Milk Fat Percentage Research Articles

Infertility associated with high milk fat percentage in cows

This datasheet on infertility associated with high milk fat percentage in cows covers Identity, Hosts/Species Affected.

English

The purpose of this study was to analyze milk producing traits, correlation between milk production and parities of Chinese Jersey cattle, and to make accurate prediction. For this purpose, samples for this study were taken from a large-scale breeding farm of Chinese Jersey cattle and chemically and statistically analyzed. The results of ANOVA and LSD showed that milk yield, protein percentage, somatic cell, urea nitrogen and other lactating traits of Jersey cattle of different parities were significantly different. LSD results explored that milk fat percentage decreased gradually, as the parity increased from second to third parity, while there was no difference in milk fat percentage in third and fourth parity. Similarly, protein percentage in milk was highest in second parity and then it decreased in third parity and lowest protein percentage was observed in fourth parity. Results of coefficient of variation explored that milk yield, protein and somatic cells reached the maximum value at parity 2, and the coefficient of variation of milk fat percentage and urea nitrogen reached the maximum value at parity 4. There was a significant negative correlation between milk yield and milk fat percentage, protein percentage, somatic cell and urea nitrogen in all parities. There was a positive correlation between milk fat percentage and protein percentage, somatic cell and urea nitrogen. There was a positive correlation between the protein rate and somatic cells, which was significant only at the 1st and 4th parity. There was a significant positive correlation between urea nitrogen and somatic cells at parity 1, and a negative correlation at parity 2, 3 and 4. Results of realistic estimates of achievable prediction accuracy of lactating traits showed that the amplitude of realistic estimate of prediction of milk yield, milk fat percentage, protein percentage, somatic cell and urea nitrogen in four parities were -0.65%-23.41%, -3.23%-3.92%, -3.19%-2.94%, -44.43%-29.81% and -7.83% ~ 3.97%, respectively. Based on results it is concluded that a complex correlation between the lactating traits of Jersey cattle exist and parities can significantly affect milk yield, milk protein, somatic cells and urea nitrogen of Chinese Jersey cattle

Исследование влияния «Промевита», витаминно-минеральной добавки, на производство молока и репродуктивные показатели молочных коров

At the present time vitamin-mineral and energy cows' feed additives made from natural components gain more and more popularity. The work considers the influence of the complex feeding additive "Promevit" on the indices of raw milk quality of cows and also milk productivity and indices of reproduction of animals. At adding the feed additive to the basic diet an increase in haemoglobin level of experimental cows by 21.4%, an increase in erythrocytes by 14.5%, a moderate increase in white blood cells, a slight increase (by 5.2%) in protein content in the blood of experimental cows and an increase by 6, 6% of albumin level, relatively initial indicators, increase of urea content by 23,1% within reference values, decrease of aspartataminotransferase, as well as glutamate dehydrogenase, that shows restoration of hepatobiliary system work. The milk yield of the experimental group cows was 285 kg higher than that of the control group and the percentage of milk fat was 1.3 times higher. On average the mass fraction of fat in milk of the cows from the experimental group was 3.32%, which was 4.2% higher than in the control group. There was a 10.9% increase in the amount of milk protein in raw milk compared to the initial data. The milk fat yield increased by 19.5 kg relative to the control group as well as the protein yield increased by 13.9 kg. With the use of the dietary supplement no complicated forms of hyperkeratosis were recorded in the experimental group cows, while in the control group cows' number increased by 20.7%. The number of teats with uncomplicated forms of hyperkeratosis also increased by 20% relative to baseline data. In the experimental group cows had a reduction of udder quarters with signs of clinical mastitis, the level of latent mastitis remained practically unchanged. A positive effect of the feed additive on the course of the parturition and postpartum period in cows was also noted.

Effects of cultivation conditions on biofortification of yogurt with natural folate by Propionibacterium freudenreichii

In this study, Propionibacterium (P.) freudenreichii was used for the folate production by co-culturing with traditional yogurt starter cultures in synbiotic yogurt and then it was compared to control yogurt containing only LAB starters. First, effects of process variables, including two probiotic strains, inoculum size, inulin concentration, milk fat percentage, sunflower oil content, fermentation temperature and storage time of incubation at 4 °C on folate production by P. freudenreichii were investigated using screening method of Plackett-Burman design. Then, optimization of folate production process was carried out using three main effects of inulin concentration, fermentation temperature and storage time at 4 °C using central composite design. Analysis of variance showed that the models were highly significant (p ≤ 0.05) and folate production affected by the three factors. Optimized folate production by P. freudenreichii ssp. shermanii in yogurts was achieved after 12 d of storage at 4 °C in 2% (w/v) skim-milk inulin as prebiotic and fermentation temperature of 38.6 °C. Reconfirmation assays showed that the highest produced folate included 39.2 ± 0.7 μg 100 mL-1 in FW yogurt containing P. freudenreichii ssp. shermanii under the highlighted optimum conditions, which increased by 49% of the total folate production, compared to control yogurt, which contained only LAB starters. Furthermore, textural properties were assessed using texture analysis. Coculture of P. freudenreichii with traditional yogurt starter culture and addition of inulin to yogurt samples increased hardness, consistency and cohesiveness values in yogurt samples. Results showed that by co-culturing of P. freudenreichii ssp. shermanii in yogurt, in addition to producing a probiotic product, also increases the amount of folate production compared to control yogurt, which contained only LAB starters.

COMPARATIVE EFFICIENCYOF USING DIFFERENT EQUIPMENT FOR OBTAINING AND PRIMARY PROCESSING OF MILK

It has been established that the conditions for obtaining and primary processing of milk have a certain impact on its quality due to using more technologically advanced milking equipment, its timely maintenance, and the use of modern purification and cooling methods. The fat percentage in cows' milk was higher at MTC Zavechelie by 0.19 p.p., and protein percentage – at MTF Matyrino by 0.01 p.p. The level of somatic cells in milk produced at the MTC Zavechelye was lower by 24.0 thousand CFU/cm3 than at the MTF Matyrino, the level of bacterial contamination of milk was lower by 9.0 thousand CFU/cm3 (Р<0 .05).

Implications of negative energy balance in lactating Barki and Rahmani ewes

Context During lactation, ewes usually undergo a state of negative energy balance since the energy required for milk production and maintenance of body tissue functions exceeds energy ingested. Aims This study was performed to explore the impact of negative energy balance associated with lactation on milk yield and composition, metabolic profile and some reproductive traits in two different breeds of sheep. Methods In total, one hundred lactating Barki and Rahmani ewes (50 ewes per breed) were used for six consecutive parities to investigate the effects of breed, parity, week of lactation, and their interactions on milk yield and composition, including percentages of milk fat and milk protein, fat–protein ratio, energy-corrected milk, milk energy value, energy balance, some serum metabolites and reproductive traits. Milk and blood samples were collected weekly throughout the study. Key results Rahmani ewes had higher milk fat %, fat yield, protein %, protein yield and milk energy value, but lower fat–protein ratio than did Barki ewes. The greater value of energy balance and accumulated negative energy balance from parturition to energy balance equilibrium and fewer days from lambing to energy balance equilibrium were observed in Rahmani than in Barki ewes. Greater values of serum concentrations of total protein, albumin, cholesterol and lower values of aspartate aminotransferase and alanine aminotransferase were recorded in Rahmani than in Barki ewes. Reproductive traits, including days to the first oestrus and days to conception, recorded greater values in Barki than in Rahmani ewes. Conclusion Rahmani ewes possessed adaptive characteristics to the challenge of lactation, expressed as a lower value of fat–protein ratio, which indicated a tendency of energy balance stabilisation, than did Barki ewes. This tendency was reflected in improved reproductive traits by reducing days to first oestrus and days to conception in Rahmani compared with Barki ewes. Implications Lactation presents a critical stressful period in the dam productive life because of the high nutritional and other managerial requirements necessary for milk production. This study was conducted to assess and compare the sustainability of the two sheep breeds to the production expenditure during lactation.

Phytonutrient pellet supplementation enhanced rumen fermentation efficiency and milk production of lactating Holstein-Friesian crossbred cows.

The objective of this experiment was to investigate the effects of inclusion of dragon fruit peel pellet (DFPP) and dietary non-protein nitrogen (NPN) on nutrients digestibility, rumen fermentation efficiency, plasma antioxidant activity, microbial protein synthesis, milk yield and composition in lactating Holstein-Friesian crossbred cows. Four animals were randomly allotted to 4 dietary treatments according to a 2 × 2 factorial arrangement in 4 × 4 Latin square design. The treatments were as follows: 300 g DM of DFPP +100 g of urea (T1), 300 g DM of DFPP + 200 g of urea (T2), 400 g DM of DFPP + 100 g of urea (T3), and 400 g DM of DFPP + 200 g of urea (T4), respectively. The results showed that intake of rice straw was increased (P < 0.01) by the DFPP addition. Including DFPP and urea did not affect (P > 0.05) the NDF and ADF digestibilities, but increased the apparent digestibilities of dry matter, organic matter, and crude protein (P < 0.01). Rumen fermentation process, especially the propionate concentration, was significantly increased by the DFPP levels. The plasma antioxidant activity was increased (P > 0.05) with the addition of DFPP. The DFPP improved (P < 0.01) microbial protein synthesis. The supplementation of DFPP and urea increased (P < 0.05) milk fat, whereas milk yield and 3.5% fat corrected milk were only increased (P < 0.05) by the DFPP supplementation. Based on these results, addition of DFPP at 400 g/animal per day with urea at 100 g/animal per day improved rumen fermentation, plasma antioxidant activity, milk yield and milk fat percentage.

Short-Term Adaptation of Dairy Cattle Production Parameters to Individualized Changes in Dietary Top Dress.

Simple Summary“Short-Term Adaptation of Dairy Cattle Production Parameters to Individualized Changes in Dietary Top Dress” focuses on feeding dairy cattle varying amounts of top dressed corn grain, soybean meal, or grass hay in order to obtain data on individual cow responses to be utilized for future development of individualized dairy precision feeding models. Precision feeding systems aimed at feeding dairy cattle individually to increase feed efficiency could contribute to profitability of dairies. The information provided in this study includes considerations of how we should design such systems.Immediate and short-term changes in diet composition can support individualized, real-time interventions in precision dairy production systems, and might increase feed efficiency (FE) of dairy cattle in the short-term. The objective of this study was to determine immediate and short-term effects of changes in diet composition on production parameters of dairy cattle fed varying amounts of top dressed commodities. A 4 × 4 replicated Latin square design was used to evaluate responses of twenty-four Holstein cows fed either no top dress (Control) or increasing amounts of: corn grain (CG), soybean meal (SBM), or chopped mixed grass hay (GH) top dressed on a total mixed ration (TMR) over four, 9-day periods. Throughout each period, top dressed commodities were incrementally increased, providing 0% to 20% of calculated net energy of lactation (NEL) intake. Measured production responses were analyzed for each 9-d period using a mixed-effects model considering two different time ranges. Samples collected from d 3 and 4 and from d 7 and 8 of each period were averaged and used to reflect “immediate” vs. “short-term” responses, respectively. In the immediate response time frame, control fed cows had lower milk yield, milk fat yield, and milk true protein yield than CG and SBM supplemented animals but similar responses to GH supplemented animals. Milk fat and protein percentages were not affected by top dress type in the immediate term. In the short-term response time-frame, GH supplemented animals had lower DMI and milk fat yield than all other groups. Control and GH supplemented cows had lower milk yield than CG and SBM fed cows. In the immediate response time frame, FE of SBM supplemented cows was superior to other groups. In the short-term time frame, FE of GH and SBM groups was improved over the control group. Results suggest that lactating dairy cows show rapid performance responses to small (<20% NEL) changes in dietary composition, which may be leveraged within automated precision feeding systems to optimize efficiency of production. Before this potential can be realized, further research is needed to examine integration of such strategies into automatic feeding systems and downstream impacts on individual animal FE and farm profitability.

Polymorphisms of SORBS1 Gene and Their Correlation with Milk Fat Traits of Cattleyak.

Simple SummaryIncreasing milk fat rate has a good effect on the milk quality of cattleyak. SNPs can help us find potential molecular markers for the milk fat traits of cattleyak, and they can be screened according to molecular markers when they are young. It provides a reference for cultivating high milk fat cattle population in the future. The results of this study suggest that the SORBS1 gene polymorphism is closely related to the milk fat traits of cattleyak, which could be used as a candidate genetic marker for milk fat trait selection in cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak. It has a certain reference value for the research and improvement of milk quality.This study aimed to find the SNPs in the SORBS1 gene of cattleyak, analyze the relationship between its polymorphisms and the milk fat traits, and find potential molecular markers for the milk fat traits of cattleyak. The polymorphism of the SORBS1 gene in 350 cattleyak from Hongyuan County (Sichuan, China) were detected by PCR and DNA sequencing, and the correlation between these SNPs and the milk production traits of cattleyak was analyzed. The results showed that there were nine SNPs in the CDS and their adjacent non-coding regions of the SORBS1 gene, and all SNPs have three genotypes. The correlation analysis found that the genotypes with superior milk fat traits in the other eight alleles were homozygous genotypes with a high genotype frequency except the g.96284 G > A (c.3090 G > A) (p < 0.05). However, at locus g.96284 G > A, the milk fat percentage, monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) of the GA genotype were significantly higher than that of GG and AA genotypes (p < 0.05). Among these SNPs, three SNPs (g.6256 C > T (c.298 C > T), g.24791 A > G (c.706 A > G) and g.29121 A > G (c.979 A > G)) caused the amino acids change. The genotypes of the three SNPs consist of three haplotypes and four diplotypes. The amino acid mutation degree of diplotype H1–H1 (CCAAAA) was the highest, and its milk fat percentage, MUFAs, PUFAs and SFAs were also the highest (p < 0.05). Taken together, we found nine SNPs in the SORBS1 gene that are closely related to the milk fat traits of cattleyak. Moreover, the mutation of amino acids caused by SNPs had positive effects on the milk fat traits of cattleyak. H1-H1 is the dominant diplotype which significantly related to the milk fat traits of cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak.

Reducing milking frequency from twice to once daily as an adjunct treatment for ketosis in lactating dairy cows—A randomized controlled trial

This randomized controlled trial investigated the effects of temporarily reducing milking frequency (MF) on the resolution of ketosis and milk production in dairy cows in early lactation. To detect ketosis [blood β-hydroxybutyrate (BHB) ≥1.2 mmol/L], Holstein cows were screened daily from 3 to 16 d in milk using a cow-side meter. Cows diagnosed with ketosis (n = 104) were randomly assigned to twice-daily milking (TDM) or reduced to once-daily milking (ODM) for 2 wk, then returned to twice-daily milking. Both treatment groups received a 5-d treatment of an oral propylene glycol drench (PG; 300 g) beginning on the afternoon of the diagnosis; cows received additional 5-d PG treatments if they had a ketotic test result (blood BHB ≥1.2 mmol/L) at least 4 d after finishing the first PG treatment. Blood BHB tests were conducted for the first 3 d after ketosis diagnosis, and then once every 3 d for 21 d of trial (DOT). Milk and milk component data were collected weekly for 15 wk following trial enrollment. The ODM group showed rapidly and markedly decreased blood BHB concentrations (primiparous cows: 1 DOT, 0.92 ODM vs. 1.22 TDM, 15 DOT, 0.55 vs. 0.81 mmol/L; multiparous cows: 1 DOT, 1.01 vs. 1.40, 15 DOT, 0.78 vs. 1.65 mmol/L). In addition, a logistic regression model indicated that ODM cows were less likely to have blood BHB concentrations ≥1.2 mmol/L [primiparous cows: 3 DOT: ODM 1% (95% confidence interval: 0-10%) vs. TDM 43% (30-58%), 15 DOT ODM 0% (0-0.2%) vs. TDM 22% (13-36%); multiparous cows: 3 DOT: ODM 33% (24-44%) vs. TDM 59% (48-69%), 15 DOT ODM 20.9% (13-31%) vs. TDM 64% (53-74%)]. The proportion of ODM cows that required additional treatments of PG were substantially lower than the TDM group (ODM: 39%; TDM: 64%) than the TDM cows during the initial 21-d period. However, during the 2-wk treatment period, cows in the ODM group produced 26% less milk and 25% less energy-corrected milk than the TDM cows. During wk 3 to 15, when all cows were milked twice daily, ODM cows produced less milk (-14%) and energy-corrected milk (-12%) compared with the TDM group. Milk protein percentage was greater, and milk fat percentage and linear score tended to be greater in the ODM group over 15 wk. In conclusion, a 2-wk reduction of MF in ketotic cows from twice to once daily with treatment with PG resolved ketosis and decreased blood BHB concentrations more effectively than treating TDM cows with PG alone. However, the 2-wk MF reduction had immediate and long-term (up to 13 wk after cessation of MF reduction) negative effects on milk production.

Sequence Variation in the Bovine Lipin-1 Gene (LPIN1) and Its Association with Milk Fat and Protein Contents in New Zealand Holstein-Friesian × Jersey (HF × J)-cross Dairy Cows.

Simple SummaryLipins are a family of proteins involved in lipid metabolism through their phosphatidate phosphatase and transcriptional co-activator activities. Of the three family members identified, lipin-1 is highly upregulated in the bovine mammary gland during lactation, and has been implicated in regulating milk production, albeit with inconsistent results in different breeds of cattle in studies. Accordingly, its role in regulating milk synthesis is not well understood. In this study, we used polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analyses to investigate variation in the bovine lipin-1 gene in New Zealand Holstein-Friesian × Jersey-cross dairy cows and found that variation in the sixth coding exon was associated with milk fat percentage and protein percentage. This suggests that lipin-1 regulates the synthesis of milk fat and milk protein.Lipin-1 is known to play a regulatory role in tissues that function in lipid metabolism. In dairy cows, the lipin-1 gene (LPIN1) is highly expressed in the mammary gland, but its function in milk production is less understood. In this study, we used PCR-single strand conformation polymorphism analysis to investigate sequence variation in three regions of bovine LPIN1 in New Zealand Holstein-Friesian × Jersey (HF × J)-cross dairy cows, including part of the 5′ non-coding region, the region containing the LPIN1β-spliced exon, and the sixth coding exon that encodes the putative transcriptional activating domain of the protein. No variation was found in the LPIN1β-spliced exon, but two sequence variants containing one single nucleotide polymorphism (SNP) were identified in the 5′ non-coding region and four sequence variants containing four non-synonymous SNPs were identified in the sixth coding exon. Among the three common variants of the sixth coding exon, variant C was found to be associated with an increase in milk fat percentage (presence 4.96 ± 0.034% vs. absence 4.81 ± 0.050%; p = 0.006) and milk protein percentage (presence 4.09 ± 0.017% vs. absence 3.99 ± 0.025%; p = 0.001), but no associations (p > 0.01) were detected for milk yield. These results suggest that variation in LPIN1 affect the synthesis of fat and proteins in milk and has potential as a gene-marker to improve milk production traits.

The role of melatonin implantation and the associated effect of insulin-like growth factor-1 on milk composition of Barki ewes

Context Manipulation of milk composition in lactating ewes represents an important mechanism by which sheep breeders can improve profits through increased milk prices for cheese making and higher lamb growth rates. To this end, melatonin implantation may affect milk composition by alleviating reproductive seasonality and augmenting insulin like growth factor-1 (IGF-1). Aims This research aimed to evaluate the effects of melatonin administration on hormone levels and milk composition, and to determine its potential to manipulate milk composition of lactating Barki ewes. Methods Fifty lactating Barki ewes were divided into two groups of 25. One group received 18 mg melatonin in a single implant at 40 days after delivery, and the other group served as an untreated control. Over the following 8 weeks, milk components (fat, protein, lactose and total solids percentages), milk energy value, and blood serum hormones including IGF-1 were measured. Key results Melatonin implantation increased (P &lt; 0.05) IGF-1 concentration, which showed continued elevation (P &lt; 0.05) throughout the treatment period (from Day 14 to Day 56) relative to the control. Analysis of milk composition of implanted ewes revealed higher (P &lt; 0.05) milk fat, protein, lactose and total solids percentages as well as milk energy value than in milk of control ewes. Conclusion An integrated effect of melatonin and IGF-1 successfully improved milk composition of lactating Barki ewes. Implications Melatonin implantation can be used to improve milk composition of lactating Barki ewes, potentially increasing profits from cheese making and lamb production.

Associations between polymorphisms of SLC22A7, NGFR, ARNTL and PPP2R2B genes and Milk production traits in Chinese Holstein

BackgroundOur preliminary work confirmed that, SLC22A7 (solute carrier family 22 member 7), NGFR (nerve growth factor receptor), ARNTL (aryl hydrocarbon receptor nuclear translocator like) and PPP2R2B (protein phosphatase 2 regulatory subunit Bβ) genes were differentially expressed in dairy cows during different stages of lactation, and involved in the lipid metabolism through insulin, PI3K-Akt, MAPK, AMPK, mTOR, and PPAR signaling pathways, so we considered these four genes as the candidates affecting milk production traits. In this study, we detected polymorphisms of the four genes and verified their genetic effects on milk yield and composition traits in a Chinese Holstein cow population.ResultsBy resequencing the whole coding region and part of the flanking region of SLC22A7, NGFR, ARNTL and PPP2R2B, we totally found 20 SNPs, of which five were located in SLC22A7, eight in NGFR, three in ARNTL, and four in PPP2R2B. Using Haploview4.2, we found three haplotype blocks including five SNPs in SLC22A7, eight in NGFR and three in ARNTL. Single-SNP association analysis showed that 19 out of 20 SNPs were significantly associated with at least one of milk yield, fat yield, fat percentage, protein yield or protein percentage in the first and second lactations (P < 0.05). Haplotype-based association analysis showed that the three haplotypes were significantly associated with at least one of milk yield, fat yield, fat percentage, protein yield or protein percentage (P < 0.05). Further, we used SOPMA software to predict a SNP, 19:g.37095131C > T in NGFR, changed the structure of NGFR protein. In addition, we used Jaspar software to found that four SNPs, 19:g.37113872C > G,19:g.37113157C > T, and 19:g.37112276C > T in NGFR and 15:g.39320936A > G in ARNTL, could change the transcription factor binding sites and might affect the expression of the corresponding genes. These five SNPs might be the potential functional mutations for milk production traits in dairy cattle.ConclusionsIn summary, we proved that SLC22A7, NGFR, ARNTL and PPP2R2B have significant genetic effects on milk production traits. The valuable SNPs can be used as candidate genetic markers for genomic selection of dairy cattle, and the effects of these SNPs on other traits need to be further verified.

California Test to Detect of Mastitis Incidence, Parity and Stage of Lactation to Indicators to Milk Composition in Iraqi Buffaloes

The research was carried out in the Hashemite district (25 km southwest of Babil Governorate) on 150 female Iraqi buffaloes for the period from 2/7/2019 to 1/6/2020, with the aim of studying the relationship between the California test and a number of milk traits. The results showed a significant effect (P≤0.01) of the reproductive cycle sequence in the CMT and the proportions of both fat and protein in the milk, as the California test scores reached the maximum for female buffaloes in the fourth milk cycle (1.80 degrees). There was a highly significant variation (P≤0.01) in the percentage of fat according to the different production cycle, and the highest percentage of fat in milk was in female buffaloes during the first milk cycle (6.59%). It was found that the milk production stage had a significant effect on the CMT degrees, as the CMT degree increased with the progression of the milking stage, until it reached during the third stage of the milk production cycle (1.59) and was lower in the first production cycle (1.48). The percentage of fat was significantly affected (P≤0.01) by the stage of milk production (Table 1), as it reached the highest (6.86%) in the third stage of the production season and the lowest (5.98%) during the second stage. It is concluded from the research that the California test is an indicator of some components of milk and that the degree of the California test and the percentage of fat are affected by the sequence of birth and the stage of milk production in buffaloes.

The Relationship Between The PIT-1 Gene at The Rate of Daily Milk Production and Some of Its Components in Buffaloes

This study was conducted at the College of Agriculture/University of Al-Muthanna for the period between 1/10/2020 until 30/6/2020, 60 buffaloes were used in the experiment with the aim of determining the genotypes and their distribution ratios for the PIT-1 gene. The genotypes were altered (P<0.01), which amounted to 18.52 and 81.48 respectively, and the allelic frequency was 0.10 and 0.90 for each of the two alleles A, B, respectively. Daily milk production and fat percentage were not significantly affected, milk protein percentage was significantly affected (P<0.05) in the eleventh week, reaching a maximum of 3.88±0.28 (BB), as well. Significant differences (P<0.05) were found in the percentage of genetic non-fatty solids in the first week of the study, with a maximum of 23.28 (BB). BB genotype.

Meta-analysis of rumination behavior and its relationship with milk and milk fat production, rumen pH, and total-tract digestibility in lactating dairy cows

Time spent ruminating is affected by diet and affects the rumen environment. The objective of the current study was to conduct a meta-regression to characterize the variation in rumination time and its relationship with milk and milk fat yields and variables mechanistically associated with milk fat synthesis, including rumen pH and total-tract digestibility. The analysis included 130 journal articles published between 1986 and 2018 that reported 479 treatment means from lactating Holsteins cows during established lactation. Milk yield averaged 34.3 kg/d (range 14.2-52.1 kg/d), milk fat averaged 3.47% (range 2.20-4.60%), and rumen pH averaged 6.1 (range 5.3-7.0). Rumination observation systems were categorized into 6 groups, but there was little difference in average rumination time among systems. The total time spent ruminating averaged 444 min/d (range 151-638 d) and occurred in 13.8 bouts/d (range 7.8-17.4 bouts/d) that averaged 32.7 min (range 20.0-48.1 min). Bivariate regressions were modeled to include the random effect of study, and correlations were evaluated through the partial R2 that excluded variation accounted for by the random effect. Rumination time was quadratically increased with increasing milk fat yield (partial R2 = 0.27) and milk fat percent (partial R2 = 0.17). Rumination was also increased with increasing milk yield, dry matter intake, and rumen pH, and was quadratically related to dietary neutral detergent fiber (NDF) and total-tract NDF digestibility (partial R2 = 0.10-0.27). Similar relationships were observed for rumination per unit of dry matter and NDF intake. The best-fit multivariate model predicting total rumination time included milk yield, milk fat yield, and concentration and accounted for 37% of the variation. Total-tract digestibility was available for 217 treatment means; when included in the model, the partial R2 increased to 0.41. Last, principal component analysis was conducted to explore the relationship among variables. The first 2 principal components in the broad analyses explained 36.7% of the 39 variables evaluated, which included rumination bouts and time spent ruminating. In conclusion, rumination time was related to milk fat across a large number of studies, although it explained only a limited amount of the variation in milk fat.

505 Late-Breaking: Ruminal Microbiota, Inflammation Cytokines, and Performance of High-yield Dairy Cows Supplemented with Saccharomyces Cerevisiae Culture

Abstract Dramatic increases in milk yields in recent decades have created challenges in terms of rumen pH and microbial health which ultimately impact dairy cow health. The objective of this study was to assess the effects on ruminal pH, Volatile Fatty Acid (VFA), microbiota, inflammation, and performance of high-yield dairy cows by supplementing Saccharomyces cerevisiae culture (SC). Forty Holstein cows were divided into two groups based on their milk yield, days of milk, and parity fed the same basal ration diet that did or did not contain 100 g of SC /cow per day. Individual dry matter intake (DMI) and milk yield were recorded each day. Rumen fluid and milk samples were collected after 2 hours of morning feeding at intervals of 15 days during the experiment period. The data showed that rumen pH was increased by 0.19 (P = 0.09) when SC was supplemented than no SC was provided. SC-supplemented cow consumed 0.28 kg (P &amp;lt; 0.05) extra DM/d. Those supplemented with SC produced 1.36 kg (P &amp;lt; 0.05) more milk/cow per day than did non-supplemented cows. Milk fat percentage was higher (4.11 vs. 3.96%) for cows receiving SC. There were no differences in milk protein percentage. Rumen fluid VFA concentration was not statistically affected by SC but was numerically higher acetic and lower propionic for supplemented cows. The blood of the SC group with lower inflammation cytokines and somatic cell count (SCC). SC-supplemented cows had a greater relative abundance of Prevotellaceae, Succinivibrionaceae, Fibrobacteraceae, Lactobacillaceae, and lower relative abundance of Spirochaetaceae, Methanobacteriaceae, Enterobacteriaceae than the unsupplemented cows. It had greater functions on xylanolysis, fermentation, cellulolysis in the rumen in terms of the KEGG function prediction analysis. This study demonstrated that high-yield lactation cows receiving supplemental SC produced more milk and potentially reduced the inflammation and enhanced rumen cellulolysis bacteria growth.

PSXI-2 Genome-Wide association study and possibilities for genomic selection of Simmental cattle breed in Russia

Abstract The implementation of genomic selection methods in dairy cattle is limited due to the size of the reference population, quantitative traits variability and genetic structure of population. The Simmental cattle and related breeds in Russia occupy the third place by registered cows - 87.6 thousand, and are bred from the western borders of central Russia to Yakutia in Siberia. The study aim was to search for QTL using as a pseudo phenotype sires’ EBV to validate the effectiveness of genomic assessments for Simmental cattle in Russia. Reference group based on 358 bulls from different Russian regional populations was formed. By the dataset of 61976 cows, using BLUP Animal Model approach, animals’ EBV were calculated. The GBLUP procedure was used to get genomic prediction (DGV). Genotype quality control selected of 37143 SNPs. GWAS analysis was perform by Plink 1.90. To prove DGV we used verification procedure to comparison with EBV in training population dataset that showed slightly moderate repeatability for 305-milk yield - 37.6%, milk fat - 39.8% and milk protein - 43.6%. Significant SNPs associated with bulls EBV according to milk production and fertility traits revealed for: 305-milk yield on BTA5 (ACO2,p=0.0005), BTA29 (NAP1L4, P = 0.00004; KCNQ1, P = 0.00004); fat percentage on BTA3 (ROR1, P = 0.0003), BTA14 (CRH, P = 0.0003; TRIM55, P = 0.0003; DNAJC5B, P = 0.0003; REX2, P = 0.0020; ZFHX4, P = 0.0020) BTA17 (TLR2, P = 0.0011); days open on BTA1 (TNIK, P = 0.0007; FNDC3B, P = 0.0007), BTA21 (IGF1R, P = 0.0002). Using Cattle QTL Database, the identified genes were associated with milk yield, fat and protein percentage, protein yield, somatic cell score, protein-to-fat ratio, stearic fatty acid content, calving ease, daughter pregnancy rate, stillbirth and inseminations per conception. GWAS results identified significant SNPs associated with milk production and fertility traits that will allow in the nearest future improve reliability for genomic prediction of young bulls and boost genetic trend in the Russian Simmental cattle population. The study was funded by RFBR within project No.17-29-08030

PSVIII-14 Effect of Certillus, a direct-fed microbial, on milk yield, milk components, and feed intake in primi- and multiparous lactating Holstein cows

Abstract To determine the effect of Certillus on milk production, milk components and feed efficiency, primiparous (n = 13) and multiparous (n = 12) Holstein cows were assigned to one of two dietary groups starting from 8 to 120 days of lactation. The controls (n = 13) received regular TMR ration, and treated cows (n =12) received control TMR plus 2 x 109 cfu/head of Certillus (Church &amp; Dwight Co., Inc., Waukesha, WI). Cows were housed in an open-air free-stall barn with 16 Insentec electronic feeders (8 feeders/group) to record daily feed events and intake (DMI). Cows were provided with ad libitum TMR fed twice daily and were milked twice daily. Milk samples were taken weekly during successive a.m./p.m. milkings and analyzed for percentage milk fat, protein, lactose, and milk urea nitrogen (MUN). Data were analyzed using a repeated-measures 2 x 2 factorial ANOVA. Daily milk production (4%FCM) was influenced (P &amp;lt; 0.05) by treatment x parity, week and parity, averaging 11% greater (P &amp;lt; 0.05) in Certillus-fed than control cows. Milk fat percentage increased (P &amp;lt; 0.005) from 4.02 to 4.41 + 0.09% with Certillus feeding. Milk lactose was influenced (P &amp;lt; 0.05) by week and treatment x parity. Milk protein was affected by week (P &amp;lt; 0.001) only. Certillus decreased (P &amp;lt; 0.05) MUN levels such that MUN was 1.0 mg/dL greater (P &amp;lt; 0.001) in Certillus-fed than control cows. Feed intake was reduced by 9% (P &amp;lt; 0.01) and feed efficiency (kg 4%FCM/kg DMI) was improved by 14% (P &amp;lt; 0.05) in Certillus-fed versus control cows. We conclude that Certillus may hold potential as an effective direct-fed microbial to increase feed efficiency and milk production.

Relationships of αs1-casein (CSN1S1) and β-casein (CSN2) genotypes and their association with milk quality and coagulation properties in Bulgarian Brown cattle

The aim of the present investigation was to establish the relationships of αs1-casein (CSN1S1) and β-casein (CSN2) genotypes in Bulgarian Brown cattle and to evaluate their association with milk quality and milk coagulation properties. Milk proteins’ polymorphism was found out in 155 tissue samples from cows reared at 4 farms. Innovative protocols and techniques were used for determination of genetic polymorphism of αs1-casein (CSN1S1) and β-casein (CSN2) in Brown cattle. After collection, tissue samples were shipped to the University in Padova, Italy for PCR-RFLP analysis. The analysis of milk composition was done in the lab of the Agriculture Institute – Stara Zagora on Lactoscan ultrasound milk analyzer, whereas coagulation properties of individual milk samples were evaluated on a Computerized Renneting Metter – Polo Trade, Italy. During the study, the following parameters were studied: milk fat and protein contents (%), rennet coagulation time (RCT, min), curd firmness (а30, mm) and curd firming time (k20, min). Heterozygous cows for both studied milk proteins: CSN1S1 and CSN2, had higher milk fat and milk protein percentages, 4.71% fat and 3.45% protein in genotype ВС of CSN1S1 and 5.00% fat and 5.33% protein in genotype АВ of CSN2. The milk of cows from different CSN1S1 and CSN2 genotypes was outlined with moderate curd firmness and good coagulation time. Homozygous cows for both studied milk proteins had higher curd firmness (32.31 mm) for the ВВ genotype of CSN1S1 and 31.29 mm for the АА genotype of CSN2.