„dairy cows“ 37 výsledků

The polymorphism of the kappa-casein gene (CSN3) has been studied in cows of the Lebedyn, Simmental, Ukrainian Black-and-White dairy breeds using a real-time polymerase chain reaction. The TaqMan® SNP Genotyping Assays use TaqMan® 5´-nuclease chemistry for amplifying and detecting specific polymorphisms in purified genomic DNA samples. All assays are developed using Life Technologies robust bioinformatics assay design process relying on a pipeline using heuristic rules deduced from both manufacturing and assay performance data. The objective of our study is to evaluate the cattle of Ukrainian domestic dairy breeds according to the kappa-casein genotype. It has been shown that the distribution of genotype frequency differs significantly in different breeds: Lebedyn – 19% A/A, 50% A/B and 31% B/B; Ukrainian Brown dairy – 30% А/А, 41% A/B and 30% B/B; Simmental – 44% A/A, 46% A/B and 10% B/B; Ukrainian Black-and-White dairy – 58% A/A, 27% A/B and 15% B/B. The results obtained indicate the prospects of breeding work towards creating herds with the BB genotype in the Brown cattle. The accelerated formation of the desired genetic combinations in micropopulations (herds), with the needs of the processing industry, primarily cheesemakers, is possible in the population of the Brown and Lebedyn breed. Such work with dairy herds of the Ukrainian Black-and-White and Simmental breeds requires more time for selection due to the low frequency of BB genotypes in cattle of these breeds.

Currently, the prices of dairy cows feed with protein concentrates are rising and the climate change is also manifesting itself with a growing drought in animal production. These are the reasons why there is an increasing interest in growing silage from legume–cereal mixtures (L-C-M) and in increasing their share in feed rations for dairy cows. Furthermore, the L-C-Ms improve the soil fertility during the crop rotation. The effect of these feeds on milk quality was evaluated by adding L-C-M silages into feeding rations. Czech Fleckvieh and Holstein breed dairy cows (8 herds; feeding periods without and with L-C-M silages) were included in the evaluation for 3 years. There were used 126 L-C-M (experimental) and 463 control (without L-C-M) bulk tank milk samples in this dairy analysis. Lactose content, solids non fat content and total count of mesophilic bacteria in milk of L-C-M group was increased as compared to control (zero hypothesis probability varied from P ≤ 0.05 to P ≤ 0.001). On the contrary, as new knowledge, milk freezing point depression and somatic cell counts were decreased in L-C-M group as compared to control (P ≤ 0.001 and P ≤ 0.05). Other milk indicators such as contents of fat, crude protein, milk urea and thermostability (P > 0.05) were not affected by evaluated factor. The residues of inhibitory substances in bulk tank milk in the L-C-M group were not indicated, but one case was in the control group. Feeding of dairy cows with an increased proportion of L-C-M silage in the roughage component a part of the feeding ration is a safe way to replace part of the protein concentrates in animal feeding, regarding milk quality.

The aim of the study is to evaluate the relation of protein nutrition to transformation of nitrogen (N) from feed to milk and its urinary excretion in dairy cows under the farm conditions. In breeding conditions of dairy farms in the groups of dairy cows in the 1st phase of lactation, with low content of CP (139±11.8 g/kg), optimum (161.8±6.3 g/kg) and high content of CP (179.7±8.5 g/kg) in dry matter of total mix ration (TMR), was confirmed the effect of increased the level of ammonia (NH3) in the rumen (17.4±1.7; 19.6±2.3; 22.8±3.4 mg/100 ml). The same tendency with higher statistical significance (P<0.001) was confirmed to the increased concentration of urea in the blood (22.8±3.7; 27.8±4.8; 35.1±6.6 mg/dl) and to the concentration of urea in the milk (18.2±2.6; 24.8±3.9; 33.3±6.7mg/dl). In the groups with increasing content of CP in the TMR, the ecological load of the environment increases, that was confirmed by a significant increase (P<0.001) of excreted N in the urine (139.4±19.8; 189.5±30.4; 254.7± 51.3 g N/day) and an increase (P<0.001) in the emission of ammonia into the environment (68.1 ± 6.1; 83.7 ± 9.4; 103.8 ± 15.9 g/day). The highest efficiency of N utilization at the level of 31.1 ± 1.4 % was confirmed at a CP content of 150-170 g/kg dry matter of TMR. The evaluation of direct regression dependence between the analysed CP content in TMR and analysed parameters of N transformation in individual farms was confirmed a significant relationship in CP and NH3 content (r = 0.641), CP and urea in the blood (r = 0.689) resp. CP and excretion of N in urine (r = 0.600). Direct relation was confirmed by the analysed NH3 content in the rumen and the urea content in the blood (r = 0.795), and urea in the milk (r = 0.786), as well as the urea content in the blood in relation to the urea in the milk (r = 0.767). The obtained results confirm the suitability of the use of the monitored markers to assess the level of protein nutrition and the environmental load at the farm.

The growth intensity of cattle significantly affects their future production and reproduction performance. Despite this fact, many breeders underestimate the rearing of calves and heifers. Our study aimed to evaluate the growth intensity of Holstein calves and heifers in PD Devio Nové Sady based on non-contact measurement of live weight and body measurements through the analysis of digital images using the app AGRONINJA beefie3dTM. The growth intensity analysis was based on the standard Penn State protocol, which uses the Hoffman method to estimate growth standards. A total of 143 calves and heifers were evaluated in three independent measurements. Obtained data were compared to an optimal growth curve determined based on the weight and wither height of dairy cows on the third lactation and using a system of growth intensity requirements. The results showed several deficiencies in the growth intensity of animals on the selected farm. We observed a growth deficit in the height of the evaluated calves from 3 to approximately 4.5 months of age. In addition, we observed that heifers older than eight months exceeded the set weight optimum. We also found a significant decrease in growth intensity due to the disease which occurred in the herd. The results of this study showed that regular recording of data related to body measurements and weight, as well as their comparison with the required values, makes it possible to reveal and, at the same time, eliminate many deficiencies in the breeding of heifers that will form the future production herd.

The pilot survey among 36 Simmental cattle breeders in Slovakia was performed by an expert visiting farms and filling a questionnaire with farm managers. Data on the factors that influence the emission factors of ammonia, methane or nitrous oxide are needed to provide support for sustainable livestock production policies. Highest milk production (8305±828 kg) was found in the group with intensive production system comprising 7078 cows. Extensive systems were represented by only 2 farms with 451 cows producing 5527±1094 kg of milk. All farms used phase feeding, only 15% of all cows in the survey were grazing. The dominant way of handling animal waste was solid manure with straw bedding (30 farms), while slurry prevailed for the remaining farms. There were 8 farms (2095 cows) equipped with surface covered tanks, bags or using natural crust to reduce emission from slurry storage. Median emission factors of a dairy cow based on survey data were 137.21 kg, 0.850 kg and 50.79 kg per year for methane, nitrous oxide and ammonia, respectively. When aggregated by manure management, cows producing solid manure had a lower emission factor for methane but higher for ammonia and nitrous oxide compared to cows under liquid manure management. Linking data from various aspects of dairy production at farm level supports holistic approach as important for evaluation of food systems in the future.

In this case study, the urinary mineral profile of dairy cows was investigated. Determined urinary mineral concentrations were evaluated in relation to the production cycle (dry cows versus lactating cows) and were also compared to the physiological optimum. The study was carried out on twelve Holstein-Friesian dairy cows. Calcium, phosphorus, magnesium, sodium and urea concentrations were determined in urine samples. The urine of dry cows showed demonstrably higher concentrations of Ca, P, Na and Mg compared to the urine of lactating cows. Compared to the physiological optimum, significantly lower urinary Na concentrations were determined in all cows. This indicates a significant deficiency of Na in the diet of both dry cows and lactating cows. Marked differences between the minimum and maximum concentrations of all minerals studied in the urine of dairy cows were determined. The mineral profile obtained from urine samples can be an important diagnostic method for detecting preclinical stages of metabolic disorders. At the same time, urine sample collection is stress-free for dairy cows.

The research of polymorphism of the PIT-1 and beta-lactoglobulin genes has been provided on the population of Ukrainian brown dairy and Sumy intrabreed type Ukrainian black-and-white dairy cows. The study of genotypes has been carried out using polymerase chain reaction in real time. The existence of interbreed differentiation in the frequencies of genotypes and alleles of the studied genes has been proved. The influence of the studied genes genotype on individual indicators of milk productivity of cows has been established.

The study aimed to examine the analyses of the trend in the numbers of dairy cows, production and reproductive traits in the population the Slovak Spotted cattle for period 2010 to 2019. The number of Slovak Spotted dairy cows is maintained on a relatively stable level in recent years. There was a decrease in the number of animals (12 428 in 2010), but not as strong as after 1990 (85 518). From 2017 number of animals is rising from 14,062, to 14,150 (2018) and 14,627 (2019), respectively. As compared to 2010 an increase of 13.15% in 2017, 13.86% and 17.68%, in 2018 and 2019 respectively was observed. Population size raised from 113.15% (2017) to 117.68% in 2019 respectively. The average annual increase in milk production between the years 2010 to 2019 was + 157.5 kg of milk (total 1,575 kg of milk), + 5.8 kg of fat (total 58 kg of fat) and + 6.1 kg of protein (total 61 kg of protein). Positive growth of milk production in recent years is slightly comparable with the trend of breeding improvement.

Feed efficiency has a major influence on farm profitability and environmental stewardship in the dairy industry. The aim of this study was to describe a new selection index adopted by the Italian Holstein and Jersey Association (ANAFIJ, Cremona, Italy) to improve feed efficiency using data recorded by the official dairy recording system. Predicted dry matter intake (pDMI) was derived from milk yield, fat content, and estimated cow body weight. Fat-protein corrected milk (FPCM) was derived from milk yield corrected for fat, protein, and a fixed coefficient for lactose content (4.80%). Therefore, the predicted feed efficiency (pFE) was estimated as ratio between FPCM and pDMI. Average pFE was 1.27±0.18 (kg.d-1) with heritability of 0.32. Predicted Feed Efficiency index (pFEi), traditional and genomic, has been implemented in the Italian Holstein Friesian evaluation system. Results suggest that pFEi may be a new breeding objective for Italian Friesians. The official selection index (PFT), in use since 2002, is positively correlated with pFEi. However, the introduction of pFEi will improve the positive feed efficiency trend. This approach will permit the Italian Holstein Friesian breeders to improve feed efficiency, without increasing costs of recording system. However, to avoid the risk of selecting animals with an excessive negative energy balance after calving, it would be useful to include in the pFE a correction for body condition score and reproductive performances. Meanwhile, in order to increase the accuracy of the predicted phenotype, an Italian consortium is creating a consistent phenotypic critical mass of individual data for dry matter intake in cows, heifers and young bulls.

The aim of the study was to evaluate the effect of birth season, average maximum temperatures 6 weeks before and after birth of heifers on their first lactation milk yield. In chosen herd, the effect of birth weight, weight gain until weaning on first lactation milk yield was also investigated. Additionally, the effect of the average maximum temperatures before birth, effect of birth season on birth weight were evaluated. The data were collected from the herd “A” in Orava region consisting of Slovak spotted breed (127 records), the herd “B” in Lower Nitra (150 records) and herd “C” in Upper Nitra (116 records) both consisting of black Holstein Friesian cows. Birth season tended to influence the heifers first lactation milk yield in the herd “C” (P <0.06). The maximum average temperatures during the first 6 weeks after birth significantly affected heifers first lactation in the herd “A” (P <0.01). The maximum average temperatures affecting pregnant cows before birth of their heifers did not influence heifers’ milk yield during the first lactation in all herds (P >0.66, herd “A”; P >0.59, herd “B”; P >0.38, herd “C”). In the herd “B” there was insignificant effect of prenatal temperatures, birth season on birth weight of heifers (P >0.97; P >0.74). However, the heifers with the highest weight gains until weaning had numerically higher first lactation milk yield (P >0.20).

DGAT1 gene polymorphism in exon 8 AA→GC which converts lysine to alanine at position 232 (K232A) was determined to have significant influence on bovine milk production characteristics like milk yield, protein content, fat content, and fatty acid composition. The aim of this study was to analyse the effect of DGAT1 gene polymorphism on dairy production traits [milk yield (kg), fat yield (kg), fat content (%), protein yield (kg) and protein content (%)]. Genotyping of 136 Holstein cows was performed using the ACRS-PCR method. The genotypes frequencies were as follows: homozygous genotype AA (80.88%), heterozygous genotype AK (16.91%) and homozygous genotype KK (2.21%). In the monitored population, allele A had a predominance with a frequency of 89.34% over allele K with a frequency of 10.66%. In the study was observed a statistically significant (P <0.0001) effect of DGAT1 K232A marker genotypes on breeding value variability for milk fat and protein content (%) as well as milk yield (kg) was observed.

The aim of this research was to evaluate the effect of cow exterior on the weight of the calf at parturition and the size of the calf’s head. 453 purebred Holstein Friesian dairy cows at a selected farm were analysed within this research, and the measurements of the withers height, hip width, backside width and ischial width were taken from each specimen. Considering the calves, the measurements taken were the width and length of the head and weight at parturition. The research did not prove any significant (p>0.05) effect of the cow body conformation on any of the measured proportions of the calf. There was, however, a significant (p<0.05) difference in the head length and weight in calves in relation to the calving ease. As opposed to our expectations, the parturition weight of calves going through a more difficult parturition was lower (30.36 kg, as opposed to 36.57 kg in the less difficult parturition) and the length of the head was lower as well (23.47cm, as opposed to 23.98 cm in a less difficult parturition). At the same time, the weight and head length increased with each undergone lactation cycle of the mother – more specifically, this trend of increasing was observed from the first to the fifth lactation cycle. The parturition weight of calves was significantly affected by the gestation length itself. Another factors that had an effect on the weight and size of the calves were the season during which calving took place and the effect of the father bull. The results show a possibility of using the data collected in this research for breeding value estimation in difficult parturitions, since the effect of the father of the calf has to be taken into consideration as well as the effect of the the cow’s father.

The study is focused on the evaluation of the changes in locomotion activity and rumination time in heifers and dairy cows of Holstein breed during estrus. We analysed the locomotion activity and rumination time using the Heatime RuminAct device on 110 dams (78 dairy cows and 32 heifers). We evaluated a total of 298 estrus cycles during the reference period of 3 days before estrus, 3 days after estrus and on the day of the estrus occurrence. The locomotion of cows was expressed in units of locomotion activity in 24 hours (u.24h-1). Rumination time was expressed in minutes in 24 hours (min.24h-1). Based on the results of the study, we established that during estrus, the locomotion activity of dams increases to 888 u 24 h-1 (P <0.001), which represents an increase of +305 u.24 h-1 (+38%). Rumination time of dams was considerably affected by estrus as well and decreased from 582 min.24 h-1 (1 day before estrus) to 482 min.24-1 in estrus time (-43 min.24 h-1).

The accuracy of genomic breeding values (GEBV) for clinical mastitis (CM) of Czech Holstein cattle was analysed. The single-step genomic method and mixed genomic reference populations were employed. Dataset included 92,388 Holstein cows and 160,426 lactations. CM lactation incidence was 19.05%. Cows calved between 2017 and 2022 in 119 herds. A total of 4,969 Holstein sires and 35,814 Holstein females were genotyped. Three genomic matrices were used, two of them encompassing females. The linear animal model with repeatability included fixed effects of herd,year-season and parity_age at calving. The highest average accuracy of GEBV occurred for genotyped cows. SD of GEBV accuracy for bulls was significantly higher than these for cows. The accuracy of genotyped cows with health phenotypes ranged from 0.06 to 0.51. For the genotyped bulls born in 2021 and 2022, maximal accuracy was 0.37; for genotyped heifers, maximal accuracy was 0.42. The highest average GEBV accuracy occurred for the reference population with genotyped bulls and genotyped cows with phenotypes. The average accuracy for the young genotyped bulls increased by 1p. p. when phenotyped cows were considered in the reference genomic population. The cow's GEBV accuracy benefited from including their genotypes in the prediction. It has been confirmed that due to the expansion of the genomic reference population to include a group of genotyped cows with phenotypes, the individual reliability of GEBV for CM has increased.

The study aimed to analyse the claw formation traits in a selected population of Holstein and Slovak Spotted breeds and estimated their heritability and genetic correlation using linear mixed models. Images of the right hind claw were taken during functional claw trimming. NIS Elements 3.0 and MS Excel were used to analyse the images and prepare a database of phenotypic information. Pedigree information of animals was processed using the CFC program. Basic statistical analysis of the variability studied traits was estimated using SAS Enterprise Guide v7.1. Genetic correlation and heritability were estimated using the R package MCMC glmm. Lower average values of claw formation were found for the evaluated Holstein dairy cows compared to the evaluated group of Slovak Spotted dairy cows. The following effects (fixed effects) sire, date of birth, lactation order, calving year, calving season, the season of the claw trimming, and year of claw trimming were evaluated. Both positive and negative genetic correlations were observed between the claw conformation traits in the evaluated dairy cows. In the case of the Holstein breed, the highest positive genetic correlation was found for claw length and diagonal (0.91) and in Slovak Spotted cows for claw width and functional claw area (0.87). Claw conformation traits are generally low heritable, with an average h2 value of 0.30±0.09.

The work evaluates the content of nutrients, rumen digestibility of NDF, degradability of CP, and intestinal digestibility of rumen un-degradable proteins in protein forages and concentrated feeds. The analysis of nutrient content confirmed along with the increase of plant maturity expressed by the increase of NDF, a significant decrease of NFC and CP in the regression dependence R2 = 0.7649 and R2 = 0.7116, respectively. The in situ method after 30 hours of incubation confirmed the higher NDF digestibility (P <0.001) of young roughages. The degradability of CP in alfalfa and grass silages was on average 78.7 ±6.1% or 63.7 ±9.7%. Higher protein degradability was confirmed in early-stage forages compared to mature forages for alfalfa (P <0.05) and grass (P <0.01) silages. Intestinal digestibility of un-degradable proteins determined by the modified three-step method was on average 64.1 ±2.5% in alfalfa silages and 51.0 ±5.6% in grass silages, with a statistically significant decrease (P <0.05) in mature forages. The obtained values of rumen degradability of crude protein confirmed a significant difference (P <0.001) between concentrates ranging from 20.3 to 76.0% (mean 58.1 ±3.0%) according to heat treatment. Intestinal digestibility of un-degraded protein varied from 54.5 ±1.4% in raw soybean to 95.2 ±1.0% in corn gluten feed. This study showed that the digestibility factor of crude protein and intestinal digestibility methods for protein feeds can be used in models to optimize the protein nutrition of dairy cows.

A study of polymorphism of individual genes of milk proteins (kappa-casein and beta- casein) was carried out on the population of cows of the ukrainian brown dairy breed and the sumy interbreed type of the ukrainian black and white dairy breed. Animals of the ukrainian brown dairy breed prevailed in terms of BB genotypes, both for the kappa-casein and genotypes А2А2 for beta-casein genes. According to the complex genotypes of kappa-casein and beta-casein, a difference was established between the animals of the studied breeds. In animals of the ukrainian brown dairy breed a higher frequency is characteristic of the complex genotype A2A2/BB (0.32), and in cows of the sumy interbreed type of the ukrainian black and white dairy breed – A2A2/AA (0.24) and A1A2/AA (0.24).