Hereford Bulls Research Articles

Genotype-Dependent Variations in Oxidative Stress Markers and Bioactive Proteins in Hereford Bulls: Associations with DGAT1, LEP, and SCD1 Genes.

The objective of this study is to assess the influence of genetic polymorphisms in DGAT1, LEP, and SCD1 on the oxidative stress biomarkers and bioactive protein levels in Hereford bulls. A total of sixty-eight bulls were analyzed at 22 months of age to assess growth metrics and carcass quality, with a focus on polymorphisms in these genes. The key markers of oxidative stress, including malondialdehyde (MDA), and the activities of antioxidant enzymes such as glutathione reductase (GluRed), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were measured, alongside bioactive compounds like taurine, carnosine, and anserine. The results show that the TT genotype of DGAT1 is linked to significantly higher MDA levels, reflecting increased lipid peroxidation, but is also associated with higher GluRed and GPx activities and elevated levels of taurine, carnosine, and anserine, suggesting an adaptive response to oxidative stress. The LEP gene analysis revealed that the CC genotype had the highest MDA levels but also exhibited increased GPx and SOD activities, with the CT genotype showing the highest SOD activity and the TT genotype the highest total antioxidant status (TAS). The SCD1 AA genotype displayed the highest activities of GluRed, GPx, and SOD, indicating a more effective antioxidant defence, while the VA genotype had the highest MDA levels and the VV genotype showed lower MDA levels, suggesting protective effects against oxidative damage. These findings highlight genotype specific variations in the oxidative stress markers and bioactive compound levels, providing insights into the genetic regulation of oxidative stress and antioxidant defences, which could inform breeding strategies for improving oxidative stress resistance in livestock and managing related conditions.

Unraveling the Complexities of Beef Marination: Effect of Marinating Time, Marination Treatments, and Breed.

The present study focused on evaluating the effects of beef marination on quality traits and consumer acceptability. In this context, m. longissimus thoracis et lumborum and m. semimembranosus samples (n = 192) were obtained from Aberdeen Angus, Hereford, Charolais, and Limousine bulls and were marinated with milk (pasteurized, 100%), garlic and olive oil (2.35 g/500 mL), and lemon (citrus) juice (31% orange juice, 31% lemon juice, 38% distilled water) for 12, 24, and 72 h. Marinade components were selected based on traditional culinary practices and their scientifically proven effects on meat quality. Beef samples on day 0 and non-marinated samples were used as control groups. Beef color, water holding capacity, pH, cooking loss, and Warner-Bratzler shear force were measured three times for each sample. A taste panel assessment was performed to determine the sensory characteristics. Statistical analysis was performed using general linear model (GLM) procedures followed by Tukey's post-hoc comparison. Results revealed that marination time, as well as its two- and three-way interactions, significantly influenced beef quality parameters. These results indicate that the cattle breed is an important factor in evaluating the effectiveness of beef marination applications. The olive oil-garlic marinade was the most preferred by the panel across both types of muscle, as indicated by sensory evaluation results. The findings will not only enrich the scientific literature but also have practical implications for the beef industry.

Effects of GH L127V and TG5 C422T polymorphisms on the hormonal profile, slaughter traits, and meat quality of Hereford bulls.

The creation of objective methods for the evaluation and improvement of quantitative and qualitative indicators of meat productivity in farm animals should be based on a comprehensive analysis of the genetic, physiological, and biochemical parameters of the animal. This study aimed to investigate the effects of growth hormone (GH) and thyroglobulin (TG5) gene polymorphisms on the hormonal status, slaughter traits, and chemical, amino acid, and fatty acid composition of meat in Hereford bulls. Hereford bulls (n = 9) were reared under the same feeding and housing conditions until the age of 21 months, after which they were slaughtered. Polymerase chain reaction-restriction fragment length polymorphism was performed for genotyping GH L127V and TG5 C422T polymorphisms. The experimental animals were evaluated to determine slaughter traits (including pre-slaughter weight, carcass, and internal fat weight and yield), chemical, fatty acid, and amino acid composition of ground beef, and hormonal status using serum concentrations of GH, triiodothyronine, and thyroxine. Animals with the valine homozygous (VV) genotype of GH had the maximum serum GH level of 9.33 mIU/mL (p = 0.10) higher than leucine homozygous (LL) genotype carriers. Individuals with the LL genotype outperformed V-allele carriers in serum thyroxine (T4) concentration by 21.3-30.5 nmol/L (16.15%-24.86%; p < 0.01-0.05). Genetic differentiation induced by TG5 C422T polymorphism was determined to a lesser extent by the hormonal status of the Hereford animals. The V-allele was associated with increased carcass weight, with VV homozygotes significantly outperforming LL individuals by 45.0 kg (13.61%; p < 0.05). The T allele at the TG5 gene polymorphism was associated with more intense lipogenesis and less protein synthesis in muscle tissue and these effects were enhanced in the homozygous state. Young animals with the TT variant of the TG5 gene exhibited a significantly superior polyunsaturated fatty acid/saturated fatty acid ratio of 0.012 units (p < 0.01). Carriers of the LL genotype were characterized by minimum amino acid content in muscle tissue. Heterozygous bulls exceeded LL homozygotes in the sum of essential amino acids by 3.09% (p = 0.10) and non-essential amino acids by 1.9% (p < 0.05). The development of breeding programs for the Hereford breed should be carried out considering genetic features that determine the formation of economic traits in animals. Analysis of polymorphisms in the TG5 gene is a promising method for the early diagnosis of the fatty acid composition of beef. Identification of polymorphisms in the GH gene allows the prediction of higher productivity potential and amino acid composition of meat. The different effects of the GH and TG5 genes on the development of various economic traits allowed us to determine further vectors for scientific research on their complex associations in Hereford cattle, which will be useful for planning effective breeding schemes.

Intake, gain and carcass traits of Hereford and Simmental bulls offered total mixed rations based on red clover and whole-crop barley silages

Intake, gain and carcass traits of Hereford and Simmental bulls offered total mixed rations based on red clover and whole-crop barley silages

Pharmacokinetics of florfenicol in serum and seminal plasma in beef bulls

The objectives of this study were to compare the serum and seminal plasma pharmacokinetic profiles of florfenicol (FLO) and florfenicol amine (FLA) after the administration of FLO either by IM or SC routes in beef bulls. Four clinically healthy Hereford bulls underwent a comprehensive physical exam, including breeding soundness examination, CBC, and chemistry profile panel. Bulls were healthy and classified satisfactory potential breeders. In one group (n = 2), a single dose of FLO was administered SC in the middle of the neck at a dose of 40 mg/kg of body weight. In the second group (n = 2), a single dose was administered IM in the muscles of the neck at a dose of 20 mg/kg. Concentrations of FLO and FLA in serum and seminal plasma were determined by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Blood and semen samples were collected before the administration of FLO and at 12, 24, 36, 48, 72, 96, 120, 144, and 168 h after injection. The blood was collected from the coccygeal vessels, and semen was collected by electroejaculation. All samples were immediately refrigerated, processed within the first hour after collection, and finally stored at −80 °C. The mean level of total FLO in serum was higher when administered by the SC route (1,415.5 ng/mL) than by the IM route (752.4 ng/mL; P = 0.001). Differences were observed between the percentage of FLA in serum (1.8%; ranging from 1.3 to 2.9) and in seminal plasma (27.5%; ranging from 15.9 to 34.2; P = 0.0001). The mean level (±SD) of FLA was higher in seminal plasma compared to serum (467 ± 466 ng/mL and 18 ± 16 ng/mL, respectively; P = 0.001). The mean level of total FLO in seminal plasma was 1,454.8 ng/mL for the SC route and 1,872.9 ng/mL for the IM route without differences between the two routes (P = 0.51). Differences in the mean level of total FLO between serum and seminal plasma were detected (1,187 ± 2,069 ng/mL and 1,748 ± 1,906 ng/mL, respectively; P = 0.04). From the present investigation, it was concluded that FLO is a suitable antibiotic based on its pharmacokinetic attributes and may be employed for the treatment of bull genital infections when its use is indicated. To study the pharmacokinetics of FLO in seminal plasma, the analysis of FLA should be incorporated.

Relationship between blood biochemical parameters and beef quality indicators in Hereford bulls

The aim of this study was to investigate the relationship between blood serum biochemical composition and hormonal status of Hereford bulls and beef quality indicators. The object of the study was Hereford bulls (n=9) aged 20-21 months. AST activity was positively correlated with the amount of fat (r=0.70; P&lt;0.05), whereas a similarly strong but inverse relationship (r=-0.87; P&lt;0.05) was found with the moisture content in beef. A significant negative correlation (r=-0.71; P&lt;0.05) was found between thyroxine content and linolenic fatty acid. The most significant correlation of palmitic (r=0.72; P&lt;0.05) and oleic FA synthesis (r=-0.72; P&lt;0.05) was observed with total protein content. Tyrosine, cholesterol and triglyceride levels were negatively correlated with amino acid composition. Moreover, the association of thyroxine with methionine (r=-0.76; P&lt;0.05), triglycerides with arginine (r=-0.82; P&lt;0.05), methionine (r=-0.68; P&lt;0.05) and threonine (r=-0.69; P&lt;0.05) reached significant values in terms of strength. These summary tests objectively describe the peculiarities of synthetic and metabolic processes in the bovine body. A complex approach to predicting the biological value of beef based on correlation with physiological and biochemical indices of blood in young Hereford cattle has been applied to increase the efficiency of selection and breeding work in beef cattle breeding.

Beef production in conditions of stable-pasture and industrial technologies in breeding farms

The article presents data on the comparative study of beef production in the conditions of stable-pasture and industrial technologies. For this purpose, in the first series of experiments in the breeding farms of Antonovskoye CJSC and Energia LLC, 40 black-and-white bulls (group 1), Kalmyk (group 2) and Hereford breeds (group 3) were formed. Black-and-white bulls were individually kept in a dispensary, 15-day-olds were grouped into 20-30 heads and were tied up in a calf coop using farm pastures. Calmyk and Hereford bulls up to 7-8 months of age were raised in both farms with mothers on full suckling. After weaning from mothers, 20 8-month-old bulls from each group were kept together, in conditions of stable-pasture technology with the expectation of obtaining 800-900 grams of daily gain. 20 8-month-old bulls of each group for the second series of tests were implemented for rearing at the Agro-Park-Razvilnoye industrial complex LLC and had free access to self-feeders with concentrates and coarse feed. In the first series, the daily increase was 749-804 g, and in the second series – 1275-1360 g, with an advantage in favor of gerefords. Therefore, the live weight of 18-month-old bulls, respectively, by birth was 619.0; 646.6 and 657.7 kg, or 178-192 kg more than with stable-pasture technology (P&gt;0.999). At the control slaughter, the Herford bulls were highly reliably superior in both series of experiments in terms of carcass weight, muscle tissue and slaughter yield. However, the profitability of production in the first series of experiments is 1-2% higher, and the live weight is 29-30% lower.

Влияние генотипа крупного рогатого скота на химический состав говядины

Purpose. To study the slaughter qualities of mixed young cattle and the chemical composition of beef obtained from it. Materials and Methods. The object of research is 18-month-old crossbred bulls, obtained as a result of industrial crossing of Kazakh white-headed cattle bulls with heifers of the Simmental breed (group I), Hereford bulls with heifers of the Simmental breed (group II) and Kalmyk bulls with heifers of red steppe cattle (group III). Purebred bulls of the Kazakh white-headed breed were used as a control group. Chemical analysis of beef samples was carried out according to the following methods and GOST standards: moisture content was determined by drying the sample to a constant mass at a temperature of 100-105 °C according to GOST 9793-2016; protein content – by the amount of protein nitrogen by the Kjeldahl method according to GOST 25011-2017; fat content – according to GOST 23042-2015; ash content – according to GOST 31727-2012; the amino acid and vitamin composition was determined according to the method of measuring the mass fraction of amino acids and vitamins by the KE method on the Kapel-105M system, the concentration of hydrogen ions (pH) according to GOST R 51478-99. Calorie content of 100 g / meat was calculated using the formula of V. M. Aleksandrov. Results. To assess the meat productivity of crossbred steers, their control slaughter was carried out, which showed that the largest slaughter weight and slaughter yield were possessed by steers of the II experimental group – 312.4 kg and 61.0%. Beef samples from young animals of the II experimental group had the highest content of dry matter. The difference with peers from the control, I and III groups was 0.27, 0.21 and 0.63%, respectively. It was also noted that the crossbred young of the II experimental group surpassed purebred Kazakh white-headed bulls in protein content by 1.67%. The difference with the crossbreeds from group I and III is 1.38 and 2.3% respectively. A study of the vitamin composition of the beef of experimental young animals showed that the resulting beef was relatively rich in vitamins of group B. beef obtained from crossbred bulls of the II experimental group has a higher biological value (Protein qualitative indicator = 5.86 compared with the control 5.59). The increase in protein qualitative indicator is mainly due to the higher content of tryptophan in beef of the experimental group II – by 9.0% (494.40 mg% compared with 453.86 mg% in the control). The pH value of the water-meat extract in bulls of different genotypes is almost the same and ranged from 5.41 to 5.49. Conclusion. It has been established that the crossing of bulls of meat breeds of cattle with heifers of dairy and combined breeds contributes to the production of young offspring with excellent slaughter qualities, and beef obtained from such offspring has a high biological value.

249 The Effects of Breed and Early Supplementation on Bovine Intramuscular Fat Deposition, Adipogenic and Lipogenic Gene Expression

Abstract Wagyu cattle are known to deposit greater amounts of intramuscular fat, which can directly increase quality grade and carcass value. Supplementation can positively influence animal production and overall nutrient acquisition when used strategically. The objectives of this study were to evaluate 1) the effect of breed and early supplementation on intramuscular and subcutaneous fat deposition in Wagyu and Hereford cross calves, and 2) changes in adipogenic and lipogenic gene expression in longissimus muscle (LM) biopsies from Wagyu and Hereford cross calves during an early supplementation period. Angus cows (n = 34) were artificially inseminated with semen from a Wagyu bull. A Hereford bull was utilized as a clean-up bull. From this breeding, Wagyu cross steers (n = 8) and Hereford cross steers (n = 9) were produced and were placed on study on day 100 of age. At this time, calves were allowed access to four SuperSmart Feeder stalls and were individually supplemented with steam-rolled corn at 0.5% body weight (BWT). Calves were ultrasounded on day 0, day 43, and day 86 of the study to evaluate intramuscular fat deposition and backfat thickness. An longissimus muscle (LM) biopsy was taken on day 0 and day 86 of the study to evaluate gene expression. Supplemented steers tended (P &amp;lt; 0.10) to have more backfat than non-supplemented steers. Intramuscular fat amount differed (P &amp;lt; 0.05) by breed, while ribeye area tended (P &amp;lt; 0.10) to differ by breed. Wagyu exhibited a greater (P &amp;lt; 0.05) amount of intramuscular fat at the beginning and at the end of the study. Breed did not (P &amp;gt; 0.05) influence backfat thickness. Neither breed nor supplementation affected (P &amp;gt; 0.05) average daily gain or final body weights. Platelet-derived growth factor alpha (PDGRFA) and SREBP cleavage-activating protein (SCAP) differed (P &amp;lt; 0.05) between biopsy phases. Fatty acid binding protein-4 (FABP4) and stearoyl-coA desaturase-1 (SCD1) did not differ (P &amp;gt; 0.05) between breed or biopsy phase. In conclusion, changes in gene expression could indicate enhanced preadipocyte proliferation during this stage of calf development. Overall, supplementation altered backfat deposition but did not alter intramuscular fat levels. Opposingly, sire breed influenced intramuscular fat levels at an early age. A deeper understanding of the physical and molecular effects of supplementation and sire breed could provide additional avenues for manipulating adipose tissue.

390 Colorado State University Seedstock Merchandising Team: Creating Impactful Student Experience and Engagement in the Beef Industry

Abstract Hands-on learning is not a new term for animal science curriculums; in fact, it is often something that sets the major apart. The demand for experiential learning opportunities continues to be strong. Students not only want more experience with livestock, but also learning opportunities that provide impact: labs, field trips, internships, and research for example. Colorado State University is committed to providing unique student opportunities that allow students to gain new perspectives, practice applying foundational knowledge, strengthen professional networks, and grow as young leaders in the agriculture and livestock industries. The CSU Seedstock Merchandising program was founded in 1976 under the direction of Dr. Robert Taylor. Taylor’s work focused on beef cattle systems and management, and he believed that learning happens in and out of the classroom. This philosophy built a long tradition of “learning by doing”. In the spring of 1977, the first group of “Advertising and Merchandising Breeding Cattle” students advertised and sold 17 head of yearling bulls with a sale average of $1,600. In the spring of 2023, the CSU Seedstock Merchandising Team hosted the forty-sixth annual sale selling 28 head of age-advantaged Angus and Hereford bulls averaging $4,196 and 9 Hereford and Commercial Angus bred females averaging $2,639. In the years between these two events, the program expanded. Beginning in 2002, student activities extended beyond organizing and advertising a sale. It was at this time that students began exhibiting cattle at the National Western Stock Show and participating in the National Cattlemen’s Beef Association Convention and Trade Show through hosting a booth on behalf of the CSU Animal Sciences Department. In addition to these activities, students on the Seedstock Merchandising Team are required to register for a series of courses focused on seedstock cattle merchandising and management. These students work extensively with the records of the on-campus teaching herd participating in data collection and management, preparing data for submission to breed associations, making recommendations for annual breeding and selection, as well as management and marketing. Beef industry leaders and fellow seedstock producers are invited into the classroom as guest speakers. Students travel to seedstock operations and sales, study online sales and marketing, practice social media promotions, collect data for the sale catalog, set sale order, identify animals to highlight and photo, as well as host the sale and write a sale report. It is through these experiences that students are developing skills that can be used across a range of careers while also practicing animal husbandry and management knowledge gained across the animal sciences curriculum. Students active in the seedstock program have the opportunity to strengthen data analysis and management, communication, networking, and time management skills, as well as practicing community and industry engagement and industry advocacy.

DEVELOPING MEAT PRODUCTIVITY IN BULL CALVES OF DIFFERENT DGAT1 GENOTYPES

The given research aims to study the way meat productivity in special-purpose beef bull calves of different DGAT1 genotypes is developed. The scientific novelty of the research lies in the fact that an assessment of the meat productivity of Hereford and Limousin bulls of different DGAT1 genotypes was conducted for the first time. Calves were cultivated using elements of resource-saving technology. The research subject was Hereford male young stock (91 heads) and Limousin bull calves (109 heads), which were genotyped by SNP DGAT1-K232A. Live weight, average daily gains, and body size and conformation indices were analyzed. Hematological values and carcass quality of bull calves of different genotypes were studied. As a result of genotyping, young animals of both breeds had a similar distribution of genotypes (DGAT1KK&gt;DGAT1KA&gt;DGAT1AA) and alleles (DGAT1K&gt;DGAT1A). There was no effect of the studied gene polymorphism on growth, body development, and hematological parameters, as bull calves of different DGAT1 genotypes did not show a significant difference between weight and linear growth, blood morphological parameters, the content of protein, and its fractions. SNP DGAT1-K232A was found to affect fat deposition. Thus, carcasses of both studied breeds of DGAT1K genotype had a significantly higher content of internal raw fat, and fat yield was (P&lt;0.05) than carcasses of DGAT1AA genotype bull calves. Therefore, genotyping by SNP DGAT1-K232A can be used in the selection of special-purpose beef cattle as an additional criterion to produce meat of a higher energy value.

Integrated assessment of bulls of precocious meat breeds of English selection in the conditions of Ukraine

An integrated assessment of the productivity of precocious Hereford and Aberdeen Angus beef bulls of English breeding in the Ukraine Steppe zone conditions was carried out. It has been established that livestock from the seaside climate have adapted to the dry, hot environment of the Steppe zone, as evidenced by the clinical indicators of the animals’ bodies. Livestock developed harmoniously, external measurements and indices of body structure were within the limits of breed standards. Hereford and Aberdeen Angus breeds bulls under pasture-free maintenance and rearing conditions for up to 2.5 years at the end of fattening had high productivity — 688 and 531 kg of body weight, respectively. The bulls were with a harmoniously developed body and perfectly expressed meat forms. The bulls were of compact build with a developed deep chest, a full back part of the body, which is characteristic of cattle with a strong constitution and potentially high meat productivity. The relative growth rate of the bulls during the study was in the range of 19–22%. Therefore, Hereford and Aberdeen Angus breeds are the future of meat cattle breeding in Ukraine to increase the production of high-quality “marble” beef. Compared to Aberdeen Angus, Herefords differ in slightly larger habit, massiveness, growth energy, feed conversion, slaughter indicators, balanced morphological composition of carcasses, meatiness ratio. Absolute and relative increases in body weight confirm the high genetic potential of meat productivity — 18–24-month-old bulls have reached sales conditions. Today, their number is small, and reproduction requires a certain amount of time and money, so we believe that the breeding period can be extended to 30 months. In the period of formation of the meat cattle breeding industry, it is possible to raise young animals up to 30 months of age without deterioration of slaughter performance and culinary and taste qualities of beef in accordance with consumer requirements.

Prediction ability of an alternative multi-trait genomic evaluation for residual feed intake.

Selection for feed efficiency is the goal for many genetic breeding programs in beef cattle. Residual feed intake has been included in genetic evaluations to reduce feed intake without compromising performance traits as liveweight, body gain or carcass traits. However, measuring feed intake is expensive, and only a small percentage of selection candidates are phenotyped. Genomic selection has become a very important tool to achieve effective genetic progress in these traits. Another effective strategy has been the implementation of multi-trait prediction using easily recordable predictor traits on both reference animals and candidates without phenotypes, and this could be another inexpensive way to increase accuracy. The objective of this work was to analyse and compare the prediction ability of two alternative different approaches to predict GEBVs for RFI. The population of inference was Hereford bulls in Uruguay that were genotyped candidates for to selection. The first model was the conventional univariate model for RFI and the second model was a multi-trait model which included a predictor trait (weaning weight, WW), in addition to the traits used in the first one (dry matter intake, metabolic mid test weight, average daily gain and ultrasound back fat) (DMI, MWT, ADG, UBF, respectively). GEBVs from the multi-trait model were combined using selection index theory to derive RFI values. All analyses were performed using ssGBLUP procedure. The prediction ability of both models was tested using two validation strategies (30 different replicates of random groups of animals and validation across 9 different feed intake tests). The prediction quality was assessed by the following parameters: bias, dispersion, ratio of accuracies and the relative increase in accuracy by adding phenotypic information. All parameters showed that the univariate model outperforms the multi-trait model, regardless of the validation strategy considered. These results indicate that including WW as a proxy trait in a multi-trait analysis does not improve the prediction ability when all animals to be predicted are genotyped.

Influence of paratypes factors on the level of zinc in the lungs of the Hereford breed

The study aims to evaluate the influence of the ecological and geographical factors on the zinc content of light Hereford bulls and calculate the reference intervals for this metal. Lung samples weighing 100 g were taken from clinically healthy bulls of the Hereford breed in the Maslyaninsky, Novosibirsk and Krasnozersky districts of the Novosibirsk region and the Tselinny district of the Altai Territory. The chemical composition of lung tissues was determined by atomic absorption spectrometry with electrothermal atomization. The homoscedasticity of dispersions in groups was assessed using the Fligner-Keelin test. The influence of the factor was determined using the Kruskal-Wallisl test. Multiple intergroup comparisons were made using Dunn’s test and Holm’s correction. The maximum zinc level was found in animals bred in the Maslyaninsky district (26.6 mg/kg) and the minimum – in Krasnozersky (13.8 mg/kg). Cattle from the Maslyaninsky district are characterized by higher phenotypic variability in zinc content in the lungs than in other areas. Generally, the variability of the studied metal in the lungs of gobies is relatively low. Group variances in the zinc level in cattle lungs are homoscedastic (x2 =2.27; P=0.518). The influence of the ecological and geographical factors on the zinc level in Hereford cattle’s lungs was established (H = 12.158; P = 0.007). The concentration of metal in the lungs of bulls from the Krasnozersky district is statistically significantly different from cattle from Maslyaninsky (Z = -2.96; P = 0.009). There were no statistically significant differences in Zn concentration in lung tissues between animals from other regions. Reference intervals for the content of zinc in the lungs of Hereford cattle in the conditions of the south of Western Siberia are 12.44-24.12 mg/kg, with 90% confidence intervals for the lower limit of 10.15-13.66 mg/kg and the upper limit of 22.73 -26.49 mg/kg.

РЕЗУЛЬТАТЫ ПРОМЫШЛЕННОГО СКРЕЩИВАНИЯ КРАСНОГО СТЕПНОГО СКОТА С ЧИСТОПОРОДНЫМИ БЫКАМИ ГЕРЕФОРДСКОЙ ПОРОДЫ ПРИ РАЗНЫХ ТЕХНОЛОГИЯХ ПРОИЗВОДСТВА ГОВЯДИНЫ

The purpose of the research was to establish the effectiveness of breeding crossbreed bulls of the 1st generation, obtained by industrial crossing of Hereford bulls with red steppe cattle, in a comparative aspect with their red peers with different beef production technologies adopted in cattle breeding. The first control group included calves of the red steppe breed (n = 10), the second – first-generation crossbreeds from the crossing of red steppe cattle with Hereford bulls (n = 10), raised according to the dairy cattle breeding technology adopted on the farm. The first experimental group of calves was formed from animals of the red steppe breed (n = 10), the second – F1 crossbreeds (red steppe × Hereford) (n = 10). It was found that the bulls of the experimental groups by the age of 18 months had reached a live weight exceeding the values of the control groups by 59,1–73,8 kg (P &gt; 0,999). The experimental groups of bull calves outperformed their control peers by an average of 114–135 g (P &gt; 0,999) in terms of average daily live weight gains over the entire study period. With the same feed costs per unit of live weight gain, the largest gross increase was typical for individuals of the experimental groups. According to the main indicators of the control slaughter, the superiority was on the side of steers raised according to the beef production technology adopted in beef cattle breeding. With both cultivation technologies, the highest yield of carcass and fat was obtained from Hereford × red steppe bulls, which provided a greater slaughter yield (by 2,8–3,0 %) in comparison with peers of the red steppe breed.

Phenotypic and genetic relationships for feed intake, feed efficiency, body composition and cow milk yield measured postweaning and in mature beef cows

Context Providing feed is the largest cost in beef production. Genetic variation exists in feed efficiency traits in young cattle but the genetic associations with feed efficiency traits in cows are poorly understood, but if strong and favourable, they might be used to improve feed efficiency of cows. Aim To examine the phenotypic and genetic relationships among feed intake, feed efficiency, body composition and cow milk yield measured in young cattle and in cows. Methods Data on 1783 young Angus, Hereford, Polled Hereford and Shorthorn bulls and heifers, and for 751 of the females as cows, were used to calculate the phenotypic and genetic relationships among feed efficiency traits, body composition and cow milk yield measured postweaning and in mature cows. The young cattle were tested for feed intake and feed efficiency at approximately 9 months of age and the females, after two calvings, were tested again as non-pregnant, non-lactating cows at approximately 4 years of age. Key results At the postweaning test, the heritability estimates for feed intake, average daily gain, test weight, residual feed intake (RFI), feed conversion ratio, rump fat depth and eye-muscle area were 0.47, 0.32, 0.46, 0.42, 0.28, 0.47 and 0.20 respectively. Corresponding heritability estimates in the cow test were 0.27, 0.35, 0.74, 0.22, 0.30, 0.47 and 0.12. Heritability estimates for 400-day weight, cow 4-year weight and cow milk yield were 0.47, 0.62 and 0.15 respectively. Genetic correlations between traits measured postweaning and the same traits measured in the cow were moderate to high, and for the feed efficiency trait, RFI, was very high (0.95), close to unity. Conclusions Inclusion of postweaning RFI as a selection criterion in beef cattle breeding can be expected to lead to improvement in cow feed efficiency. Implications Most breeding decisions in beef cattle are based on traits measured early in life and for replacement heifers are made with an aim to improve their productivity and profitability as cows. The strong and favourable associations measured between postweaning RFI and cow RFI mean that feed efficiency measured in young cattle can be used as a selection trait to improve cow feed efficiency.

Growth, Carcass, Organ Characteristics and Meat Quality of Crossbred Steers from Kalmyk Cows and Kalmyk, Simmental, Hereford, and Kazakh White Headed Bulls

Growth, Carcass, Organ Characteristics and Meat Quality of Crossbred Steers from Kalmyk Cows and Kalmyk, Simmental, Hereford, and Kazakh White Headed Bulls

PSXII-2 Effect of TG5 (c.-422C&amp;gt;T) Polymorphism on Fatty Acid Composition of Muscle Tissue in Bull

Abstract Intensive fat deposition is accompanied by an increased synthesis of saturated and monounsaturated fatty acids, resulting in a decrease in the proportion of polyunsaturated fatty acids in muscle tissue. The TG5 (c.-422C &amp;gt;T) polymorphism is associated with fat metabolism in Bos Taurus. The aim of the research was to study the effect of TG5 (c.-422C &amp;gt;T) polymorphism on fatty acid composition of muscle tissue in Hereford bulls. Polymorphism TG5 (c.-422C &amp;gt;T) was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. The fatty acid composition of lipids was determined by gas-liquid chromatography on a “Kristall-4000 Lux” chromatograph (Russia). Hereford bulls were slaughtered at 15 months of age. Two groups of bulls with TG5CC and TG5CT genotypes were formed according to the results of genotyping. The total share of SFA and MUFA in muscles of bulls with the TG5CC genotype was 71.2% and exceeded indicators of their peers by 1.0%. These data were consistent with increased synthesis of inter- and intramuscular fat, as well as subcutaneous adipose tissue. The TG5CT genotype was associated with better fat quality in terms of essential fatty acids content, which accounted for 29.8%. Bulls with TG5CT genotype outperformed their peers in content of palmitic by 0.74% and behenic by 0.02% among saturated fatty acids, palmitoleic by 0.67% among monounsaturated fatty acids, linoleic by 1.07%, linolenic by 0.15 % and arachidonic by 0.05% among polyunsaturated fatty acids. The maximum content of stearic (by 1.72%) and oleic (by 0.72%) fatty acids was observed in the group with the TG5CC genotype. The greatest (by 0.08 units) ratio of unsaturated to saturated fatty acids indicated the best quality of adipose tissue in TG5CT bulls. Thus, the increased intensity of fat deposition in TG5CC carriers had a negative impact on the quality of meat.

Influence of tropical, subtropical, and temperate climate conditions on seminal redox status and sperm quality parameters in breeding bulls

This study evaluated the effect of climate change on andrological parameters of beef bulls raised under tropical, subtropical, and temperate conditions. Bull ejaculates were collected to evaluate seminal quality parameters, sperm membrane integrity, and redox status (SOD; GPx; GSH; GRx; CARB; DCF; and SOD/GPx ratio). Bulls located in the temperate region showed a higher sperm motility rate and percentage of viable sperm (P < 0.05). When evaluating regions independently, we observed a lower GPx activity from animals in the tropical region (P < 0.05). In contrast, we found that SOD and GRx activities, GSH content, and CARB oxidative levels were higher in the tropical region, while oxidation values of DCF were lower (P < 0.05). Braford bulls showed higher CARB and DCF levels (1.23 ± 0.61 nmol/mg and 1453.60 ± 828.63 nmol/mg, respectively) compared to Hereford bulls (1.00 ± 0.43 nmol/mg and 1138.70 ± 423.24 nmol/mg, respectively) in the temperate region. However, Nellore bulls showed higher DCF levels (650.50 ± 401.53 nmol/mg) than Braford bulls (409.40 ± 286.97 nmol/mg). In addition, the SOD/GPx ratio was lower in Braford (12.44 ± 7.64 U/mg) compared to Nellore bulls in tropical conditions (87.25 ± 2.83 U/mg). A positive correlation was found in temperate conditions between DCF levels, SOD, and GRx activities (0.51, 0.58; P < 0.01, respectively), as well as in subtropical conditions between DCF levels and GRx activity (0.53; P < 0.01). A negative correlation between the temperature-humidity index and CARB content was found in subtropical and tropical regions (−0.44; P < 0.01). We concluded that Braford breeds showed lower seminal motility, DCF contents and SOD/GPx ratios compared to Nellore bulls in tropical climate conditions. Finally, in temperate environmental conditions, Braford bulls also showed lower seminal motility but higher levels of CARB and DCF contents compared to Hereford bulls. Therefore, the existence of climatic differences between the temperate and tropical regions evaluated affected Braford bulls’ seminal motility and seminal redox homeostasis.

MEAT PRODUCTIVITY OF FRENCH-BRED BULLS DUE TO ADAPTIVE TECHNOLOGY IN WESTERN SIBERIA

The study of meat productivity of introduced cattle breeds in Western Siberia using adaptive technologies is of scientific and practical interest. We carried out the experiment on five cattle groups of Hereford, Limousin, Charolais, Aubrac and Salers bull calves. Furthermore, we determined the indicators of weight growth from birth to 18 months and meat productivity at the age of 18 months. At birth, live weight control was carried out at 3, 6, 9, 12, 15 and 18 months when weighing animals in the morning before feeding and watering. We studied meat productivity during the control slaughter of animals at the Yalutorovsky meat processing plant. Three heads from each group were slaughtered. The slaughter was carried out according to the Lenin All-Union Academy of Agricultural Sciences [VASKhNIL] method. The experimental material was processed by the method of variation statistics using the Microsoft Excel software application. Steers of French meat breeds surpass Hereford cattle breeds in terms of live weight and average daily growth. The carcass weight of Charolais animals is 329.5 kg, which is 75.3 kg more than in Hereford bulls, P≥0.999. The results of the chemical analysis indicate that the highest fat content is contained in the minced meat of Hereford bulls – 10.6%. Introduced cattle breeds, when bred under new conditions, showed a fairly high level of meat productivity, carcasses were obtained during slaughter, with an optimal ratio of tissues and chemical composition of carcasses, in terms of the yield of edible parts in the carcass and the meat content coefficient, they surpass the Hereford cattle breed. Thus, French meat breeds are promising for beef production in Western Siberia.