Milk Production Traits Research Articles

Novel association between polymorphism of the AQP3 gene and milk production traits in Bos indicus

Novel association between polymorphism of the AQP3 gene and milk production traits in Bos indicus

Polymorphisms of Fatty Acid Synthase Gene and their Association with Milk Production Traits in Chinese Holstein Cows

Polymorphisms of Fatty Acid Synthase Gene and their Association with Milk Production Traits in Chinese Holstein Cows

Genome-Wide Association Study for Test-Day Milk Yield, Proteins, and Composition Traits of Crossbred Dairy Cattle in Ethiopia.

Identifying genetic regions and candidate genes that influence milk production traits is critical for understanding genetic inheritance and improving both the quality and quantity of milk in dairy cattle. Crossbred dairy cattle significantly contribute to increasing milk production and ensuring food security in the middle- and high-altitude regions of Ethiopia. However, the genetic architecture underlying their milk yield and composition traits has not yet been thoroughly investigated. This study conducted a genome-wide association study (GWAS) on 308 crossbred dairy cows from central, northeastern, and southern Ethiopia to identify genetic markers associated with key milk production traits. Using high-density SNP chip data and the fixed and random model circulating probability unification (Farm CPU) method via the Memory-efficient, Visualization-enhanced, and Parallel-accelerated R package (rMVP) (Version 1.0.7.), we analyzed traits including test-day milk yield (TDMY), total protein (TP), casein (CN), whey (W), protein percentage (P), fat percentage (F), lactose percentage (L), total solids (TS), density (D), solids-not-fat (SNF), salt (S), and freezing point (FP). This study identified 16 significant SNPs associated with these traits, including rs41661899 on Chromosome 6, which was significantly associated with both TP and W, and rs42274954 on Chromosome 12, which was significantly associated with CN. Eight SNPs, such as rs43560693, rs109098713, rs111029661, rs134499665, rs133908307, rs133627532, rs42098411, and rs110066280, were found across multiple chromosomes (8, 10, 14, 15, 19, 21, 26, and 28, respectively) and were significantly associated with milk P. Additionally, SNPs rs110844447 and rs135995768 on Chromosomes 6 and 14 were significantly associated with D and FP, respectively. Three SNPs, including rs109564259, rs135552551, and rs41620904 on Chromosomes 6, 11, and 24, were significant associations with S. Candidate genes identified near and within these SNPs include TRAM1L1, DIAPH3, PEBP4, WDR89, BCAS3, RALGAPA1, HABP2, NRG3, HPSE, PCDH7, LINC02579, TRNAS-GGA, and OR5CN1P. These findings enhance our understanding of the genetic architecture of milk-related traits in Ethiopian dairy cattle and highlight the potential for marker-assisted selection to improve milk production and composition in breeding programs.

Genetic parameters for milk production and body-conformation traits in Dairy Gir cattle

Context Gir is a tropically adapted breed of Bos taurus indicus cattle that has been intensively selected for milk production in Brazil. Selection programs also consider body-conformation traits because these have been associated with health, welfare, and cow longevity, thus affecting productivity. Aims This study focused on Gir cattle to estimate genetic and phenotypic parameters for body-conformation traits, as well as their correlations with milk production traits. Methods Body-conformation traits were classified as ‘frame’, ‘foot and leg’, or ‘mammary system’ traits. The dataset contained 1105 cows recorded with body-conformation traits and 38 996 records of 305-day cumulative milk yield, from 24 489 Gir cows. The pedigree file included 38 571 animals, of which 1593 were genotyped using six different single-nucleotide polymorphism panels. After genotyping imputation, and quality control, 42 105 polymorphisms were available for analyses. Univariate and bivariate animal models, using Bayesian approach via the Gibbs sampling algorithm, were used to estimate genetic parameters, benefiting from both genotypes and pedigree data. Key results The heritabilities for body-conformation traits ranged from a low of 0.08 ± 0.04 to a medium value of 0.35 ± 0.07, and the heritability for milk production was 0.23 ± 0.01. We identified unfavourable genetic correlations between milk yield and udder depth (0.63 ± 0.11) as well as body height (0.31 ± 0.13). In contrast, there was a favourable genetic correlation between milk yield and rear udder width (0.61 ± 0.14). Conclusion The heritability estimates confirmed the possibility of selecting animals for milk yield and body conformation traits related to the frame and mammary system categories. Based on the estimated genetic correlations, considerable importance should be given to the emphasis on selection for increased milk yield, because in the long term, this may promote undesirable changes in some type traits as body height and udder depth. Implications This information is relevant to selective breeding of Gir to enhance tropical milk production.

Effect of age at first insemination on the milk production traits of dairy cow

Effect of age at first insemination on the milk production traits of dairy cow

A systematic review of effect of calving season and parity as non-genetic factors on milk production traits of cattle

A systematic review of effect of calving season and parity as non-genetic factors on milk production traits of cattle

Genetic polymorphism in prolactin gene and its association with milk production traits of Sahiwal cattle in Assam

Genetic polymorphism in prolactin gene and its association with milk production traits of Sahiwal cattle in Assam

INFLUENCE OF CALVING SEASON OF COWS ON THEIR PRODUCTIVITY UNDER ORGANIC AND CONVENTIONAL MILK PRODUCTION

The aim of the research was to study the impact of the first calving season of Simmental cows on their future milk productivity and reproductive capacity in conditions of both organic and conventional milk production.
 Research materials and methods. The research was conducted in Simmental breed herds of PE "Galex-Agro" (organic milk production, n = 272) and STOV "Myroslavel-Agro" (conventional milk production, n = 120) in the Zviahel district of Zhytomyr region, Ukraine. First-calving cows in the two farms were categorized into four groups based on the calving season: Group I – Winter (n = 83 and 42 cows in PE "Galex-Agro" and STOV "Myroslavel-Agro" respectively); Group II – Spring (59 and 26);Group III (45 and 12); Group IV (85 and 40 cows).
 Research results. First-calving cows in organic production demonstrated a higher expression of quantitative traits of milk productivity, regardless of the calving season, compared to their counterparts in conventional conditions, albeit with slightly lower qualitative traits. However, statistically significant differences were found only in 305-day milk yield between autumn-calving cows in favor of first-calving cows from PE "Galex-Agro."
 It is worth noting that, in both farms, the first calving in the autumn season was found to be the most favorable, while the summer season was the least favorable, which provides grounds for planning calving in the autumn period. Our research results indicate that animals under organic management, regardless of the calving season, exhibited statistically significantly (P < 0.01–0.001) older age at first calving and longer calving intervals. No statistically significant intergroup differences were found in other reproductive traits.
 The season of first calving in both organic and conventional milk production conditions accounted for 0.3 to 4.7% and 0.2 to 3.3% of the total phenotypic variability in milk productivity traits, as well as 1.0 to 2.9% and 0.6 to 2.5% of the reproductive capacity. Statistically significant effects of the calving season were only observed in PE "Galex-Agro" and exclusively on productivity traits, including lactation duration (3.2%), 305-day milk yield (4.3%), milk fat content (4.7%), milk protein content (4.3%), milk fat, and protein content (4.7%), as well as the duration of dry period (2.9%) (P < 0.05–0.001).
 Conclusion. Our research results highlight the importance for specialists in both farms to pay attention to the seasonality of first calving in cows and, if possible, take these aspects into account when planning breeding and technological measures in the farms.

MILK PRODUCTIVITY OF COWS OF THE UKRAINIAN RED-AND-WHITE DAIRY BREED DEPENDS ON THE ORIGIN AND COMPATIBILITY OF THE BULLS

We studied the effectiveness of the bulls selection to the cows of the Ukrainian Red-and-White dairy breed (n = 490 mother-daughter pairs) different bloodlines and related groups. The level of milk productivity of first-borns cows (n = 490 mother-daughter pairs) for 305 days of the first lactation, obtained as a result of the compatibility of the bulls. The parents of the first-borns cows were four breeding bulls (bloodline Regal 352882, RG Valiant 1650414 and R. Sovereign 198998) of the Ukrainian Red-and-White dairy breed and one bull (Jornado Red 114386106, RG Chief 1427381) of the Holstein breed, and their mothers – from 11 bulls of three origin bloodlines (Dynemik 359742, Leader 1926780 and Hanover 1629391) and 4 related groups. A total of 29 combinations of interbloodline selection were investigated. The highest level of milk productivity was characterized by the daughters of bull Viter 4444 of the bloodline Regal 352882 (7191.5 ± 75.90), Jornado Red 114386106 of the Holstein breed of foreign selection, which belonged to the related group Chief 1427381 (the milk yield for 305 days of the first lactation was 7188.7 ± 31.05 kg), and Artek 344 related group Valiant 1650414 (the yield for 305 days of the first lactation was 7052.5 ± 75.51 kg). A statistically significant difference was established between milk yield indicators for 305 days of the first lactation between the groups of cows of the bull Jornado Red (related group Chief 14273381) and Luchnov 471 (r. g. R. Sovereign 198998) – +380 kg (td = 4.22 p < 0.001) in favor Jornado Red. Between cows of the bull Viter 4444 (bloodline Regal 352882) and Luchnov 471 (R. Sovereign 198998) – +383 kg (td = 3.38 p < 0.001) in favor of Viter 4444. Animals of the bulls Kanzler and Viter 4444 have the highest fat content in milk (3.71%), and cows of the related groups Valiant 1650414 characterized by the lowest fat content in milk (3.68%). A statistically significant difference was established between the amount of total milk fat and protein in the milk of cows of different bulls.
 A total 20 successful combinations of bulls were found, the first-borns cows of which were characterized by an increased milk yield on average across all successful compatibility by +96 kg (1.5%), milk fat yield – by +6,1 kg (2.3%) and total protein – by +5.3 kg (2.3%) from the average level of phenotypic manifestation of milk productivity traits of the daughters of all 5 evaluated bulls. The increasing of daughters milk yield of some successful combinations was from +42 kg (0.6%, sire Jornado 114386106 RG Chief 1427381) up to +296 kg (4.1%, sire Viter 4444,), milk fat from +2 kg (0.7%, sire Artek 344, RG Valiant) up to +8 kg (3%, sire Viter 4444) and protein from +1 kg (0.4%, sire Artek 344) up to +12 kg (5%, sire Viter 4444). The data, which we received, confirm the influence of the origin of cows by father on the level of their milk productivity and the high combining ability of individual improver bulls with the mothers of other genealogical formations.

Association of Variants in Innate Immune Genes TLR4 and TLR5 with Reproductive and Milk Production Traits in Czech Simmental Cattle.

Bovine genes TLR4 and TLR5, which encode antibacterial toll-like receptors, were screened for polymorphisms in Czech Red Pied (Czech Simmental) cattle to identify variants associated with reproduction, udder health, and milk production traits. Variants were discovered by hybrid resequencing of 164 bulls using HiSeq X-Ten and PacBio technologies and then individually genotyped. Nominal p-values < 0.05 for associations were detected in 18 combinations between 14 polymorphisms and 15 traits using one-way analysis of variance (ANOVA). The TLR4 variants g.610C>T (rs43578094) and g.10310T>G (rs8193072) in reference AC000135.1 were strictly associated with the index of early reproductive disorders and maternal calving ease, respectively, at false discovery rate (FDR) < 0.05. A highly permissive false discovery rate cutoff of 0.6 separated seventeen combinations in both genes comprising eight positives. In the case of the TLR4 variant g.9422T>C (rs8193060), indications were obtained for the association with as many as four reproductive traits: incidence of cystic ovaries, early reproductive disorders, calving ease, and production longevity. The permissive FDR interpretation for the TLR5 data indicated associations with cyst incidence and early reproduction disorders with maternal calving ease. Moreover, three TLR5 polymorphisms correlated with milk production traits. The discrepancy of the observed associations with the predicted impacts of the SNPs on protein function points to the role of haplotypes. Nevertheless, this question should be resolved on a larger scale. The observed associations are endorsed by independent evidence from the published functional roles in other species and by the published QTL mapping data.

Descriptive Statistics and Genome-Wide Copy Number Analysis of Milk Production Traits of Jiangsu Chinese Holstein Cows.

Milk production traits are the most important quantitative economic traits in dairy cow production; improving the yield and quality of milk is an important way to ensure the production efficiency of the dairy industry. This study carried out a series of in-depth statistical genetics studies and molecular analyses on the Chinese Holstein cows in the Jiangsu Province, such as descriptive statistics and copy number variation analysis. A genetic correlation, phenotypic correlation, and descriptive statistical analysis of five milk production traits (milk yield, milk fat percentage, milk fat yield, milk protein percentage, and milk protein yield) of the dairy cows were analyzed using the SPSS and DMU software. Through quality control, 4173 cows and their genomes were used for genomic study. Then, SNPs were detected using DNA chips, and a copy number variation (CNV) analysis was carried out to locate the quantitative trait loci (QTL) of the milk production traits by Perl program software Penn CNV and hidden Markov model (HMM). The phenotypic means of the milk yield, milk fat percentage, milk fat mass, milk protein percentage, and milk protein mass at the first trimester were lower than those at the other trimesters by 8.821%, 1.031%, 0.930%, 0.003%, and 0.826%, respectively. The five milk production traits showed a significant phenotypic positive correlation (p < 0.01) and a high genetic positive correlation among the three parities. Based on the GGPBovine 100 K SNP data, QTL-detecting research on the fist-parity milk performance of dairy cows was carried out via the CNV. We identified 1731 CNVs and 236 CNVRs in the 29 autosomes of 984 Holstein dairy cows, and 19 CNVRs were significantly associated with the milk production traits (p < 0.05). These CNVRs were analyzed via a bioinformatics analysis; a total of 13 gene ontology (GO) terms and 20 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly enriched (p < 0.05), and these terms and pathways are mainly related to lipid metabolism, amino acid metabolism, and cellular catabolic processes. This study provided a theoretical basis for the molecular-marker-assisted selection of dairy cows by developing descriptive statistics on the milk production traits of dairy cows and by locating the QTL and functional genes that affect the milk production traits of first-born dairy cows. The results describe the basic status of the milk production traits of the Chinese Holstein cows in Jiangsu and locate the QTL and functional genes that affect the milk production traits of the first-born cows, providing a theoretical basis for the molecular-marker-assisted selection of dairy cows.

Whole-genome resequencing reveals candidate genes associated with milk production trait in Guanzhong dairy goats.

Milk production is one of the most important economic utility of goats. Guanzhong dairy goat is a local dairy goat in Shaanxi Province of China and has high milk yield and quality. However, there are relatively few studies on molecular markers of milk production traits in Guanzhong dairy goats. In this study, we sequenced the whole genomes of 20 Guanzhong dairy goats, 10 of which had high milk yield (HM) and 10 of which had low milk yield (LM). We detected candidate signatures of selection in HM goats using Fst and π-ratio statistics and identified several candidate genes including ANPEP, ADRA1A and PRKG1 associated with milk production. Our results provide the basis for molecular breeding of milk production traits in Guanzhong dairy goats.

Genetic Analysis of Milk Production Traits in the Different Parities of Ethiopian Jersey Dairy Cows

The objectives of this study were to estimate genetic and phenotypic parameters (variances, heritabilities and correlations) of milk production traits in the five consecutive parities

Unraveling the Genomic Association for Milk Production Traits and Signatures of Selection of Cattle in a Harsh Tropical Environment.

A study was designed to identify the genomic regions associated with milk production traits in a dairy cattle population reared by smallholder farmers in the harsh and challenging tropical savanna climate of Bengaluru, India. This study is a first-of-its-kind attempt to identify the selection sweeps for the dairy cattle breeds reared in such an environment. Two hundred forty lactating dairy cows reared by 68 farmers across the rural-urban transiting regions of Bengaluru were selected for this study. A genome-wide association study (GWAS) was performed to identify candidate genes for test-day milk yield, solids-not-fat (SNF), milk lactose, milk density and clinical mastitis. Furthermore, the cross-population extended haplotype homozygosity (XP-EHH) methodology was adopted to scan the dairy cattle breeds (Holstein Friesian, Jersey and Crossbred) in Bengaluru. Two SNPs, rs109340659 and rs41571523, were observed to be significantly associated with test-day milk yield. No significant SNPs were observed for the remaining production traits. The GWAS for milk lactose revealed one SNP (rs41634101) that was very close to the threshold limit, though not significant. The potential candidate genes fibrosin-like 1 (FBRSL) and calcium voltage-gated channel auxiliary subunit gamma 3 (CACN) were identified to be in close proximity to the SNP identified for test-day milk yield. These genes were observed to be associated with milk production traits based on previous reports. Furthermore, the selection signature analysis revealed a number of regions under selection for the breed-group comparisons (Crossbred-HF, Crossbred-J and HF-J). Functional analysis of these annotated genes under selection indicated pathways and mechanisms involving ubiquitination, cell signaling and immune response. These findings point towards the probable selection of dairy cows in Bengaluru for thermotolerance.

Heritability and Repeatability Estimates for Milk Production Traits Using Phenotypic, Pedigree-Based and Genomic Data of Serbian Holstein Cows

Summary This research aims to estimate heritability and repeatability based on the data on milk production traits (MY – milk yield; FY – milk fat yield; FC – milk fat content; PY – milk protein yield and PC – milk protein content) as well as pedigree and genomic information. A total of 6,041 animals were included in the research, while 2,565 of them had data for milk production traits. In order to form a genomic relationship matrix, 58K SNP data were used for a total of 1,491 cows. Several software tools were used in the preparation and analysis of data, which were provided by the Central Breeding Organization, Department of Animal Science, Faculty of Agriculture, University of Novi Sad. PreGSF90, in combination with RENUMF90, was used for quality control of genomic information. Genetic analysis was performed in WOMBAT software by the REML using standard repeatability univariate analysis (BLUPpe) and repeatability models for genomic prediction (GBLUPpe and ssGBLUPpe). In all three analyses, the highest heritability (0.410, 0.378 and 0.389, respectively) and repeatability (0.449, 0.429 and 0.440, respectively) were calculated for FC. Heritability estimates for all other traits were lower. Heritability ranged from 0.158 to 0.185 for MY, from 0.166 to 0.178 for FY, from 0.141 to 0.154 for PY and from 0.135 to 0.221 for PC. Heritability estimates indicate that it is possible to achieve genetic improvement but it is necessary to introduce the best model for prediction of breeding values of cow.

Association of prolactin, interleukin-8 genes polymorphism and the incidence of some diseases with milk production traits in Holstein-Friesian Cows

Association of prolactin, interleukin-8 genes polymorphism and the incidence of some diseases with milk production traits in Holstein-Friesian Cows

Grounding the economic selection index for evaluation and selection of dairy cattle

The aim of the research was to develop a selection index for the evaluation and selection of dairy cattle for increasing milk production and reproductive traits. Materials of the research were data on milk production and reproduction of cows of the Ukrainian Black-and-White dairy breed in commercial farm in Kharkiv region. Studies showed that there was a certain antagonism between milk productivity and reproduction of the Ukrainian Black-and-White dairy cow. The coefficients of phenotypic correlation between milk yield, fat and protein yield and the days open ranged from +0.284 to +0.293. Selection indexes were built, which included protein, fat yield, and days open. The developed selection indexes were characterized by a high relationship with the protein yield (α&lt;0.001), much lower – with the fat yield (α&lt;0.05), while the relationship of the selection indexes with the days open was almost absent. The calculated estimates of correlation and regression coefficients made possible to predict correlated responses of milk production and reproduction traits on selection index. The results showed that the developed selection indexes allow increase the milk production of cows and at the same time to prevent decrease in the level of reproduction.

Identification of genetic associations and functional SNPs of bovine KLF6 gene on milk production traits in Chinese holstein

BackgroundOur previous research identified the Kruppel like factor 6 (KLF6) gene as a prospective candidate for milk production traits in dairy cattle. The expression of KLF6 in the livers of Holstein cows during the peak of lactation was significantly higher than that during the dry and early lactation periods. Notably, it plays an essential role in activating peroxisome proliferator-activated receptor α (PPARα) signaling pathways. The primary aim of this study was to further substantiate whether the KLF6 gene has significant genetic effects on milk traits in dairy cattle.ResultsThrough direct sequencing of PCR products with pooled DNA, we totally identified 12 single nucleotide polymorphisms (SNPs) within the KLF6 gene. The set of SNPs encompasses 7 located in 5′ flanking region, 2 located in exon 2 and 3 located in 3′ untranslated region (UTR). Of these, the g.44601035G > A is a missense mutation that resulting in the replacement of arginine (CGG) with glutamine (CAG), consequently leading to alterations in the secondary structure of the KLF6 protein, as predicted by SOPMA. The remaining 7 regulatory SNPs significantly impacted the transcriptional activity of KLF6 following mutation (P < 0.005), manifesting as changes in transcription factor binding sites. Additionally, 4 SNPs located in both the UTR and exons were predicted to influence the secondary structure of KLF6 mRNA using the RNAfold web server. Furthermore, we performed the genotype-phenotype association analysis using SAS 9.2 which found all the 12 SNPs were significantly correlated to milk yield, fat yield, fat percentage, protein yield and protein percentage within both the first and second lactations (P < 0.0001 ~ 0.0441). Also, with Haploview 4.2 software, we found the 12 SNPs linked closely and formed a haplotype block, which was strongly associated with five milk traits (P < 0.0001 ~ 0.0203).ConclusionsIn summary, our study represented the KLF6 gene has significant impacts on milk yield and composition traits in dairy cattle. Among the identified SNPs, 7 were implicated in modulating milk traits by impacting transcriptional activity, 4 by altering mRNA secondary structure, and 1 by affecting the protein secondary structure of KLF6. These findings provided valuable molecular insights for genomic selection program of dairy cattle.

Milk-y Way: the impact of single-nucleotide polymorphisms on milk production traits in Kilis dairy goats.

This study aimed to investigate the impact of single-nucleotide polymorphisms (SNPs) on milk production traits in Kilis dairy goats by analyzing the genotypes of POU1F1, PRLR, -Lg, GH1, and GH2 genes and their association with lactation milk yield (LMY), lactation length (LL) and average daily milk yield (ADMY). Blood samples were collected from 227 goats, and genotyping was performed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). The results revealed that the frequencies of the genotypes varied among the genes. The polymorphisms were found to be significantly linked with milk production traits. These findings suggest that SNPs of POU1F1/AluI, PRLR/RsaI and -Lg/SacII are significantly associated with LMY and that the POU1F1-TC genotype, PRLR-TT genotype and -Lg-AB genotype are associated with higher LMY and ADMY. Additionally, the POU1F1-TC genotype was found to have a longer LL. However, no significant association was found between the GH1 and GH2 genotypes and LMY, LL and ADMY. Overall, this study provides valuable insights into the genetic factors influencing milk production traits in Kilis dairy goats, which can be utilized for the selection of high-yielding animals in breeding programs.

Factors and their influence on the indicators of milk productivity of first-born of Ukrainian dairy breeds

The article examines the influence of genotypic factors on the formation of milk productivity indicators in first-born cows of various breeds. Genotyping of 744 cows of Ukrainian Brown Dairy, Ukrainian RedAnd White, Ukrainian Black-and-White Dairy breeds and Sumy inbred type of Ukrainian Black-and-White dairy breed, which are kept in breeding farms of State Enterprise "Experimental Farm of Institute of Agriculture of Northern East of NAAS" of Sumy district of Sumy Region and PRAE Ichnyanske and PRAE Khliborob of Chernihiv region. In order to determine the polymorphism of the beta-casein gene, genetic studies were carried out in the laboratory of Institute of Physiology named after Bogomolets of NAS with the help of molecular biological analysis of allele recognition by polymerase chain reaction (PCR) in real time. The study of milk productivity indicators was carried out with the help of generally accepted methods, using the electronic database of SUMS "Orsek". The influence of genotypic factors was determined based on the results of one-factor variance analysis. Between animals of different breeds, there is a significant difference in the influence of genotypic factors on indicators of milk productivity. Linear belonging had a statistically significant effect on milk yield and the content of fat and protein in milk in animals of the Ukrainian black-and-white and redand-white dairy breeds. Whereas in cows of Ukrainian brown dairy breed - only on the amount of milk yield. In first-borns of Sumy intrabreed type, linear belonging did not have a statistically significant effect on the studied indicators. Father's origin has a much greater influence (ή2,=22-62 %). The genotype of the animal according to beta-casein actually does not have a reliable effect on the indicators of milk productivity. However, in animals of Ukrainian red-and-white dairy breed and Sumy inbred type of Ukrainian black-and-white dairy breed, it reliably influenced the formation of milk yield and fat content in milk. Therefore, with the aim of forming the desired value of milk productivity traits in first-born cows, the primary task is to carry out the selection of breeders assessed for the quality of the offspring of the corresponding lineal affiliation. Key words: genotype, beta-casein, influence, milk productivity, breed