High-yielding Dairy Cattle Research Articles

Genomic analysis reveals population structure and selection signatures in plateau dairy cattle

BackgroundTo solve the problem of an insufficient supply of dairy products in Tibet, work has been carried out to improve native dairy cattle and introduce purebred dairy cattle from low-altitude areas. The harsh environment of the plateau not only severely limits the production performance of high-yielding dairy cattle, such as Holstein and Jersey cattle, but also challenges their survival. The population structure and plateau adaptation mechanism of plateau dairy cattle are rarely reported. In this study, key genes and pathways affecting plateau purebred and crossbred dairy cattle were explored using genetic chip information.ResultsThe results showed that the genetic diversity of the Tibet dairy cattle population was higher than that of the native cattle and plains dairy cattle. Purebred Holstein and Jersey cattle in Tibet were genetically closer to dairy cattle in the plains, and crossbred dairy cattle were admixed with more Tibet cattle and Apaijiza cattle. Based on the fixation index (FST), integrated haplotype score (iHS), and cross-population extend haplotype homozygosity (XP-EHH) approaches, 60 and 40 genes were identified in plateau Holstein and Jersey cattle, respectively. A total of 78 and 70 genes were identified in crossbred cattle compared to Holstein and Tibet cattle respectively. These genes are related to cardiac health and development, neuronal development and function, angiogenesis and hematopoietic, pigmentation, growth and development, and immune response.ConclusionsOur results provide a glimpse into diverse selection signatures in plateau dairy cattle, which can be used to enhance our understanding of the genomic basis of plateau adaptation in dairy cattle. These results support further research on breeding strategies such as marker-assisted selection and gene editing in plateau dairy cattle populations.

Outbreak of persistently infected heifer calves with bovine viral diarrhea virus subgenotypes 1b and 1d in a BVDV-vaccinated open dairy herd

Outbreak of persistently infected heifer calves with bovine viral diarrhea virus subgenotypes 1b and 1d in a BVDV-vaccinated open dairy herd

Genetic analysis of rumination time based on an analysis of 77,697 Israeli dairy cows

Reduction of methane emission may become necessary for sustainable milk production. Several studies indicate a relationship between rumination time and the level of methane emission. The objectives of the current study were to estimate environmental factors affecting daily rumination time in high yielding dairy cattle, genetic parameters for rumination time across parities, environmental and genetic correlations between rumination time and economic traits and to predict the consequence of inclusion of this trait in the Israeli breeding index. The data included more than 30 million daily records from 77,697 Israeli Holstein cows for rumination time and milk production. A lactation measure of daily rumination time per cow was computed as the mean of the residuals from a linear model analysis with rumination time as the dependent variable. The independent variables were parity and the square root, linear, quadradic and inverse of days in milk by parity. Because of the shape of the lactation curve for rumination time, separate linear model analyses were performed for records up to 40 DIM and records with >40 DIM. The phenotypic correlation between first and second parity lactations for rumination time was nearly 0.8, and close to 0.7 for milk. The heritability of lactation rumination time was close to 0.44 for parities 1-3. Heritability for milk production decreased from 0.5 in first parity to 0.3 in third parity. For both traits genetic correlations among parities were all >0.9. Thus, for routine genetic analysis of rumination time, records in the different parities can be considered the same trait. The genetic correlation between rumination time and milk on first parity was 0.25 and increased slightly with increase in parity. Genetic correlations between rumination time, based on the first 40 d in milk, were economically unfavorable with retained placenta but economically favorable with metritis, ketosis and displaced abdomen. Genetic correlations between rumination time and the 9 traits included in the Israeli breeding index; milk, fat, and protein production, SCS, female fertility, herd-life, milk production persistency, calving ease, and calf mortality; were all economically favorable, except for the correlation of 0.17 with SCS. With the current index, daily rumination time with a current mean of 536 min and standard deviation of 90 min is expected to increase by 11 min per day after 10 years of selection. Inclusion of this trait with a positive index weight equivalent to 10% of the index should increase rumination time by 19 min. All changes in expected gains due to inclusion of rumination time in the index were economically positive, except for fat and SCS. Inclusion of rumination time in the index should result in 1 kg less gain in fat, a miniscule gain of 0.03 for SCS; and gains of 1.5 kg protein, 0.3% female fertility and 5 d herd-life. Even though the case for a genetic correlation between rumination time and methane emission is still weak, inclusion of this trait in the commercial index may be justified, considering that equipment is now commercially available for routine recording at reasonable cost.

How Does the Provision of Shade during Grazing Affect Heat Stress Experienced by Dairy Cows in Sweden?

Heat stress in dairy cows can cause an increase in body temperature and respiration rate, and a decreased feed intake leading to reduced production. Dairy cows are better at handling heat when they have access to shade. Therefore, this study aimed to determine the effects of providing shade to high-yielding dairy cattle during the summer in the Swedish climate. Twenty high-yielding Swedish Red dairy cows, held on pasture, were divided into two groups, one with access to shade (S) and one without (NS). Milk production was recorded daily and shade temperature and relative humidity were recorded at 10 min intervals at pasture. A major effect of heat stress was found in cows in early lactation in the NS group. In this group, a high mean temperature two days before and a high THI two days before affected the milk production negatively (p < 0.001), which was the same for the maximum temperature and maximum THI measured on the same day (p < 0.001). Increases in the mean temperature and THI two days before also affected milk production negatively (p < 0.05) for cows in early lactation in the S group, though to a lesser extent. This study suggests that dairy cows in early lactation benefit from access to shade during summer.

Extracellular Vesicles Derived from Selenium-Deficient MAC-T Cells Aggravated Inflammation and Apoptosis by Triggering the Endoplasmic Reticulum (ER) Stress/PI3K-AKT-mTOR Pathway in Bovine Mammary Epithelial Cells.

Selenium (Se) deficiency disrupts intracellular REDOX homeostasis and severely deteriorates immune and anti-inflammatory function in high-yielding periparturient dairy cattle. To investigate the damage of extracellular vesicles derived from Se-deficient MAC-T cells (SeD-EV) on normal mammary epithelial cells, an in vitro model of Se deficiency was established. Se-deficient MAC-T cells produced many ROS, promoting apoptosis and the release of inflammatory factors. Extracellular vesicles were successfully isolated by ultrahigh-speed centrifugation and identified by transmission electron microscopy, particle size analysis, and surface markers (CD63, CD81, HSP70, and TSG101). RNA sequencing was performed on exosomal RNA. A total of 9393 lncRNAs and 63,155 mRNAs transcripts were identified in the SeC and SeD groups, respectively, of which 126 lncRNAs and 955 mRNAs were differentially expressed. Furthermore, SeD-EV promoted apoptosis of normal MAC-T cells by TUNEL analysis. SeD-EV significantly inhibited Bcl-2, while Bax and Cleaved Caspase3 were greatly increased. Antioxidant capacity (CAT, T-AOC, SOD, and GSH-Px) was inhibited in SeD-EV-treated MAC-T cells. Additionally, p-PERK, p-eIF2α, ATF4, CHOP, and XBP1 were all elevated in MAC-T cells supplemented with SeD-EV. In addition, p-PI3K, p-Akt, and p-mTOR were decreased strikingly by SeD-EV. In conclusion, SeD-EV caused oxidative stress, thus triggering apoptosis and inflammation through endoplasmic reticulum stress and the PI3K-Akt-mTOR signaling pathway, which contributed to explaining the mechanism of Se deficiency causing mastitis.

Neglected bacterial infections associated to bovine respiratory disease in lactating cows from high-yielding dairy cattle herds.

Neglected bacterial infections associated to bovine respiratory disease in lactating cows from high-yielding dairy cattle herds.

Bioactive Feed Additive for the Prevention of Clostridial Disease in High-Yielding Dairy Cattle

The purpose of this research is to develop and test a new approach to prevent clostridial disease in cattle, based on the use of a new compound biologically active feed additive (BFA). Some properties of the separate components of BFA are characterized. The research showed that a strain of the bacterium Bacillus amyloliquefaciens159 has an expressed antagonism to toxin-producing strains of C. perfringens. When using the test strains of C. perfringens from the ATCC collection (13,124 as type A, 10,543 as type C, 12,916 as type F), the anticlostridial activity of the tested strains varied, with size range of 14.0 ± 0.95–15.0 ± 1.28 mm of delayed growth zones. The bactericidal properties of lauric acid and the sorption properties of diatomaceous earth, included in BFA, were confirmed. The experiment was conducted on Holstein cows at the beginning of lactation (control, C (n = 15) vs. experimental E48 (n = 15), E80 (n = 15) and E112 (n = 15), 48, 80 and 112 g/head/day BFA, respectively. All cows were vaccinated with “Coglavax” (vaccine against bovine and sheep clostridial disease, Ceva-Phylaxia VeterinaryBiologicals, Hungary), reinjected two weeks before the experiment. At the end of the experiment (3.5 months after the vaccination and 3 months after the start of BFA feeding according to the scheme of the experiment), the immune response in the control and Group E48 to C. perfringens β-toxin remained at the initial level, while the response in Group E80 and Group E112 became higher under the influence of BFA feeding. Cows fed BFA saw a guaranteed improvement in non-specific resistance. The increase in serum lysozyme concentration in cows of Groups E was 1.01–2.91 mkg/mL vs. control (p &lt; 0.001). TP, GLB, ALB/GLB vs. Groups C and E48 (p &lt; 0.001); this stabilized and normalized while feeding Group E80 and E112 animals with BFA. They also had improved nitrogen, fat, mineral metabolism, as indicated by significant increase in ALB (p &lt; 0.05), UREA (p &lt; 0.01), CHOL (p &lt; 0.01), and CHL (p &lt; 0.01) vs. Groups C and E48. Consumption of BFA increased the amount of anti-oxidants in the blood (highest TAWSA values in Group E80 14.45 mg/g, p = 0.002). Serum TBA–AP/ CP ratio was directly related to TBA–AP (r = 0.87, p &lt; 0.001), and decreased in Group E80. The milk productivity increased under the action of BFA; the average daily milk yield of the cows from the experimental groups for the period of the experiment (d0–d98) was 1.24–1.66 kg higher than that of the control. At the same time, Group E112 cows had a significant increase in milk yield (by 5.1%, p = 0.03 vs. Control). Thus, feeding BFA to dairy cows was found to improve resistance, prevent toxicoses and increase milk production of cattle, which can serve as an additional strategy for bioprotection of cattle against infection.

Genetic Polymorphism and mRNA Expression Studies Reveal IL6R and LEPR Gene Associations with Reproductive Traits in Chinese Holsteins

Genetic selection of milk yield traits alters the energy distribution of high producing cows, resulting in gene-induced negative energy balance, and consequently, poor body condition scores and reduced reproductive performances. Here, we investigated two metabolic-syndrome pathway genes, IL6R (Interleukin 6 receptor) and LEPR (Leptin receptor), for their polymorphism effects on reproductive performance in dairy cows, by applying polymorphism association analyses in 1588 Chinese Holstein cows (at population level) and gene expression analyses in granulosa cells isolated from eight cows (at cell level). Among the six single nucleotide polymorphisms we examined (two SNPs for IL6R and four SNPs for LEPR), five were significantly associated with at least one reproductive trait, including female fertility traits covering both the ability to recycle after calving and the ability to conceive and keep pregnancy when inseminated properly, as well as calving traits. Notably, the identified variant SNP g.80143337A/C in LEPR is a missense variant. The role of IL6R and LEPR in cattle reproduction were further confirmed by observed differences in relative gene expression levels amongst granulosa cells with different developmental stages. Collectively, the functional validation of IL6R and LEPR performed in this study improved our understanding of cattle reproduction while providing important molecular markers for genetic selection of reproductive traits in high-yielding dairy cattle.

Screening the Health Status of Postpartum Anoestrus Cows of Biratnagar of Nepal

High yielding dairy cattle are often prone to postpartum anestrus that retards both production and reproductive performances. To investigate the postpartum anestrus, 21 nondescript dairy cows raised in and around Biratnagar have been included in this study. The basic information regarding the breeding history, nutritional status, milk yield, suckling and frequency of milking were obtained on request from the owners. Fecal samples were collected directly from the rectum of all cows to diagnose the parasitic infestations. Rectal palpation was performed to explore the status of the ovary and other reproductive tracts. Blood samples were collected through jugular vein puncture in vials with and without anticoagulant for hematological and serobiochemical analysis. Rectal palpation revealed inactive ovaries in most of the dairy cows. The fecal and blood samples had been forwarded to Regional Veterinary Diagnostic Laboratory, Biratnagar for further analysis. Fecal examination resulted in severe parasitic infestations in 90.47% of dairy cows. The predominantly observed parasites were Paramphistomum (38%) followed by Paramphistomum + Nematodes (19%), Nematodes (9%), Liver fluke + Nematodes (9%), Liver fluke (5%), Liver fluke + Paramphistomum (5%) and Nematodes + Moniezia expansa (5%). Among all, 47.61%, 42.85%, 28.57%, 23.80% and 4.76% of cows revealed lower values for total protein (TP), hemoglobin (Hb), calcium (Ca), packed cell volume (PCV), glucose (Glc) and inorganic phosphorus (P), respectively. However, 23.80% and 9.52% of cows showed higher values of inorganic P and Glc. It was concluded that lower values of TP, Hb, Ca, PCV, Glc and inorganic P rightly held responsible for the condition of postpartum anoestrus in cows. An improved managemental practices and nutritional status of cows is suggested for the management of postpartum anoestrus in cows.

Physiological and Pyhsical Responses of Dairy Cattle to Heat Stress

Herd management and nutrition strategies against increasing negative effects of global warming on farm animals have been the subject of significant debates in recent years. The fact that the changes in the environmental conditions are directly related to the habitats of the animals and the conditions inside the barn can affect the farm animals negatively. Although effects of heat stress differ according to species, especially high-yielding dairy cattle exposed to heat stress, respond with various interactive mechanism such as physiological, biochemical, immunological, anatomical and behavioral. Therefore, with the selection practices that have been going on for many years to improve the yield characteristics of the animals significantly increased. In this respect, the increased heat load in the body of dairy cattle due to the high productivity decreases their tolerance to environmental conditions. This situation adversely affects the productivity of cows with high breeding value. Yield losses, varying according to some factors about heat stress, can be partially explained by decreasing feed intake as a result of a series of hormonal responses affecting appetite center. However, the physiological requirements of cattle must be defined in order to develop appropriate strategies to reduce or eliminate the negative effects of heat stress. In this review, the variations in physiological, biochemical and behavioral mechanisms originating from heat stress in dairy cattle and the care, nutrition and herd management strategies that can be applied to eliminate or reduce the negative effects were discussed.

Different reticuloruminal pH metrics of high-yielding dairy cattle during the transition period in relation to metabolic health, activity, and feed intake

The measurement of pH in the reticulorumen in combination with a time-pH threshold has been widely applied in research to diagnose subacute ruminal acidosis. However, other pH metrics also have biological value. In this study, 44 animals were monitored during the transition period using reticuloruminal pH boluses. Traditional and more complex pH characteristics were calculated to characterize the reticuloruminal pH profile: time pH <6, slope of a logistic cumulative pH curve (β0), and deviations [squared error (SqEr)] from pH predictions based on a harmonic static model. In this study, we aimed to examine the associations between those pH metrics and metabolic health parameters, feed intake, and activity. Finally, to describe the reticuloruminal pH dynamically, we also constructed a dynamic linear model. The results of this model were studied in relation to feed intake. All pH parameters were mutually correlated (particularly β0 and SqEr; mean Pearson correlation of -0.52). pH patterns, rather than time pH <6, were associated with metabolic health and feed intake: high variation in daily pH (β0 parameter) was reflected in higher blood concentrations of nonesterified fatty acids. Moreover, pH deviations of the harmonic model were negatively associated with feed intake and rumination behavior. This research confirms the biological importance of pH metrics focusing on pH variation and pH deviations and provides deeper insight into its associations with metabolic health status, feed intake, and activity during early lactation.

Validation of somatic cell score-associated SNPs from Holstein cattle in Sudanese Butana and Butana\u2009\xd7\u2009Holstein crossbred cattle

The Bos indicus zebu cattle Butana is the most commonly used indigenous dairy cattle breed in Sudan. In the last years, high-yielding Holstein dairy cattle were introgressed into Butana cattle to improve their milk yield and simultaneously keep their good adaption to extreme environmental conditions. With the focus on the improvement of milk production, other problems arose such as an increased susceptibility to mastitis. Thus, genetic selection for mastitis resistance should be considered to maintain healthy and productive cows. In this study, we tested 10 single nucleotide polymorphisms (SNPs) which had been associated with somatic cell score (SCS) in Holstein cattle for association with SCS in 37 purebred Butana and 203 Butana × Holstein crossbred cattle from Sudan. Animals were genotyped by competitive allele-specific PCR assays and association analysis was performed using a linear mixed model. All 10 SNPs were segregating in the crossbred Butana × Holstein populations, but only 8 SNPs in Sudanese purebred Butana cattle. The SNP on chromosome 13 was suggestively associated with SCS in the Butana × Holstein crossbred population (rs109441194, 13:79,365,467, PBF = 0.054) and the SNP on chromosome 19 was significantly associated with SCS in both populations (rs41257403, 19:50,027,458, Butana: PBF = 0.003, Butana × Holstein: PBF = 6.2 × 10−16). The minor allele of both SNPs showed an increase in SCS. Therefore, selection against the disadvantageous minor allele could be used for genetic improvement of mastitis resistance in the studied populations. However, investigations in a bigger population and across the whole genome are needed to identify additional genomic loci.

Correlation between liver lipidosis, body condition score variation, and hepatic analytes in dairy cows.

Liver lipidosis is a metabolic disorder mostly observed in high yielding dairy cattle, especially during the transition period. The aim of this study was to determine the correlation between hepatic lipid infiltration, biochemical indicators of liver function, and body condition score (BCS) variation in dairy cows. Fifty-one multiparous Holstein cows raised in a confined system were evaluated. Liver biopsies and blood samples were collected, and BCS was measured on days 3 and 28 postpartum. Lipid infiltration was determined by histologic examination. The plasma activity of aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase and concentration of beta-hydroxybutyrate, non-esterified fatty acids, albumin, total bilirubin, and cholesterol were determined. BCS was measured using objective (camera) and subjective (visual) methods. Mild lipid infiltration was found in 3.92% of cows sampled on day 3 and 5.88% on day 28. Bilirubin was significantly higher on day 3 than on day 28 postpartum, and cholesterol was significantly higher on day 28 than on day 3 in all cows. There was no difference in biochemical analytes between cows with and without lipidosis. On day 3, mean subjective BCS was 3.10 and objective BCS was 3.16, while on day 28, these scores were 2.91 and 2.99, respectively. The calculated liver function index (LFI) was found to be a more sensitive indicator of liver function than the hepatic analytes evaluated. No correlation between BCS variation and lipid infiltration was found. Cholesterol and bilirubin levels showed the most remarkable changes during the early postpartum period. LFI is a potential indicator of postpartum liver function.

Bovine Immunology: Implications for Dairy Cattle.

The growing world population (7.8 billion) exerts an increased pressure on the cattle industry amongst others. Intensification and expansion of milk and beef production inevitably leads to increased risk of infectious disease spread and exacerbation. This indicates that improved understanding of cattle immune function is needed to provide optimal tools to combat the existing and future pathogens and improve food security. While dairy and beef cattle production is easily the world’s most important agricultural industry, there are few current comprehensive reviews of bovine immunobiology. High-yielding dairy cattle and their calves are more vulnerable to various diseases leading to shorter life expectancy and reduced environmental fitness. In this manuscript, we seek to fill this paucity of knowledge and provide an up-to-date overview of immune function in cattle emphasizing the unresolved challenges and most urgent needs in rearing dairy calves. We will also discuss how the combination of available preventative and treatment strategies and herd management practices can maintain optimal health in dairy cows during the transition (periparturient) period and in neonatal calves.

Novel mixtures of Italian ryegrass and winter cereals: influence of ensiling on nutritional composition, fermentation characteristics, microbial counts and ruminal degradability

The study was conducted with the objective of evaluating the nutrient content, fermentation characteristics, microbial counts, and ruminal degradability of two mixtures of Italian ryegrass (Lolium multiflorum Lam.) and winter cereal silages. Two mixtures (mixture A: Italian ryegrass, triticale, oats, wheat and barley; and mixture B: Italian ryegrass and oats) were wilted and ensiled in laboratory‐scale silos without additives. At the end of 90 d fermentation mixture B silage had higher (p < .05) dry matter (DM), ether extract (EE), crude fibre (CF), neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents than mixture A silage. The pH value of mixture B was higher (p < .05) than mixture A silage. Mixture A had higher lactate, acetate and ethanol contents than mixture B. However, mixture B had higher NH3-N (day 14) than mixture A silage. The mould and yeast count (Log10 CFU g−1) was higher (p < .05) for mixture A than mixture B at opening day 7. The in situ incubation revealed that potentially degradable fraction (b) of DM, CP and NDF was 39.41%, 43.59%, 80.23% (mixture A) and 39.16%, 32.39%, 94.35% (mixture B). The effective protein degradability (EPD) at 0.08 rumen outflow rates was 67.26% (mixture A) and 67.19% (mixture B). These results suggest that with the proper stage of harvesting, Italian ryegrass and winter cereal mixtures were fermented well. This kind of mixtures can be ensiled without additives in the future. The high potentially degradable NDF and effective protein degradability implies that this mixture could be included successfully in high-yielding dairy cattle diets. Highlights Italian ryegrass and winter cereal mixtures are well preserved without additives and it saves the cost of additives for dairy farmers. The ensiled mixtures have high potentially degradable NDF and effective protein degradability, which improve dry matter intake, milk production and increase the net return of farm. The mixture forage can be double-cropped with corn for silage making, which can have both environmental and economic benefits if the ensiled mixture yields are enough to cover expenses.

Mid-infrared spectroscopic analysis of raw milk to predict the blood nonesterified fatty acid concentrations in dairy cows

Mid-infrared spectroscopic analysis of raw milk to predict the blood nonesterified fatty acid concentrations in dairy cows

Diagnostic performance of ultrasonography in clinical management of dairy cattle identified with left-sided ping sounds.

Objectives:Left displaced abomasum (LDA) is a common postparturient condition of high yielding dairy cattle. The diagnosis of LDA is challenging and has historically been based on findings that are not specific to the condition. The objective of the current study was to investigate the diagnostic performance of ultrasonography (USG) in the clinical management of dairy cows identified with left-sided ping sound postpartum.Materials and methods:Cows with reduced appetite postpartum and had audible left-sided ping sounds on abdominal auscultation were eligible to be prospectively recruited onto the study. The results of clinical findings and abdominal USG were recorded along with milk β-hydroxybutyrate levels, pH levels of abomaso/rumenocentesis samples, and findings on exploratory laparotomy. The diagnostic performance of USG and other clinical investigations was assessed by calculating the test sensitivity and specificity using exploratory laparotomy as a gold standard test.Results:A definitive diagnosis of LDA was made in 23 cows, 8 cows were diagnosed with peritonitis, and 4 cows with frothy tympany. The USG findings that were consistent with LDA were present in all cattle diagnosed with LDA at exploratory laparotomy. The USG findings over the past three intercostal space characteristics of LDA, however, were also present in five cases subsequently diagnosed with peritonitis and in all cases diagnosed with frothy tympany on exploratory laparotomy. The pH of abdomaso/rumenocentesis samples yielded the highest diagnostic accuracy (97.14%) as a single test in the current study.Conclusions:USG over the left abdominal wall despite being a highly sensitive test for the diagnosis of LDA has limitations as a diagnostic tool due to suboptimal specificity.

PRODUCTIVITY OF MILKING COWS USING NEW FEEDING TECHNOLOGY

The article presents research materials to study the possibility of increasing the milk productivity of high-yielding cows through the use of new technology of their feeding - through the use of protected from cleavage in the rumen protein and starch in the feed additive TEP-mix. The scientific and economic experiment was carried out on dairy cows-analogues of the first half of lactation of the Ukrainian Black-Spotted dairy breed. During the study, the actual chemical composition of feed was determined, feeding rations and compound feed recipes were developed taking into account the content of fissile protein and milk productivity of experimental animals, the actual feed consumption by cows, milk productivity, milk quality, calculated cost-effectiveness of the studied energy supplement. The difference between the rations of the control and experimental groups was the structure and composition of the feed. In the experimental group, part of the concentrated feed was replaced by energy-protein supplement TEP-mix, with a high degree (65 %) of protection against splitting in the rumen, which increased this figure in the diet of cows in general. The use of new feeding methods increased the productivity of cows with natural milk by 2.0 kg compared to the control group, the amount of fat and protein in milk - by 0.20 % and 0.17 %, respectively. As a result, the average daily hopes for the period of the experiment in terms of basic fat in the experimental group was higher by 3.9 kg, which allowed to obtain 349.2 kg more milk per cow in 89 days. In determining the economic efficiency of the use of high-yielding cows in the feeding of additives TEP-mix allowed to obtain an additional average for the period of the experiment up to 32.59 UAH. per 1 cow per day or UAH 0.98. per 1 kg of milk. The use of feed additives with a high content of protein and starch TEP-mix will allow you to balance the feeding rations of cattle more accurately, adjust the diet of high-yielding dairy cattle in the early stages of lactation to obtain maximum productivity while maintaining health and productive longevity.

RELATIONSHIP BETWEEN BLOOD METABOLIC PROFILES AND MILK YIELD ASSOCIATED WITH PARITY AND STAGE OF LACTATION IN CROSSBRED DAIRY COWS IN BANGLADESH

Background: Cattle cross-breeding program has been launched throughout Bangladesh but this program has still focused mainly on biological rather than economic evaluation. Currently, 30000 dairy farms with mainly cross-bred cows are in operation throughout the country and this intensive dairy farming system with high milk yielding dairy cows is supposed to be associated with high incidence of sub-clinical nutritional and metabolic diseases. Objectives: The objective of this study was to detect the relationship between major blood metabolic profiles and milk yield associated with parity and stage of lactation in cross-bred dairy cows. Materials and Methods: Blood samples of 220 apparently healthy lactating cross-bred dairy cows (HF x L, n = 190; SH x L, n = 20 and JS x L, n = 10) of 10 dairy herds were collected for metabolic profile test (MPT) in Bangladesh during the period from July to November 2016. The major metabolic profiles which are associated with milk fever (calcium, phosphorus &amp; magnesium) and ketosis (glucose) were considered in this study. These biochemical parameters were estimated to detect the influence of risk factors including herds, breeds, parities and lactation age of cross-bred lactating dairy cows by using the commercial kits in spectrophotometer method. Results: The evaluation of the biochemical constituents of 220 cross-bred lactating dairy cows revealed that 30% (n = 66) had hypocalcaemia and 20.45% (n = 45) had hypoglycemia. Significantly lower levels of average calcium (7.93 ± 0.36 mg/dl; p &lt; 0.024) and glucose (43.44 ± 3.63 mg/dl; p &lt; 0.0001) values were recorded in HF x L cross-bred dairy herd of BAUDF, Mymensingh in comparison to other investigated nine dairy herds. The highest milk yield was recorded at 7th parity (16 +- 0.91 liter / day) and 1st week of lactation (17.33 +- 1.09 liter / day) were associated with low mean calcium (8.09 +- 0.85 mg / dl; 6.68 +- 0.13 mg/dl) and glucose (36.45 +- 7.67 mg/dl; 32.31 +- 3.90 mg / dl) levels in comparison to the respective values of different parity and lactation weeks. Conclusions: A relationship between blood metabolic profiles and milk yield associated with herd, breed, parity and lactation stages was recorded in lactating crossbred dairy cows. The evaluation of blood metabolites at different stages of lactation cycle especially at transition period is required to detect the nutritional and metabolic health for optimum milk production and to achieve maximum reproductive potential of high yielding dairy cattle. The readily available milk samples could be used as a biological fluid to monitor the health and nutritional status of dairy cows by using mid-infrared (MIR) spectroscopy method to prevent sub-clinical metabolic disorders. Therefore, well developed laboratories with necessary equipment, test kits and reagent should be provided to perform MPT in both the blood and milk samples for practical uses. Keywords: Compton metabolic profile test, Metabolic profile, Lactating cross-bred cows, Calcium, Phosphorus, Magnesium, Glucose, Parity, Lactation stages

202 Proteomic, metabolomic and fatty acid composition in lactating and non-lactating mares&amp;rsquo; uterine fluids

In the equine industry, horse breeders aim to produce one foal per mare per year. Thus, mares are bred while nursing. In high-yielding dairy cattle, concurrent lactation and conception may affect embryo quality, but effects on uterine fluid (UF) quality are unknown. No data are available in horses. The aim of our study was to analyse the effect of nursing on protein, metabolite and fatty acid (FA) compositions of UF at ~7.5 days post-ovulation. Anglo-Arab mares (multiparous (2.7±0.9 foals), 10.8±2.5 years old) that were either nursing (N; 105±12 days of lactation) or barren (B) were inseminated with the semen of the same stallion at induction of ovulation with human chorionic gonadotrophin. Ovulation was confirmed by ultrasound within 48h. At 7.4±0.7 days post-ovulation, UF was collected with a human tampon that was left for 10min in the uterus before embryo collection. Only mares for which no embryo was collected were selected (n=5 in both groups). Trypsin digestion followed by liquid chromatography-tandem mass spectrometry analysis was used for proteomic analysis, with subsequent characterisation with the PANTHER platform using an overrepresentation test (Fisher's exact type with false discovery rate correction) with the PANTHER pathway database. An untargeted approach based on liquid chromatography-tandem mass spectrometry was performed for metabolomics (normalisation to 50µg of protein), and data were analysed with the MS Peaks to Pathways tool of the MetaboAnalyst platform, using both the GSEA and mummichog algorithms (cut-off=0.05). Fatty acid composition (% of total FA) was analysed using gas chromatography. Differences between groups were analysed using a linear model with permutation using R software with the pgirmess package (P=0.05 for significance). Altogether, 2706 proteins with at least two peptides were identified in mares’ UF, with 164 being differentially expressed. Ubiquitin proteasome, involved in embryo-endometrium interactions, was the most enriched pathway in N mares (fold enrichment=15.12; P&amp;lt;0.0001). For metabolomics, ubiquinone biosynthesis [MetaFishNet, P=0.02; NES (Enrichment Score for the variable)/(mean of all Enrichment Score in all permutations in the dataset)=1.84] was enriched in N mares. N-Glycans, mainly guanosine diphosphate mannose (Kyoto Encyclopedia of Genes and Genomes, P=0.04; NES=−1.33) and leukotriene biosynthesis (Biocyc; P=0.006; NES=−1.31), were enriched in B mares with differentially expressed leukotrienes C4/D4. The proportion of saturated FA was higher in N vs. B mares (38.4±3.6% vs. 33.2±3.6%; P=0.03), probably due to increased palmitic (P=0.08) and stearic (P=0.08) acid proportions. In conclusion, pathways involved in uterine receptivity and inflammation seem to be enriched in B mares. Fatty acids that are readily available in the diet were more present in N mares, possibly because more elaborate FA are exported to the mammary gland for milk production. Nursing could thus modify the inflammatory response in the uterine environment at ~7.5 days post-ovulation and could affect reproductive efficiency in horses.