein (CP) generally increase the nonprotein fraction of colostrum, but low CP diets do not affect the CP or Ig concentration of colostrum. However, data from beef calves suggest that absorption of IgG may be impaired when low protein diets are fed during the dry period. Diets for dry cows may be balanced to reduce the cation to anion ratio, which may reduce the incidence of parturient paresis. Recent research also suggests that these diets might increase the incidence of calves born in respiratory acidosis, which may impair the acquisition of passive immunity.