Dairy sheep production research at the University of Wisconsin-Madison,USA-a review

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or     

Effects of Dietary Sodium Acetate on Lactation Performance and Rumen Microbiota of Dairy Goats北大核心CSCD

This experiment was conducted to investigate the effects of dietary sodium acetate on lactation performance and rumen microbiota of dairy goats. Fifteen healthy Xinong Saanen dairy goat ewes with similar body weight of (53.54±3.07) kg, the same parity (2 parities) and in mid-lactation [(60±5) d] were randomly divided into 3 groups with 5 replicates in each group. Dairy goats in the control group were fed a basal diet, and those in the experimental groups were fed the basal diet supplemented with 30 (experimental group I) and 60 g/ (d.head) (experimental group II) sodium acetate, respectively. The pre-trial period lasted for 7 days and the experimental period lasted for 21 days. The milk yield of dairy goats was recorded during the experiment. At the end of the experiment, milk samples were collected to analyze the changes in milk composition, and rumen contents of dairy goats were collected from two groups (control group and experimental group II) with significant differences in milk fat percentage. Gas chromatography and 16S rDNA sequencing technology were used to analyze the rumen fermentation parameters and rumen microbial composition and structure of dairy goats. The results showed as follows: 1) compared with the control group, dietary sodium acetate extremely significantly increased the daily milk yield of dairy goats (P<0.01), and the daily milk yield in experimental groups I and II was increased by 0.29 and 0.22 kg, respectively (P<0.01); in experimental group II, the milk fat percentage was significantly increased by 1.30 percentage points (P<0.01), and the non-fat solid content in milk was increased by 3.10% (P>0.05). 2) Compared with the control group, the rumen butyric acid content of dairy goats in experimental group II was significantly decreased (P<0.01), and there was no significant difference in rumen pH, the other volatile fatty acid content and acetic acid to propionic acid ratio (P>0.05). 3) Compared with the control group, the Sobs index, Chao1 index and Ace index of rumen microbiota in experimental group II were significantly increased (P<0.05); the results of similarity analysis (ANOSIM) also showed that there were significant differences in the structure of rumen microbiota between the two groups (P<0.05). 16S rDNA sequencing results showed that at the phylum level, Bacteroidetes and Firmicutes were the dominant phyla in the rumen of the two groups of dairy goats; at the genus level, Prevotella_1 was the dominant genus in the rumen. Compared with the control group, the relative abundances of Ruminococcus_1, Ruminococcaceae_UCG-005, Prevotellaceae_UCG-004 and Lachnoclostridium_12 in rumen of dairy goats in experimental group II were significantly increased (P<0.05), while the relative abundances of Succiniclasticum and Methanobrevibacter in rumen was significantly decreased (P<0.05). 4) The results of correlation analysis showed that rumen microbiota was correlated with daily milk yield, milk fat percentage, milk protein percentage and non-fat solid content of dairy goats. In conclusion, dietary 60 g/ (d.head) sodium acetate can significantly increase the daily milk yield and milk fat percentage, significantly reduce rumen butyrate content, and improve the lactation performance of dairy goats by improving rumen microbial composition and structure. © 2023 Authors. All rights reserved.     

Sulforaphane prevents LPS-induced inflamm tion by regulating the Nrf2-mediated autophagy pathway in goat mammary epithelial cells and a mouse model of mastitisOA

Background Mastitis not only deteriorates the composition or quality of milk, but also damages the health and productivity of dairy goats. Sulforaphane(SFN) is a phytochemical isothiocyanate compound with various pharmacological effects such as anti-oxidant and anti-inflammatory. However, the effect of SFN on mastitis has yet to be elucidated.This study aimed to explore the anti-oxidant and anti-inflammatory effects and potential molecular mechanisms of SFN in lipopolysaccharide(LPS)-induced pri...     

A significant quantitative trait locus on chromosome Z and its impact on egg production traits in seven maternal lines of meat-type chickenOA

Background: Egg production is economically important in the meat-type chicken industry. To better understand the molecular genetic mechanism of egg production in meat-type chicken, genetic parameter estimation, genome-wide association analyses combined with meta-analyses, Bayesian analyses, and selective sweep analyses were performed to screen single nucleotide polymorphisms(SNPs) and other genetic loci that were significantly associated with egg number traits in 11,279 chickens from seven mater...     

Weighted single-step GWAS and RNA sequencing reveals key candidate genes associated with physiological indicators of heat stress in Holstein cattleOA

Background: The study of molecular processes regulating heat stress response in dairy cattle is paramount for developing mitigation strategies to improve heat tolerance and animal welfare. Therefore, we aimed to identify quantitative trait loci(QTL) regions associated with three physiological indicators of heat stress response in Holstein cattle, including rectal temperature(RT), respiration rate score(RS), and drooling score(DS). We estimated genetic parameters for all three traits. Subsequentl...     

Ruminal bacterial community is associated with the variations of total milk solid content in Holstein lactating cows

Total milk solid (TMS) content directly reflects the quality of milk. Rumen bacteria ferment dietary components, the process of which generates the precursors for the synthesis of milk solid, therefore, the variation in rumen bacterial community could be associated with milk solid in dairy cows. In this study,45 healthy mid-lactation Holstein dairy cows with the similar body weight, lactation stage, and milk yield were initially used for the selection of 10 cows with high TMS (HS) and 10 cows wi...     

The market for amino acids: understanding supply and demand of substrate for more efficient milk protein synthesis

For dairy production systems, nitrogen is an expensive nutrient and potentially harmful waste product. With three quarters of fed nitrogen ending up in the manure, significant research efforts have focused on understanding and mitigating lactating dairy cows' nitrogen losses. Recent changes proposed to the Nutrient Requirement System for Dairy Cattle in the US include variable efficiencies of absorbed essential AA for milk protein production. This first separation from a purely substrate-based system, standing on the old limiting AA theory, recognizes the ability of the cow to alter the metabolism of AA. In this review we summarize a compelling amount of evidence suggesting that AA requirements for milk protein synthesis are based on a demand-driven system. Milk protein synthesis is governed at mammary level by a set of transduction pathways, including the mechanistic target of rapamycin complex 1(mTORC1), the integrated stress response(ISR), and the unfolded protein response(UPR). In tight coordination, these pathways not only control the rate of milk protein synthesis, setting the demand for AA, but also manipulate cellular AA transport and even blood flow to the mammary glands, securing the supply of those needed nutrients. These transduction pathways, specifically mTORC1, sense specific AA, as well as other physiological signals, including insulin, the canonical indicator of energy status. Insulin plays a key role on mTORC1 signaling, controlling its activation, once AA have determined mTORC1 localization to the lysosomal membrane.Based on this molecular model, AA and insulin signals need to be tightly coordinated to maximize milk protein synthesis rate. The evidence in lactating dairy cows supports this model, in which insulin and glucogenic energy potentiate the effect of AA on milk protein synthesis. Incorporating the effect of specific signaling AA and the differential role of energy sources on utilization of absorbed AA for milk protein synthesis seems like the evident following step in nutrient requirement systems to further improve N efficiency in lactating dairy cow rations.     

Supplementation with sodium butyrate improves growth and antioxidant function in dairy calves before weaning

Background: There is increasing research interest in using short-chain fatty acids(SCFAs) including butyrate as potential alternatives to antibiotic growth promoters in animal production. This study was conducted to evaluate the effects of supplementation of sodium butyrate(SB) in liquid feeds(milk, milk replacer, and the mixture of both)on the growth performance, rumen fermentation, and serum antioxidant capacity and immunoglobins in dairy calves before weaning. Forty healthy female Holstein calves(4-day-old, 40 ± 5 kg of body weight) were housed in individual hutches and randomly allocated to 1 of 4 treatment groups(n = 10 per group) using the RAND function in Excel. The control group was fed no SB(SB0), while the other three groups were supplemented with 15(SB15),30(SB30), or 45(SB45) g/d of SB mixed into liquid feeds offered. The calves were initially fed milk only(days 2 to 20), then a mixture of milk and milk replacer(days 21 to 23), and finally milk replacer only(days 24 to 60).Results: The SB supplementation enhanced growth and improved feed conversion into body weight gain compared with the SB0 group, and the average daily gain increased quadratically with increasing SB supplementation. No significant effect on rumen pH;concentrations of NH_3-N, individual and total VFAs;or acetate:propionate(A:P) ratio was found during the whole experimental period. Serum glutathione peroxidase activity increased linearly with the increased SB supplementation, while the serum concentration of maleic dialdehyde linearly decreased. Serum concentrations of immunoglobulin A, immunoglobulin G, or immunoglobulin M were not affected by the SB supplementation during the whole experimental period.Conclusions: Under the conditions of this study, SB supplementation improved growth performance and antioxidant function in pre-weaned dairy calves. We recommended 45 g/d as the optimal level of SB supplementation mixed into liquid feeds(milk or milk replacer) to improve the growth and antioxidant function of dairy calves before weaning.     

Improving the accuracy of genomic prediction for meat quality traits using whole genome sequence data in pigsOA

Background Pork quality can directly affect customer purchase tendency and meat quality traits have become valuable in modern pork production. However, genetic improvement has been slow due to high phenotyping costs. In this study, whole genome sequence(WGS) data was used to evaluate the prediction accuracy of genomic best linear unbiased prediction(GBLUP) for meat quality in large-scale crossbred commercial pigs.Results We produced WGS data(18,695,907 SNPs and 2,106,902 INDELs exceed quality co...     

A novel candidate gene CLN8 regulates fat deposition in avianOA

Background The fat deposition has a crucial role in animal meat flavor, and fat deposition-related traits are vital for breeding in the commercial duck industry. Avian fat-related traits are typical complex phenotypes, which need a large amount of data to analyze the genetic loci.Results In this study, we performed a new phenotypic analysis of fat traits and genotyped whole-genome variations for 1,246 ducks, and combed with previous GWAS data to reach 1,880 ducks for following analysis. The carc...     

Genomic patterns of homozygosity and inbreeding depression in MurcianoGranadina goatsOA

Background: Inbreeding depression can adversely affect traits related to fitness, reproduction and productive performance. Although current research suggests that inbreeding levels are generally low in most goat breeds, the impact of inbreeding depression on phenotypes of economic interest has only been investigated in a few studies based on genealogical data.Results: We genotyped 1040 goats with the Goat SNP50 BeadChip. This information was used to estimate different molecular inbreeding coeffi...     

Effects of Artemisia annua Extracts on Ruminal Fermentation Parameters in vivo,Concentration of Conjugated Linoleic Acid in the Rumen and Milk in Dairy Goats

IntroductionIt has been well established that plant oil or fish oil could enhance cis-9 trans-11CLA content in the ruminant food products.However, it is generally accepted that adding unsaturated fatty acid to ruminant diets may exert negative effects on fiber degradation and rumen microbe populations.For this reason,there is growing interest in evaluating the potential measures of increasing cis-9 trans-11CLA content in the ruminant food products.Recently some researches showed that some plants or plant extracts could increase cis-9 trans-11CLA content in milk.The objective of this experiment was to evaluate the effects of Artemisia annua Extracts (AAE) on ruminal fermentation parameters in vivo,the proportions of cis-9 trans11CLA and trans-11 C18∶1 in the ruminal fluid and in dairy goats milk.     

Mammary stem cells： expansion and animal productivity

Identification and characterization of mammary stem cells and progenitor cells from dairy animals is important in the understanding of mammogenesis, tissue turnover, lactation persistency and regenerative therapy. It has been realized by many investigators that altered lactation, long dry periods （non-milking period between two consecutive lactation cycles）, abrupt cessation of lactation （common in water buffaloes） and disease conditions like mastitis, greatly reduce milk yield thus render huge financial losses within the dairy sector. Cellular manipulation of specialized cell types within the mammary gland, called mammary stem cells （MaSCs）/progenitor cells, might provide potential solutions to these problems and may improve milk production. In addition, MaSCs/progenitor cells could be used in regenerative therapy against tissue damage caused by mastitis. This review discusses methods of MaSC/progenitor cell manipulation and their mechanisms in bovine and caprine animals. Author believes that intervention of MaSCs/progenitor cells could lessen the huge financial losses to the dairy industry globally.     

Revolutionize livestock breeding in the future: an animal embryo-stem cell breeding system in a dish

Meat and milk production needs to increase ～ 70–80% relative to its current levels for satisfying the human needs in 2050.However,it is impossible to achieve such genetic gain by conventional animal breeding systems.Based on recent advances with regard to in vitro induction of germ cell from pluripotent stem cells,herein we propose a novel embryo-stem cell breeding system.Distinct from the conventional breeding system in farm animals that involves selecting and mating individuals,the novel breeding system completes breeding cycles from parental to offspring embryos directly by selecting and mating embryos in a dish.In comparison to the conventional dairy breeding scheme,this system can rapidly achieve 30–40 times more genetic gain by significantly shortening generation interval and enhancing selection intensity.However,several major obstacles must be overcome before we can fully use this system in livestock breeding,which include derivation and mantaince of pluripotent stem cells in domestic animals,as well as in vitro induction of primordial germ cells,and subsequent haploid gametes.Thus,we also discuss the potential efforts needed in solving the obstacles for application this novel system,and elaborate on their groundbreaking potential in livestock breeding.This novel system would provide a revolutionary animal breeding system by offering an unprecedented opportunity for meeting the fast-growing meat and milk demand of humans.     

Heat stress affects dairy cow health status through blood oxygen availability

Background Rises in global warming and extreme weather occurrence make the risk of heat stress(HS) induced by high ambient temperatures more likely in high-yielding dairy cows,resulting in low milk quality and yield.In animals,oxygen is involved in many physiological and metabolic processes,but the effects of HS on oxygen metabolism remain unclear.Thus,the current study aimed to investigate how oxygen metabolism plays a role in health status of dairy cows by measuring the milk yield,milk composi...