Effect of milking frequency on milk immunoglobulin concentration (IgG, IgM and IgA) and chitotriosidase activity in Majorera goats

Milk Replacer Supplementation with Docosahexaenoic Acid from Microalgae Does Not Affect Growth and Immune Status in Goat Kids

Simple Summary

The consumption of docosahexaenoic acid (DHA) has beneficial effects on human health. Meat from suckling goat kids is highly valuable, especially in Mediterranean countries. Based on this, several strategies have been implemented to increase the content of DHA in foodstuffs such as meat and meat products. Several studies have observed how feeding diverse sources of DHA can improve the fatty acid profile in goat kid meat. However, few studies have focused on the effect of using these DHA supplements on growth and the immune system development in these animals. Consequently, this study aimed to evaluate the effect of different levels of DHA supplementation on growth and the immune system development in newborn goat kids. The current study showed that the DHA supplementation did not affect either growth or the immune status of goat kids during the first 35 days of life.

Abstract

Consumption of polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA), has beneficial effects for consumers’ health. Consequently, there is an increased interest in enhancing meat fatty acid profiles (i.e., PUFA and DHA content) through diverse nutritional strategies. This study aimed to investigate the effect of supplementing a microalgae-derived product rich in DHA on growth and immune system development in newborn goat kids. In this experiment, newborn goat kids were fed milk replacer (MR) supplemented with three levels of a microalgae-derived product rich in DHA (DHA-Gold^®, Martek Biosciences, MD, USA). Groups were designed as follows: MR-NS (milk replacer without DHA-Gold^® supplementation; n = 10), MR-DHA-9 (9 g of DHA-Gold^®/L milk replacer; n = 10) and MR-DHA-18 (18 g of DHA-Gold^®/L milk replacer; n = 10). The immune status of the kids was evaluated by the plasma IgG and IgM concentrations, as well as by the complement system and chitotriosidase activities. Dietary supplementation with DHA did not affect either growth or innate and humoral immunity (p > 0.05). This study concludes that supplementation with DHA does not cause negative effects on growth and immune status in newborn goat kids.

Biomarkers of fitness and welfare in dairy cattle: healthy productivity

Milk production intensification has led to several unwanted aspects, such as sustainability issues and environmental pollution. Among these, increased milk outputs that have been achieved over the last 70 years have led to several health and pathophysiological conditions in high yielding dairy animals, including metabolic diseases that were uncommon in the past. Increased occurrence of diverse metabolic diseases in cattle and other domestic animals is a key feature of domestication that not only affects the animals' health and productivity, but also may have important and adverse health impacts on human consumers through the elevated use of drugs and antibiotics. These aspects will influence economical and ethical aspects in the near future. Therefore, finding and establishing proper biomarkers for early detection of metabolic diseases is of great interest. In the present review, recent work on the discovery of fitness, stress and welfare biomarkers in dairy cows is presented, focusing in particular on possible biomarkers of energy balance and oxidative stress in plasma and milk, and biomarkers of production-related diseases and decreased fertility.

Sheep and goats raised in mixed flocks have diverse immune status around parturition

Several physiological and metabolic changes take place in dairy ruminants around parturition (late pregnancy, parturition, and early lactation). Dairy species are genetically selected for their higher milk production compared with non-dairy species. This fact causes a constant stress that impairs the immune status of the animal, with consequences for its welfare and performance. In the present study, we assessed the immune status of high-yield dairy sheep and goats by quantifying IgG and IgM concentrations, as well as chitotriosidase (ChT) and complement system [total complement system (TC) and alternative complement pathway (AC)] activity in blood plasma around parturition. We also measured IgG and IgM concentrations and ChT activity in colostrum and milk during the first 40 d postpartum. The lowest blood IgG concentration was at parturition in both species. We detected no differences in blood IgG concentrations between species. Blood IgM concentrations were constant in both species throughout the study period. However, blood IgM concentrations were greater in sheep than in goats. Blood ChT activity was greater in goats than in sheep, and both species showed constant activity of this enzyme throughout the study period. We observed no differences in complement system (TC and AC) activity between sheep and goats. In addition, both TC and AC activity were constant in both species throughout the experiment. In general, IgG and IgM concentrations were greater in sheep colostrum than in goat colostrum, but these differences disappeared after d 4 (IgG) and d 3 (IgM) postpartum. In both species, the highest IgG and IgM concentrations were measured in colostrum, gradually decreasing during the first days postpartum. Chitotriosidase activity decreased in both species from colostrum to milk, although goats always showed greater ChT activity than sheep. Both sheep and goats seemed to be more susceptible to infectious diseases around parturition. As well, goats showed greater ChT activity in blood, colostrum, and milk than sheep. This fact may give these animals additional protection against parasite and fungal infections.

Toxoplasma gondii Antibodies in Bulk Tank Milk Samples of Caprine Dairy Herds

A major public health issue, Toxoplasma gondii infection can affect humans mainly via the consumption of animal products from certain species, including small ruminants. Therefore, a regular monitoring of the infection in ovine and caprine populations is advisable for the control of human and animal toxoplasmosis. Antibody detection in individual and bulk tank milk (BTM) may represent a valid alternative to serological analysis, in that its collection is easy and does not affect animal welfare. Many serological tools for milk analysis have already been validated for several parasites, including Apicomplexa. Thus, the aim of the present study was to obtain epidemiological data on T. gondii infection through the detection of antibodies in BTM of dairy goat herds from an important area for caprine dairy production (northern Italy). The performance of a commercial ELISA was first evaluated for analysis of caprine milk samples, using a panel of serum-milk pairs of goats naturally infected by T. gondii. The analysis of BTM confirmed the presence of anti- T. gondii antibodies in 59% of the samples. Toxoplasma gondii antibody positivity was more frequently found in goats reared on farms under extensive (64.9%) or semi-intensive systems (68.7%) in comparison with intensive farms (51.1%). Analysis of milk was a valid alternative to serological tests, being easily applied in large-scale epidemiological surveys and for continuous monitoring of T. gondii infection.

Mammary gland and milk fatty acid composition of two dairy goat breeds under feed-restriction

Goat dairy products are an important source of animal protein in the tropics. During the dry season, pasture scarcity leads animals to lose up to 40% of their body weight, a condition known as Seasonal Weight Loss (SWL) that is one of the major constraints in ruminant production. Breeds with high tolerance to SWL are relevant to understand the physiological responses to pasture scarcity so they could be used in programs for animal breeding. In the Canary Islands there are two dairy goat breeds with different levels of tolerance to SWL: the Palmera, susceptible to SWL; and the Majorera, tolerant to SWL. Fat is one of the milk components most affected by environmental and physiological conditions. This study hypothesises that feed-restriction affects Majorera and Palmera breeds differently, leading to different fatty acid profiles in the mammary gland and milk. An interaction between breed and feed-restriction was observed in the mammary gland. Feed-restriction was associated with an increase in oleic acid and a decrease in palmitic acid percentage in the Palmera breed whereas no differences were observed in the Majorera breed. Palmitic and oleic acids together constituted around 60% of the total fatty acids identified, which suggests that Palmera breed is more susceptible to SWL. In milk, feed-restriction affected both breeds similarly. Regarding the interaction of the breed with the treatment, we also observed similar responses in both breeds, but this influence affects only around 2% of the total fatty acids. In general, Majorera breed is more tolerant to feed-restriction.

NMR-metabolomics profiling of mammary gland secretory tissue and milk serum in two goat breeds with different levels of tolerance to seasonal weight loss

Goats are of special importance in the Mediterranean and tropical regions for producing a variety of dairy products. The scarcity of pastures during the dry season leads to seasonal weight loss (SWL), which affects milk production. In this work, we studied the effect of feed-restriction on two dairy goat breeds, with different tolerance levels to SWL: the Majorera breed (tolerant) and the Palmera breed (susceptible). Nuclear magnetic resonance (NMR) was used to compare the metabolome of an aqueous fraction of the mammary gland and milk serum from both breeds. Goats in mid-lactation were divided by breed, and each in two feed-regime groups: the control group and the restricted-fed group (to achieve 15-20% reduction of body weight at the end of the experiment). Milk and mammary gland samples were collected at the end of the experimental period (23rd day). (1)H NMR spectra were collected from the aqueous extract of the mammary gland biopsies and the milk serum. Profiling analysis has led to the identification of 46 metabolites in the aqueous extract of the mammary gland. Lactose, glutamate, glycine and lactate were found to be the most abundant. Analysis of milk serum allowed the identification of 50 metabolites, the most abundant being lactose, citrate and creatine. Significant differences were observed, in mammary gland biopsies and milk serum, between control and restricted-fed groups in both breeds, albeit with no differences between the breeds. Variations seem to be related to metabolism adaptation to the low-energy diet and are indicative of breed-specific microflora. Milk serum showed more metabolites varying between control and restricted groups, than the mammary gland. The Majorera breed also showed more variations than the Palmera breed in milk samples, which could be an indication of a prompt adaptation to SWL by the Majorera breed.

The mammary gland in small ruminants: major morphological and functional events underlying milk production--a review

The importance of small ruminants to the dairy industry has increased in recent years, especially in developing countries, where it has a high economic and social impact. Interestingly and despite the fact that the mammary gland is the specialised milk production organ, very few authors studied the modifications occurring in the mammary gland through the lactation period in production animals, particularly in the small ruminants, sheep (Ovis aries) and goat (Capra hircus). Nevertheless, understanding the different mammary gland patterns throughout lactation is essential to improve dairy production. In addition, associating these patterns with different milking frequencies, lactation number or different diets is also of high importance, directly affecting the dairy industry. The mammary gland is commonly composed of parenchyma and stroma, which includes the ductal system, with individual proportions of each changing during the different periods and yields in a lactation cycle. Indeed, during late gestation, as well as during early to mid-lactation, mammary gland expansion occurs, with an increase in the number of epithelial cells and lumen area, which leads to increment of the parenchyma tissue, as well as a reduction of stroma, corresponding macroscopically to the increase in mammary gland volume. Throughout late lactation, the mammary gland volume decreases owing to the regression of the secretory structure. In general, common mammary gland patterns have been shown for both goats and sheep throughout the several lactation stages, although the number of studies is limited. The main objective of this manuscript is to review the colostrogenesis and lactogenesis processes as well as to highlight the mammary gland morphological patterns underlying milk production during the lactation cycle for small ruminants, and to describe potential differences between goats and sheep, hence contributing to a better description of mammary gland development during lactation for these two poorly studied species.

Short-term effects of milking frequency on milk yield, milk composition, somatic cell count and milk protein profile in dairy goats

Goats in Canary Islands are milked once a day by tradition, but in most countries with high technology on farms, goats are milked twice a day, which is known to improve milk yield. Therefore it is important to know whether the increase of milking frequency can improve the production without impairing milk quality. The objective of this study was to investigate the short term effects of three milking frequencies on milk yield, milk composition, somatic cell count (SCC) and milk protein profile in dairy goats traditionally milked once a day. Twelve Majorera goats in early lactation (48±4 d in milk) were used. During a 5-week period, goats were milked once a day (X1) in weeks 1 and 5, twice a day (X2) in weeks 2 and 4, and three times a day (X3) in week 3. Milk recording and sampling were done on the last day of each experimental week. Milk yield increased by 26% from X1 to X2. No differences were obtained when goats were switched from X2 to X3, and from X3 to X2. The goats recovered the production level when they returned to X1. Different patterns of changes in the milk constituents due to the milking frequency effect were observed. Fat percentage increased when switched from X1 to X2, then decreased from X2 to X3, and from X3 to X2, whereas it did not show significant differences from X2 to X1. Milking frequency did not affect the protein and lactose percentages. SCC values were unaffected when goats were milked X1, X2 and X3, but then they increased slightly when milking frequency was returned to X2 and X1. Finally, quantitative analysis showed an increase in intensities of milk protein bands from X1 to X2, but the intensities of casein bands (α(S1)-CN, α(S2)-CN, β-CN, κ-CN) and major whey proteins (α-La, β-Lg) decreased from X2 to X3.

From goat colostrum to milk: physical, chemical, and immune evolution from partum to 90 days postpartum

This study focused on the study of the changes originated in the milk from partum until d 90 of lactation. Ten multiparous Majorera goats, bred carefully under animal health standards, with a litter size of 2 kids (the average in this breed is 1.83 prolificacy) and similar gestation length (149 ± 1 d) were used. Goat kids were removed from their dams to avoid interferences with the study. Compositional content (fat, protein, and lactose) were measured, as well as some other properties, including pH, density, titratable acidity, ethanol stability, rennet clotting time, and somatic cell count. Moreover, immunity molecules (IgG, IgA, and IgM concentrations and chitotriosidase activity) received great attention. Fat and protein content were higher in the first days postpartum, whereas lactose content was lower. Density, titratable acidity, rennet clotting time, and somatic cell count decreased throughout the lactation period, whereas pH and ethanol stability increased. Relative to the immunological parameters, each measured parameter obtained its maximum level at d 0, showing the first milking as the choice to provide immunity to the newborn kids. On the other hand, this study might be used to establish what the best use is: processing or kid feeding.