Traits Of Cows Research Articles

Feeding Calcium Salts of Linseed Oil on Metabolic Status and Reproductive Traits in Grazing Dairy Cows

Feeding Calcium Salts of Linseed Oil on Metabolic Status and Reproductive Traits in Grazing Dairy Cows

Effect of dietary Chinese herbal preparation on dry matter intake, milk yield and milk composition, serum biochemistry, hematological profile, and reproductive efficiency of Holstein dairy cows in early postpartum period.

The present study investigated the effects of various inclusion levels of dietary Chinese herbal medicine (CHM) preparation on feed consumption, milk yield and milk composition, serum biochemistry, hematological profile, and reproductive efficiency of Holstein dairy cows. A total of 117 lactating Holstein cows were randomly divided into four groups as control (n = 27; without CHM supplementation) and treatment groups CHM-0.5 (n = 31), CHM-0.75 (n = 29), and CHM-1 (n = 30) fed diet supplemented with 0.5, 0.75, and 1 kg/cow/d for 30 days, respectively. The study began at d 20 postpartum (d 0 of the study). At d 50 postpartum, the cows in all groups were subjected to estrus synchronization using a modified Ovsynch protocol (GPGMH) and observed for reproductive variables. Feed intake, milk yield and milk composition, serum biochemistry and hematological profile, and reproductive efficiency were measured. A significantly higher milk yield with improved milk lactose, milk protein and milk fat were found in the CHM-0.75 group compared to the other groups (p < 0.05). Besides, the estrus response, ovulation rate, ovulatory follicle diameter, and pregnancy rate increased in CHM-0.75 compared to CHM-0 or CHM-0.5 group (p < 0.05). The serum metabolites (glucose, AST, arginine, BUN, and NO) showed variations among the treatment groups at different time points (synchronization, AI, or post-AI). In conclusion, CHM supplementation improves the milk yield, milk composition, and serum metabolites in dairy cows. Daily supplementation of 0.75 kg CHM before the GPGMH protocol application enhances the reproductive traits in dairy cows under summer conditions.

The effects of different feeding strategies providing different levels of vitamin A on animal performance, carcass traits, and the conversion rate of subcutaneous fat color in cull-cows

Abstract Cull cows represent a significant percentage of revenue received from the U.S. beef industry; however, cull cows are heavily price discounted at time of slaughter. This experiment’s objective is to evaluate different feeding strategies and their effects on body condition score, subcutaneous fat color, and carcass yield and quality traits in cull cows. The central hypothesis is feeding a high-energy diet, with low levels of vitamin A, for 56 d will improve animal performance, carcass yield, and quality traits in addition to capturing the point (rate) of the conversion of yellow to white subcutaneous fat. In the present experiment 98 Angus crossbreed cows were utilized. Cows were fed either low vitamin A (LVA) diet consisting of whole shelled corn, soybean hulls, soybean meal, and a mineral-vitamin supplement or high vitamin A (HVA) diet, formulated using whole shelled corn, fescue hay, dry distiller grains with soluble, and a mineral-vitamin supplement for 56 d. During the 56 d feeding period, body weights and condition scores, and subcutaneous adipose samples were collected every 14 d. On day 56, cattle were slaughtered; 48 h postmortem carcass characteristics and objective color scores (subcutaneous adipose tissue) were recorded and a sample of the longissimus dorsi lumborum was collected. Subcutaneous adipose tissue samples were utilized to record subjective color scores and then ground to be analyzed for β-carotene concentration. The longissimus dorsi lumborum samples (2.54 cm slices) were removed for Warner-Bratzler shear force (WBSF) and pH testing. Data were analyzed using the MIXED procedure of SAS. Feeding cull cows LVA resulted in differences in subcutaneous carcass fat color (P = 0.01) as well as b* values (P &amp;lt; 0.01) on day 56 compared with HVA. Subjective fat color scores were not different (P &amp;gt; 0.10) on day 0 or 14 but were different (P ≤ 0.05) on days 28, 42, and 56. Additionally, 9-cis-β-carotene concentration on day 56 were different (P = 0.05) between treatments. A trend was noticed for all-trans-β-carotene concentration (P = 0.10) on day 56 as well. Cull cow body weights were greater (P ≤ 0.04) when fed the LVA diet starting on days 14, 28, and 42; and a trend was noticed on day 56 (P = 0.09). Overall, cows fed the LVA treatment for 56 d exhibited decreased adipose yellowness and β-carotene concentrations as well as increased live weights.

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

Effect of GnRH treatment as a potential solution for ovarian disorders in dairy cows infected with foot and mouth disease in Indonesian smallholder farms.

The outbreak of foot and mouth disease (FMD) in Indonesia induces reproductive disorders in dairy cows that lead to economic losses to smallholder dairy farms. The study was to assess the influence of FMD on reproductive traits and evaluate the effect of gonadotropin hormone-releasing hormone (GnRH) administrations on the reproductive performance in FMD-infected dairy cows. The study was conducted in Jemowo village, Taman Sari sub-district, Boyolali district, Central Java, Indonesia. A total of 155 cows were used to identify the reproductive disorders on FMD-infected dairy cows aged 2-10 years old. Cows were raised in similar conditions and fed diets. A single dose of 2 ml GnRH was injected intramuscularly into 96 ovarian disorder cows. Reproductive performance was measured by service per conception (S/C), conception rate (CR), and pregnancy rate (PR). A descriptive study was conducted to demonstrate the results. The study showed that 61.9% of FMD-infected cows had reproductive disorders, whereby 53.5% ovarian hypofunction, 4.52% silent heat, 1.94% repeat breeder, 1.29% ovarian atrophy, and 0.65% endometritis. FMD-infected cows injected with GnRH had a 98% reproductive recovery rate. Moreover, the S/C, CR, and PR of cows injected with GnRH were 2.02%, 51%, and 85%. GnRH administrations enhanced the reproductive traits of FMD-infected dairy cows indicated by the improvement of CR and PR.

Reproductive and productive traits of cows of Holstein breed depending on the level of inbreeding

Inbreeding is one of the main criteria in programs for the conservation and use of genetic resources, and it can be used to control genetic processes in populations of farm animals. The use of inbreeding involves the production and consolidation of rare genotypes, which determine the outstanding quality of animals. The purpose of the work was to determine the reproductive and productive traits of cows of Holstein breed depending on the level of inbreeding. The research was carried out in the pedigree farm in the Kaluga region. The research of the reproductive ability of first-calf heifers obtained through inbreeding and outbreeding were shown significant differences in the duration of the calving interval. So, cows obtained through the remote inbreeding had the lowest duration calving interval (385.4 days) and their herdmates from outbreding had the longest calving interval (404,5 days), the difference was 19.1 days (p&lt;0.05) or 5.0%. Cows from remote inbreeding had the shorter calving interval than their herdmates from moderate inbreeding by 15.9 days (p&lt;0.05) or 4.1%. It was found that higher milk yields for 305 days of the first lactation had cows obtained through remote inbreeding (6413.1 kg), and low milk yields of milk were obtained from first-calf heifers from moderate inbreeding (5634.8 kg), the difference was 778.3 kg (p&lt;0.05) or 9.0%. They also surpassed the milk yield of their herdmates obtained from outbreeding by 266.6 kg (p&lt;0.05) or 4.3%. First-calf heifers obtained through moderate inbreeding were inferior in milk yield to herdmates from outbreeding by 511.7 kg or 9.1% (p&lt;0.05).

Genetic Polymorphisms of SCD1 gene and its relationship with some reproductive traits in Holstein cows in Iraq

The research was conducted at the Khalis cows station in Al-Khalis district - Diyala Governorate and the central laboratory of the Faculty of Agriculture - University of Tikrit for the period from 13/12/2020 to 1/2/2022, a sample of 63 Holstein cows, with the aim of extracting the genetic material and determining the genetic polymorphism of the SCD1 gene and its relationship to reproductive traits in Holstein cows, studying the percentage of distribution of genetic structures in the cows that were studied, the allele frequency and calculating the value of chi-square (χ2) were determined. The genotypes frequencies for the SCD1 gene in the studied cow samples were 47.62, 46.03 and 6.35% for AA, AV and VV genotypes respectively. The value of the chi-square (χ2) was highly significant (P &lt; 0.01). The frequency of allele A and V were 0.71 and 0.29 respectively. Some reproductive traits were significantly affected by the different genotypes of the SCD1 gene. Cows with the genotype AA achieved the highest Days Open (106.70 ± 5.84 days), while the genotypes VV and AV were 105.93 ± 14.25 and 92.82 ± 5.89 days respectively. The cows with AA genotype was the highest calving interval (389.77 ± 5.90 days), while the cows of the VV and AV genotypes reached 386.75 ± 14.39 and 374.27 ± 5.96 days respectively. It can be concluded by studying the genetic polymorphism of the SCD1 gene that it is possible to improve the reproductive traits in cows. We also recommend applying the study to a larger sample for several seasons and different locations of the gene, while studying more economic characteristics to give more accurate results for the application of the selection and exclusion strategy.

Host and rumen microbiome contributions to feed efficiency traits in Holstein cows

It is now widely accepted that dairy cow performance is influenced by both the host genome and rumen microbiome composition. The contributions of the genome and the microbiome to the phenotypes of interest are quantified by heritability (h2) and microbiability (m2), respectively. However, if the genome and microbiome are included in the model, then the h2 reflects only the contribution of the direct genetic effects quantified as direct heritability (hd2), and the holobiont effect reflects the joint action of the genome and the microbiome, quantified as the holobiability (ho2). The objectives of this study were to estimate h2, hd2,m2, and ho2 for dry matter intake, milk energy, and residual feed intake; and to evaluate the predictive ability of different models, including genome, microbiome, and their interaction. Data consisted of feed efficiency records, SNP genotype data, and 16S rRNA rumen microbial abundances from 448 mid-lactation Holstein cows from 2 research farms. Three kernel models were fit to each trait: one with only the genomic effect (model G), one with the genomic and microbiome effects (model GM), and one with the genomic, microbiome, and interaction effects (model GMO). The model GMO, or holobiont model, showed the best goodness-of-fit. The hd2 estimates were always 10% to 15% lower than h2 estimates for all traits, suggesting a mediated genetic effect through the rumen microbiome, and m2 estimates were moderate for all traits, and up to 26% for milk energy. The ho2 was greater than the sum of hd2 and m2, suggesting that the genome-by-microbiome interaction had a sizable effect on feed efficiency. Kernel models fitting the rumen microbiome (i.e., models GM and GMO) showed larger predictive correlations and smaller prediction bias than the model G. These findings reveal a moderate contribution of the rumen microbiome to feed efficiency traits in lactating Holstein cows and strongly suggest that the rumen microbiome mediates part of the host genetic effect.

Estimates of Genetic and Phenotypic Parameters of Milkability Traits in Holstein Friesian and Simmental Cows

Bu çalışma da Kahramanmaraş ilinde yetiştirilen Siyah Alaca ve Simental sığırların süt akış hızı, sağım süresi ve süt verimine ilişkin fenotipik ve genetik parametre tahminleri elde edilmiştir. Araştırmada 150 baş Siyah Alaca ve 40 baş Simental ineğin süt verim kayıtları kullanılmıştır. Süt akış hızı, sağım süresi ve süt verimine ilişkin genel ortalamalar Siyah Alaca ırkında; 1.370.004 kg dak-1, 16.700.017 dak ve 21.320.026 kg, Simental ırkında ise 1.0470.007 kg dak-1, 17.740.034 dak ve 16.820.049 kg olarak hesaplanmıştır. Mevsim etkisi her iki ırkta da tüm özellikler için önemli (P0.0001) bulunmuştur. Sağım zamanı etkisi ise Siyah Alaca ırkında günlük süt verimi ve süt akış hızı, Simental ırkında ise günlük süt verimi ve sağım süresi için önemli (P0.0001) bulunmuştur. Süt akış hızı, sağım süresi ve süt verimine ilişkin kalıtım dereceleri Siyah Alaca ırkında; 0.110.015, 0.320.03 ve 0.130.02, Simental ırkında ise 1.0470.007 kg dak-1, 17.740.034 dak ve 16.820.049 kg olarak hesaplanmıştır. Her iki ırkta da sağım özellikleri arasındaki genetik korelasyonlar orta-yüksek bulunmuştur. Bu çalışmada ele alınan özelliklerin kalıtsal olduğu ve seleksiyonla geliştirilebileceği sonucuna varılmıştır.

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.

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

Heritability and correlative variability of the conformation linear traits of first-born cows of black-and-white cattle with milk yield

An in-depth analysis the publications of domestic and foreign authors was carried out in the aspect of research on the heritability of linear traits of the conformation type and their correlative variability with milk productivity.The research authors established that the level of existing variability in the heredity of linear traits depends on many genotypic and paratypic factors. However, they argue that despite the variability of traits heritability of dairy cows conformation, their level is generally sufficient for effective selection by linear type traits. Studies on the correlation between linear traits of type and milk productivity of cows of various breeds around the world have shown a high level of this relationship. This testifies about the effectiveness of indirect selection of dairy cattle by type, which will allow obtaining not only constitutionally strong and healthy animals, but also with high milk productivity.The population-genetic aspect of determining the heritability and correlative variability of linear traits with milking of first-born Holstein cows of domestic selection and Ukrainian Black-and-White dairy in the private enterprise "Burynske" of the Podlisniv branch of the Stepaniv territorial community in Sumy district was described. The magnitudes and reliability of the heritability coefficients of group linear traits indicate that they are controlled by the genotype of animals by 24.5-42.2 % in first-born cows of the Holstein breed, and by 26.6-40.1 % in female cows of Ukrainian Black-and-White dairy breed. The final score by type of 48.2 and 45.4 %, respectively, ensures the efficiency selection of cows by genotype. Variability of descriptive traits of Holstein cows ranges from insignificant and unreliable (h2=0.084; location of front teats) to high and reliable (h2=0.484; angularity). In females of the same age of Ukrainian Black-and-White dairy breed, the variability varies from 0.077 (location of rear teats) to 0.422 (angularity).In Holstein and Ukrainian Black-and-White dairy cows, the most reliable relationship was found between the characteristics of the dairy type (0.428 and 0.387), body (0.446 and 0.439), udder (0.486 and 0.478) and, especially, the final type score (0.492 and 0.488), which gives reason to assert about the effectiveness of selection based on these traits.The highest level of reliable positive correlation with the amount of milk yield for the first lactation was found according to the scores of descriptive traits of Holstein and Ukrainian Black-and-White dairy breeds, respectively: height (r=0.363 and 0.322), body depth (r=0.468 and 0.484), angularity (r=0.477 and 0.466), back width (r=0.366 and 0.322), posture of pelvic limbs (r=0.369 and 374), attachment of front (r=0.482 and 0.426) and rear (r=0.371 and 0.351) udder parts, central ligament (r=0.364 and 0.375) and locomotion (r=0.363 and 0.322) at Р&lt;0.001. Key words: Holstein, UkrainianBlack-and-Whitedairy, lineartypeevaluation, conformation, milkyield, first-borncows.

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

The effect of the silvopastoral system on milk production and reproductive performance of dairy cows and its contribution to adaptation to a changing climate in the drylands of Benin (West-Africa)

Knowledge about dairy cows raised in small-scale agroforestry systems in dryland areas is of paramount importance to inform policy and decision making in the dairy production sector in the current context of climate change. The aim of this study was to evaluate the effect of integrated farming systems on daily milk yield and demographic traits of dairy cows in drylands. A study conducted on 447 dairy cows was carried out to compare their milk yield and demographic parameters under different small-scale agroforestry systems in drylands of Benin: traditional silvopasture (TSS); Improved silvopasture (ISS); Small Integrated Agrosilvopasture (SIAS) and Large Integrated Agrosilvopasture (LIAS). The type of cattle farms had a significant effect (p &amp;lt; 0.05) on daily milk yield and demographic traits. Dairy cattle from ISS farms had the highest daily milk yield regardless of the type of dairy cow breed. Demographic traits of herds were significantly (p &amp;lt; 0.05) influenced by the type of dairy cattle farms. The proportion of lactating cows was higher (p &amp;lt; 0.05) in herds of ISS (48.4%) followed by those in TSS and LIAS (36.1 and 25.0% respectively) while SIAS was the lowest in (14.4%). The pre-weaning mortality rate was higher (p &amp;lt; 0.05) in TSS and LIAS farms (18.3 and 17.6 % respectively) compared to SIAS and ISS farms (5.20 and 4.60 % respectively). The fertility rate was higher (p &amp;lt; 0.05) in ISS and SIAS farms (92.3 and 89.6% respectively) compared to TSS and LIAS farms (68.3 and 74.2% respectively). The weaning productivity was higher (p &amp;lt; 0.05) in ISS and SIAS (88.6 and 85.8 % respectively) than in TSS and LIAS farms (66.1 and 67.6 % respectively). This study showed that ISS farms are characterized by higher milk yield and demographic parameters. ISS systems can then be promoted in smallholder cattle farming to improve milk production and reproductive performance of dairy cows in drylands.

Polymorphism of ADAM12, DPP6 and PRKN genes and their associations with milk production traits in Holstein.

Milk production traits as the most important economic traits of dairy cows, they directly reflect the benefits of breeding and the economic benefits of pasture. In this study, A disintegrin and metalloproteinase-12 (ADAM12), Parkinson's disease gene 2 (PRKN) and dipeptidyl peptidase-like protein subtype 6 (DPP6) polymorphism in 384 Chinese Holstein cows were detected by time-of-flight mass spectrometry and through statistical analysis using software such as Popgene 32, SAS 9.4 and Origin 2022, the relationship between single nucleotide polymorphisms (SNPs) of three genes with four milk production traits such as daily milk yield (DMY), milk fat percentage (MFP), milk protein percentage (MPP) and somatic cell score (SCS) was verified at molecular level. The results showed that four polymorphic loci (116,467,133, 116,604,487, 116,618,268 and 116,835,111) of DPP6 gene, two polymorphic loci (97,665,052 and 97,159,837) of PRKN gene and two polymorphic loci (45,542,714 and 45,553,888) of ADAM12 gene were detected. PRKN-97665052, DPP6-116467133, ADAM12-45553888, DPP6-116604487 and DPP6-116835111 were all in Hardy-Weinberg equilibrium state (p > .05). ADAM12-45542714, PRKN-97159837 and PRKN-97665052 were moderately polymorphic (0.25 ≤ PIC <0.50) in Holstein. It is evident that the selection potential and genetic variation of these five loci are relatively large, and the genetic richness is relatively high. The correlation analysis of different genotypes between these eight loci and milk production traits of Holstein showed that ADAM12-45542714 and DPP6-116835111 (p < .01) had an extremely significant effects on the DMY of Chinese Holstein in Ningxia, while PRKN-97665052 had an extremely significant effect on MFP (p < .01). The effect of PRKN-97665052 and DPP6-116467133 on MPP of Holstein were extremely significant (p < .01). DPP6-116618268 had an extremely significant effect on the SCS of Holstein in Ningxia (p < .01), and AA genotype individuals showed a higher SCS than GG genotype individuals; the other two loci (ADAM12-45553888 and DPP6-116604487) had no significant effects on milk production traits of Holstein (p > .05). In addition, through the joint analysis of DPP6, PRKN and ADAM12 gene loci, it was found that the interaction effect between the three gene loci could significantly affect the DMY, SCS (p < .01) and MPP (p < .05). In conclusion, several different loci of DPP6, PRKN and ADAM12 genes can affect the milk production traits of Holstein to different degrees. PRKN, DPP6 and ADAM12 genes can be used as potential candidate genes for milk production traits of Holstein for marker-assisted selection, providing theoretical basis for breeding of Holstein.

LIFESPAN OF DAIRY CATTLE DEPENDING ON THE LEVEL OF EVALUATION OF UDDER LINEAR TRAITS

The dependence of cows lifespan of Ukrainian Black-and-White dairy (UBWD) and Holstein (H) breeds on the level of evaluation of linear type traits that characterize udder morphological qualities in the general system of linear classification was studied. Descriptive traits of the evaluated conformation type were: front udder parts attachment, height of rear udder parts attachment, central ligament, udder depth, front teats placement and length. A certain correlative variability was established between level of evaluation of linear type traits and lifespan of animals. The highly reliable difference between evaluated cows for linear type trait of front udder parts attachment with 1 and 9 scores is significant and was 841 (UBWD; P&lt;0.001) and 810 (H; P&lt;0.001) days. An interbreed comparison of cows lifespan, depending on the evaluation, testified in favor cows of Holstein breed with variability within 43-159 days by an unreliable difference. Difference between the lowest and highest scores for type trait of height rear udder attachment in cows of experimental breeds was 740 (UBWD; Р&lt;0.001) and 810 (H; Р&lt;0.001) days. Animals with an assessment for trait development of central udder ligament lower than 1-3 scores live, according to evaluated breeds, from 2089 to 2401 (UBWD) and from 2154 to 2468 (H) days. Cows with 9 scores for both breeds had the highest lifespan – 2663 days (UBWD), inferior to cows with the lowest score by 754 (Р&lt;0.001) and 2803 days (H) with significant increase on 649 days (Р&lt;0.001). Difference between the average lifespan in cows of Ukrainian Black-and-White dairy breed with 9 and 1 scores for linear type trait of udder depth was 739 (Р&lt;0.001) and 832 days (Р&lt;0.001) in Holstein cows. Lifespan of cows both breeds in the herd was characterized by slight curvilinear variability, depending on the assessment of linear type trait of front teats placement. Consequently, cows of both breeds with an average score of 7 were used in the herd for the longest period. Evaluation of correlative variability of the front teats length with lifespan of cows in controlled breeds indicated that animals with an average score of 5, which was equal to their teats length at 5 cm, had longer functional life. Research results showed that each of evaluated descriptive traits in cows of both breeds has an impact on lifespan with different variability within individual body part, so better expression of linear type trait can be a breeding trait as an indirect predictor of longevity.

Correlations of reproduction and productive traits in Holstein cows during dynamics on lactations

The task facing livestock breeders is to get a calf from each cow during the calendar year. Insemination of cows in the fi rst two months after calving is a necessary condition for increasing the rate of reproduction of livestock on the farm and increasing the economic effi ciency of the dairy industry. The purpose of the work was to evaluate the correlations between reproduction and productive traits in dairy cattle of Holstein breed, taking into account age in lactations. It was established as a result of the research that the herd has a large number of young cows in their fi rst and second lactations. The highest productivity indicators were found in cows in the third lactation, then there was a decrease in milk yield until the end of their use with slight fl uctuations in the direction of increase or decrease in milk yield, but in any case they turned out to be lower than in the third lactation. The mass fraction of fat in milk is a fairly stable indicator, as is the mass fraction of protein. The duration of the period of open days generally exceeded the optimal norms by 13–24 days or 14,4–26,7 %. This leads to the increase in the duration of lactation and the calving interval. The reproductive effi ciency coeffi cient ranged from 0,97 (9 and 10 lactations) to 0,91 (1, 5 and 11 lactations) and was mostly below 0,95, but tended towards this indicator. It can be concluded that the breeding stock in the dairy cattle herd of the breeding farm has satisfactory reproductive traits and there are certain problems with reproduction. The reliable influence of the duration of the period of open days on the milk productivity of cows has not been determined. Based on milk yield during early lactation we can predict about the further productivity of cows.

Estimation the genetic parameters and evaluating the correlation between the maternal linear type traits and the birth weight of the progeny in Hanwoo cows

This study aimed to investigate the correlation between the linear type traits of mother cows (dams) and the birth weight(BW) of the progeny. The study used data collected between 2002 and 2018 by the Korea Animal Improvement Association (KAIA). This study evaluated the data specifically with respect to 19 traits. A statistical model was established to estimate the correlation between the maternal linear classification traits and the progeny BW. The significance of each statistical variable was analyzed using the generalized linear model (GLM) method in the SAS package 9.1.3 software, while the genetic parameters were estimated using the BLUPF90 Family program. The BW of Hanwoo cows increased by approximately 0.4 kg each year; however, the BW heritability was moderate (0.23). The linear classification traits showed values of 0.34, 0.37, 0.11, 0.45, 0.31, and 0.40, for ST (Vertical distance from the apex of the rump to the ground), BL (Horizontal distance between anterior shoulder point to the posterior extremity of the pin bone), RA (The slope from the rump to the pin bone), RL (Horizontal distance from the anterior rump to the tip of the pin bone), PBW (Lateral width of pin bone), and FS (Final score), respectively, with moderate heritability for all traits, except RA. The BW of the progeny showed phenotypic correlations of 0.06, -0.01, 0.03, and 0.04, and genetic correlations of 0.09, 0.03, 0.02, and -0.04 with ST, BL, RL, and PBW, respectively. The average parity in Hanwoo cows increased from 2.5 in 2016 to 2.8 in June 2020. There is a low genetic correlation between the maternal linear classification traits and the BW of the progeny. An increase in the parity of dams and a greater accumulation of progeny BW data and test records could lead to the accurate evaluation of the BW as a breeding objective trait.

Assessing and explaining trends in dairy cattle herd performance variables while using three-breed rotational crossbreeding: empirical evidence from commercial farms

Three-breed rotational crossbreeding can improve the functional traits of dairy cows, but few farmers in most Western countries use it. This could be due to a lack of knowledge of its medium- and long-term effects on animal performance at the herd level, regardless of the initial states of the farm and herd, the crossbreeding programme(s) used and changes in farm management and structure while transitioning to it. We aimed at assessing changes in animal performance of dairy cattle herds transitioning towards three-breed rotational crossbreeding and at identifying factors that explained them. We sampled 13 French dairy cattle farms for which animal performance data were available for a 9-year period (2009–2017) and described their trends in herd management and the farming system when introducing crossbreeding. We calculated five herd performance variables: mean milk productivity per cow-year (MilkCow), mean Milk solids content (FatProtCont), and the percentages in the herd of cows with no more than 117 days open (FertileCow), with mean somatic cell score less than 4 over the lactation period (HealthyLact) and with four lactations or more (L4+). We defined 15 variables related to herd and farm structure and management. We applied linear regression to each variable over the study period and used the intercept and slope to describe their initial values in 2009 and their trends, respectively. We performed partial least squares (PLS) regression to assess relationships between the trends in herd performance variables and potential explanatory variables, including the initial values of herd performance variables and the initial values of and trends in herd and farm structure and management variables. Linear regressions showed that within herds, median MilkCow decreased (–177 kg/cow per year), FertileCow increased (+1.5%/year) and FatProtCont either remained stable or increased (+0.1 g/kg per cow). Conversely, changes were less distinct for HealthyLact and L4+. From 2009 to 2017, herd size increased in most farms (med = +1.2 LU/year). The PLS regression highlighted that herds in which MilkCow decreased the most over time were those in which HealthyLact and L4+ decreased and increased the most, respectively. Moreover, for herds in which FertileCow increased the most, FatProtCont either decreased, or increased less. Based on association scores from the PLS, changes in the genetic composition of the herd influenced changes in herd performance variables more than did changes in overall farm management (|0.28|–|0.59| vs |0.26|–|0.50|). Our findings suggest that dairy crossbreeding is relevant to rebalance herd performance between production and functional traits.

Genetic parameters for lifetime productivity in Holstein and Brown Swiss dairy cows in Honduras

Objective. To estimate the heritability (h2) of age at first parturition (AFP), longevity (L), useful life (UL), and productivity (P), as well as the genetic (rg) and phenotypic correlations between those traits in Brown Swiss and Holstein cows in Northwestern Honduras. Materials and methods. Cattle were raised under tropical conditions and intensive management. The model for AFP assessed the effect of contemporary group (herd, year and birth season combination) as fixed. The model used for L, UL and P included the contemporary group, age group at first calving and their interaction. Data were analyzed using restricted maximum likelihood procedure, adjusted to a univariate and to a bivariate animal model. Results. The h2 estimated for AFP, L, UL and P were 0.16, 0.18, 0.25 and 0.09, respectively, in Brown Swiss cows, and 0.53, 0.49, 0.7 and 0.22, respectively in Holstein. Negative but favorable rg among Brown Swiss cow traits ranged from 0.31 to 0.46 between AFP and the other traits. However, for Holsteins cows, positive rg among AFP and the other traits here studied varied from 0.49 to 0.96. In both cattle breeds, rg among L, UL and P, traits were positive. Conclusions. For all traits evaluated low to medium heritability’s for BS suggest that a slow genetic improvement could be achieved if independent selection of traits is applied, and better response could be expected for H breed. For both breeds the positive rg among L, UL and P suggest thar similar selection criteria could be used.