Young Bulls Research Articles

Summer heat during spermatogenesis reduces in vitro blastocyst rates and affects sperm quality of next generation bulls.

Due to global warming seasonal heat stress is an increasing problem in temperate zones. Heat stress not only decreases fertility in females, but can also be detrimental to male fertility. We studied the effects of natural summer heat stress during spermatogenesis in Holstein bulls on semen quality parameters and on fertilization performance in vitro and possible intergenerational transmission of effects on the next male generation. Semen samples from young Holstein breeding bulls, referred to as F0 founders during this study, were collected during summer (F0 "summer" semen) and the following winter (F0 "winter" semen). Parameters such as ejaculate volume, sperm density, motility, thermoresistance, and in vitro blastocyst rates from these F0 semen samples were determined. In addition, after generation of offspring by artificial insemination, semen samples from F1 male offspring were collected and tested for the same quality and performance parameters to capture intergenerational effects. F1 bulls were raised together under identical conditions and semen was collected at about 1 year after birth. The data showed that in vitro blastocyst rates of F0 "summer" semen samples were lower compared with "winter" semen, whereas blastocyst rates of F1 semen samples did not show significant differences. However, whereas F0 semen samples did not indicate significantly different quality parameters we found that motility of F1 semen samples showed significant differences with higher values when collected from bulls generated with F0 "winter" semen. From our data, we conclude that (i) natural summer heat stress during spermatogenesis can affect in vitro fertility parameters and (ii) the observed effects on sperm motility of F1 semen samples suggest intergenerational paternal transmission.

Muscle biopsy long-chain omega-3 polyunsaturated fatty acid compositions, IMF and FMP in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu Beef Cattle

BackgroundWe investigated breed and gender variations in the compositions of long-chain (≥ C20) omega-3 polyunsaturated fatty acids (LC omega-3 PUFA), fat melting point (FMP) and intramuscular fat (IMF) contents in biopsy samples of the M. longissimus dorsi muscle of grazing beef cattle. The hypothesis that biopsy compositions of health-beneficial LC omega-3 PUFA, FMP and IMF in a pasture-based production system will vary with breed, was tested. Muscle biopsies were taken from 127 yearling pasture-based Angus, Hereford, and Wagyu heifers and young bulls exclusive to the Australian Bowen Genetics Forest Pastoral breeding stud averaging 12 ± 2.43 months of age and under the same management routine.ResultsBreed had a significant influence on IMF, FMP, and the compositions of oleic acid, α-linolenic acid (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA), docosapentaenoic (DPA), and total EPA + DHA + DPA in the M. longissimus dorsi muscle biopsies (P ≤ 0.03). The Wagyu breed had the highest (11.1%) and Hereford the lowest (5.9%) IMF (P = 0.03). The reverse trend was observed in FMP values where the Hereford breed had the highest (55 °C), Angus intermediate (46.5 °C), and Wagyu the lowest (33 °C) FMP. The Wagyu and Angus breeds had similar oleic fatty acid (18:1n-9) content, while the Hereford breed had the lowest (P < 0.01). The highest ALA, DPA, total EPA + DHA, total EPA + DHA + DPA and total ALA + EPA + DHA + DPA contents were detected in the Wagyu breed (P ≤ 0.03). The Hereford had similar EPA and DPA contents to the Angus (P ≥ 0.46). Total EPA + DHA + DPA contents in Wagyu, Angus, and Hereford were 28.8, 21.5, and 22.1 mg/100g tissue (P = 0.01), respectively. Sex was an important source of variation that influenced LC omega-3 PUFA composition, FMP and IMF, where yearling heifers had higher IMF (11.9% vs 5.3%), lower FMP (33°C vs 37°C), and higher LC omega-3 PUFA than bulls.ConclusionAll the results taken together indicate that the Wagyu breed at 28.8 mg/100g tissue, was the closest to meeting the Australia and New Zealand recommended source level threshold of 30 mg/100g tissue of health-beneficial ≥ C20 omega-3 FA content. Since gender was a significant determinant of LC omega-3 PUFA composition, IMF content and FMP, it should be factored into enhancement strategies of healthy meat eating quality traits in grazing cattle. These findings also suggest that the Bowen Genetics Forest Pastoral beef cattle studs are important sources of LC omega-3 PUFA that can be used to cover the deficit in these health claimable fatty acids in Western diets.

An investigation of slaughter weight and muscle type effects on carcass fatty acid profiles and meat textural characteristics of young Holstein Friesian bulls

Study objectives included the assessment of carcass fatty acid composition and meat texture characteristics of younger Holstein Friesian bulls. Three experimental groups were formed based on the weights of the 23 young bulls at slaughter: lighter, medium, and heavier. Samples were taken from the Gluteus medius (GM) and Longissimus thoracis muscles 24 h after slaughter. Fatty acid composition, Warner-Bratzler Meat Shear (WBS) measurements, as well as textural profile analysis (TPA) and sensory analysis of the muscle samples were conducted. The fatty acid composition was determined using Thin Layer Chromatography (HPTLC). Polyunsaturated fatty acids and dietary fatty acids give a neutral hypocholesterolemic effect in direct fluorescent antibody (DFA) contents, DFA/OFA (C14:0+C16:0) ratio, hardness, Warner-Bratzler Shear force and also the chews number – which is desirable - before swallowing (NCBS) the meat were significantly decreased with the increasing slaughter weight. Higher slaughter weight resulted in a larger amount of beef with a better panel tenderness score; however, the meat obtained from the LSW group was less healthy considering the fatty acid profile. Additionally, internal fat contained the highest saturated fatty acids concentrations, while subcutaneous fat contained the highest amount of monounsaturated fatty acids. Furthermore, intramuscular fat levels were highest in PUFA and PUFA/SFA ratio. As a result, this study strongly suggests that slaughter weight and anatomical location of fat samples contribute significantly to meat texture characteristics and fatty acid profiles in Holstein Friesian bulls.

Effects of Early Weaning on Performance and Carcass Quality of Nellore Young Bulls.

This study compared early weaning (EW; 150 days) with conventional weaning (CW; 240 days) in Nellore young bulls, evaluating performance, carcass characteristics, and meat quality. A total of 74 non-castrated male calves were divided into two weaning strategies: EW (n = 37) and CW (n = 37). During the growth phase, which lasted 454 ± 14 d for EW calves and 359 ± 16 d for CW calves, animals received a protein-energy supplement at a ratio of 5 g per kg of body weight while grazing Brachiaria brizantha cv. Marandu. The animals were managed for an 87d finishing phase in three collective feedlot pens, with a 3-week adaptation protocol, starting with corn silage to a concentrate ratio of 55:45 and reaching a ratio of 30:70 in the final diet. Body weight, average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE), carcass characteristics, and meat quality were evaluated. The EW group was approximately 44 kg lighter than the CW at the time of conventional weaning (p < 0.001). However, this weight difference did not influence ADG, DMI, and FE in the finishing phase. No significant differences were observed in carcass characteristics such as yield percentage, loin area, subcutaneous fat thickness, and meat quality, except for the weight of primal cuts, which was greater in the CW group (p < 0.001). Thus, although calves weaned early are lighter throughout subsequent production phases than those weaned conventionally, performance, efficiency, carcass yield, and meat quality are not affected.

Nutrient intake, productive and metabolic parameters of Nellore bulls feed a forage free diet using cottonseed cake as a fiber source.

We hypothesized that cottonseed cake in confined Nellore young bulls' diet as fiber source, could maintain or improve the nutrient intake, and productive and metabolic parameters. It was evaluated the total replacement of whole plant corn silage (WPCS) by cottonseed cake (CSC) as a source of fiber in the diet. A completely randomized design with two treatments and 12 replications was used. The treatments were two experimental diets containing 300g/kg of WPCS or CSC as roughage. All animals at 0, 15, 30, 60 and 112days were weighed to monitor productive performance and nutrient intake. Dry matter intakes, organic matter, neutral detergent fiber, physically effective neutral detergent fiber, crude protein and non-fiber carbohydrates of the WPCS treatment cattle were higher (p < 0.05), and the ethereal extract intake of cattle fed CSC diet was higher. The BW of cattle fed WPCS was higher in the two initial periods of confinement (p < 0.05). Animals from both treatments showed linear growth during the confinement period. There was a fiber source × period interaction for total weight gain (TWG), average daily gain (ADG) and feed efficiency (FE) (p < 0.05), with the lowest in the first 15days and the highest at 30days, reflecting a compensatory gain in animals fed with CSC. Bulls fed with CSC showed negative TWG and ADG in the first period (p < 0.05), but recovered in the following periods, surpassing that of the SC treatment in the last two periods. There was negative EF of bulls fed with CSC in the first period (P < 0.05), but in the following periods the CSC diet did not differ from the WPCS diet. The animals fed CSC diet showed a higher concentration of cholesterol and glucose in the blood plasma (p < 0.05). The forage-free diet containing cottonseed cake as a source of fiber replacing corn silage promoted better animal performance.

B-spline polynomials models for analyzing growth patterns of Guzerat young bulls in field performance tests.

The aim of this study was to identify suitable polynomial regression for modeling the average growth trajectory and to estimate the relative development of the rib eye area, scrotal circumference, and morphometric measurements of Guzerat young bulls. A total of 45 recently weaned males, aged 325.8±28.0 days and weighing 219.9±38.05 kg, were evaluated. The animals were kept on Brachiaria brizantha pastures, received multiple supplementations, and were managed under uniform conditions for 294 days, with evaluations conducted every 56 days. The average growth trajectory was adjusted using ordinary polynomials, Legendre polynomials, and quadratic B-splines. The coefficient of determination, mean absolute deviation, mean square error, the value of the restricted likelihood function, Akaike information criteria, and consistent Akaike information criteria were applied to assess the quality of the fits. For the study of allometric growth, the power model was applied. Ordinary polynomial and Legendre polynomial models of the fifth order provided the best fits. B-splines yielded the best fits in comparing models with the same number of parameters. Based on the restricted likelihood function, Akaike's information criterion, and consistent Akaike's information criterion, the B-splines model with six intervals described the growth trajectory of evaluated animals more smoothly and consistently. In the study of allometric growth, the evaluated traits exhibited negative heterogeneity (b<1) relative to the animals' weight (p<0.01), indicating the precocity of Guzerat cattle for weight gain on pasture. Complementary studies of growth trajectory and allometry can help identify when an animal's weight changes and thus assist in decision-making regarding management practices, nutritional requirements, and genetic selection strategies to optimize growth and animal performance.

Effects of Slaughter Weight and Muscle Types on Carcass and Meat Quality Characteristics of Holstein Friesian Bulls

The aim of this study was to determine the effects of slaughter weight and muscle types on carcass characteristics, chemical composition and meat quality characteristics of young Holstein Friesian bulls. For this purpose, the 21 young bulls were assigned to three experimental groups based on their weights at slaughter called lighter (LSW) (470.4±32.5kg), medium (MSW) (540.8±10.9 kg) and heavier (HSW) (605.8±28.3 kg). Animals in the HSW group resulted in higher carcass weight, LD area, crude protein content, pH24 value. On the other hand, L* and a* values color parameters and LD area per 100 kg carcass weight were significantly decreased with the increasing slaughter weight. The meat obtained from the LSW group were brighter and redder compared to other two slaughter groups. Additionally, there was a decreasing trend in the proportion of the non-carcass components with increasing of the slaughter weight. However, increasing of the slaughter weights led to a significant increase in the carcass measurements such as thoracic depth, carcass length, length of the round as well as width of the round. Although the crude protein content was significantly affected by both slaughter weights and muscle types, only muscle types were also significant sources of variation in percentages of moisture and crude ash.

Modelling the physiological, muscular, and sensory characteristics in relation to beef quality from 15 cattle breeds

Sensory beef quality is an important parameter for consumers, but it is difficult to understand what determines quality because of the large variation due to breed, type of animal, sex, and farm management. To address these challenges, meat samples from Longissimus thoracis (LT) were collected 24 h after slaughter from a total of 436 young bulls representing 15 cattle breeds. The samples were analysed for physiological, muscular, and sensory characteristics to evaluate beef quality. Ten groups of variables were identified by hierarchical cluster analysis of individual variables and Principal Component Analysis (PCA). The variables described distinct characteristics, including Physiologicaltraits (animal maturity, growth rate, muscle mass), Sensorytraits (tenderness, juiciness, flavor, meat colour), and some Muscularcharacteristics such as lipid content, maturation enzymes and oxidative metabolism, which are likely to discriminate among breeds. The analyses showed that muscular characteristics are positively associated with beef sensory characteristics whereas physiological characteristics are negatively associated with sensory quality. Dairy breeds produced beef rich in lipids with a strong flavour, French breeds showed fast growth rate and highly flavoured meat, and Italian breeds were characterised by good muscular development. In contrast, British breeds have oxidative muscles and produce beef with a strong flavour. Danish breeds have an intermediate score for the sensorial and muscular characteristics.

Perfil sérico do hormônio anti-Mülleriano de touros Nelore na peripuberdade

ABSTRACT This study aimed to investigate the profile of AMH serum concentrations during the period of prepuberty in young bulls. The bulls were selected and evaluated for 150 days to assess their sexual development. The semen and blood collection, body weight (kg), and scrotal measurements were performed every 30 days, and puberty (D0) was considered when at least 50×106 spermatozoa/mL, and 10% of progressive motility were verified for the first time. After the blood collection, plasma was separated and used to determine the AMH concentration by ELISA, presenting values of 611.4a (±94.5), 555a (±181.99), 621.6ab (±133.44), 370.4ab (±59.36) and 51.7b (±7.94) for moments of -60, -30, 0, +30 and +60 of puberty, respectively. During the evaluated period, there was a progressive increase in body weight (kg), scrotal circumference (cm), and semen characteristics. The AMH mean plasma concentration decreased 60 days after puberty onset. There was no correlation with the andrological parameters analyzed; however, there was a positive and strong correlation between the testicular height and width at puberty onset with plasma concentrations of AMH. We concluded that AMH is not a helpful tool for the early prediction of puberty in Nelore bulls.

Theileria orientalis Ikeda infection does not negatively impact growth performance or breeding soundness exam results in young beef bulls at bull test stations.

Theileria orientalis Ikeda genotype is an emerging cattle disease in the US. Since 2017, when T. orientalis Ikeda was discovered in beef cattle in two counties in Virginia, cattle infections have risen to include ~67% of Virginia counties and 14 states. Consistent with New Zealand studies, many infected herds in Virginia were >90% positive upon initial testing without overt evidence of infection. Central bull tests present a unique opportunity to study the effects of T. orientalis Ikeda infections, as bulls from multiple source herds are consolidated. The objective of this study was to determine if infection with T. orientalis Ikeda affected the average daily gain (ADG), adjusted yearling weight (AYW) and breeding soundness of bulls at two test stations in Virginia over a period of years. The bulls were fed and housed similarly to compare their growth performance and breeding soundness. For T. orientalis Ikeda testing, DNA was extracted from whole blood for quantitative polymerase chain reaction. The number of bulls infected with T. orientalis Ikeda at initial delivery to the stations increased significantly over the years studied. Multivariable linear regression models, using Angus bulls from Virginia test stations, indicated no significant effect on ADG or AYW in bulls that became test positive during the test or were positive for the duration, compared to Angus bulls that were negative for the duration. At LOC A, the odds of passing a breeding soundness exam (BSE) were not significantly different for bulls that turned positive during the test or were positive for the duration, compared to bulls that were negative for the duration of the test. At LOC B, bulls that became positive during the test were 2.4 times more likely (95% CI: 1.165-4.995, p = 0.016) to pass their BSE compared to bulls that remained negative throughout the test. We do not suppose that an obscured infection of T. orientalis Ikeda is protective for bulls to pass a BSE. However, this study demonstrates an obscured infection of T. orientalis Ikeda does not negatively affect weight gain or achievement of a satisfactory BSE rating at the central bull test stations in Virginia.

Hematological indicators of young bulls fed with genetically modified soybeans

Hematological indicators of young bulls fed with genetically modified soybeans

Natural superfetation idiopathic abortion in Pasundan cattle

Abortion in cows is a condition in which the foetus is unable to survive until it is born. This paper is the first report of a case of superfetated idiopathic abortion from natural mating that occurred in primiparous Pasundan cows. The cows were initially kept in a colony pen system and mixed between young bulls (n=10) and heifers (n = 18) for two weeks after moving the cows from the livestock pen in Ciamis Regency. Pregnancy occurs because of natural mating in heifers without a known age and pregnancy history. Two months later, a primiparous Pasundan cow was observed to show symptoms of vaginal bleeding and straining, accompanied by the expulsion of a small foetus (length ~ 25 cm, foetal age ~ 120 days) several hours later and had previously experienced an abortion with a large foetus (length ~ 36 cm, foetal age ~150 days). Primiparous Pasundan cows that experienced abortion were separated into individual pens to reduce stress and for further observation. The therapy given is antibiotics and multivitamins were administered as therapeutic agents.

EFFECTS OF THE LONG-TIME RIPENING OF BEEF UPON ITS QUALITY PARAMETERS

Subject. The subject is beef obtained from young bulls of the Aberdeen-Angus beef breed. Purpose. The purpose is to investigate the effects of dry ripening of beef upon its quality and safety parameters. Methods. The content of protein (by mass) was determined by the content of total nitrogen according to Kjeldahl followed by distillation of ammonia; the content of water (by mass) – by drying the portion to constant weight at the temperature of 105ºС; content of fat (by mass) – Soxhlet method; pH – potentiometric method; water-binding ability – by pressing the test sample; sensorial parameters – consumer assessment using a hedonic scale of 9 levels; rheological parameters – using a universal electromechanical testing machine; microbiological parameters – based on the total number of microorganisms in 1 g of product. Results. The quality parameters of long-ripened meat (within 21 days) were studied in comparison with traditionally ripened meat (within 5 days). Sensorial assessment has shown the benefits of long-ripened meat. It was found that in long-ripened beef samples the content (by mass) of protein and fat is higher by 12.97% and 21.41%, respectively; water-binding capacity is 10.69% higher. This leads to a reduction in meat moisture loss during heat treatment by 6%. It has been determined that the penetration force of long-ripened meat is less important compared to similar parameters of traditionally ripened meat. Microbiological studies have shown that meat on the 21st day of ripening corresponds to standard values. Scope of results. A technological instruction for the production of fermented meat has been developed. The developed solution was tested in industrial conditions, and a production inspection certificate was obtained.

Genotype-by-environment interactions for feed efficiency traits in Nellore cattle based on bi-trait reaction norm models

BackgroundSelecting animals for feed efficiency directly impacts the profitability of the beef cattle industry, which contributes to minimizing the environmental footprint of beef production. Genetic and environmental factors influence animal feed efficiency, leading to phenotypic variability when exposed to different environmental conditions (i.e., temperature and nutritional level). Thus, our aim was to assess potential genotype-by-environment (G × E) interactions for dry matter intake (DMI) and residual feed intake (RFI) in Nellore cattle (Bos taurus indicus) based on bi-trait reaction norm models (RN) and evaluate the genetic association between RFI and DMI across different environmental gradient (EG) levels. For this, we used phenotypic information on 12,958 animals (young bulls and heifers) for DMI and RFI recorded during 158 feed efficiency trials.ResultsThe heritability estimates for DMI and RFI across EG ranged from 0.26 to 0.54 and from 0.07 to 0.41, respectively. The average genetic correlations (± standard deviation) across EG for DMI and RFI were 0.83 ± 0.19 and 0.81 ± 0.21, respectively, with the lowest genetic correlation estimates observed between extreme EG levels (low vs. high) i.e. 0.22 for RFI and 0.26 for DMI, indicating the presence of G × E interactions. The genetic correlation between RFI and DMI across EG levels decreased as the EG became more favorable and ranged from 0.79 (lowest EG) to 0.52 (highest EG). Based on the estimated breeding values from extreme EG levels (low vs. high), we observed a moderate Spearman correlation of 0.61 (RFI) and 0.55 (DMI) and a selection coincidence of 53.3% and 40.0% for RFI and DMI, respectively.ConclusionsOur results show evidence of G × E interactions on feed efficiency traits in Nellore cattle, especially in feeding trials with an average daily gain (ADG) that is far from the expected of 1 kg/day, thus increasing reranking of animals.

Mineral composition and nutritive value of fresh and supplemented rice straws preserved in manual stacking, balling, and wrapping storage methods

Rice straws are underutilized as feed due to cattle’s preference for fresh straw. Rice straws have low nutritional value and are easily susceptible to microbial spoilage during traditional storage of loose stacking or manual open-air balling. Supplementing fresh rice straws with some minerals, energy, and protein could improve the nutritional value and storage stability under different preservation methods. The present study aimed to determine the effect of supplementing fresh rice straws with minerals, molasses, and urea, stored under three manual treatments: loose stacking, open-air balling, and airtight wrapping. Fresh rice straws were treated with 1% calcite-based mineral mixture, 0.6% molasses, and 0.05% urea and stored for 60 days. The supplemented rice straws were chopped and mixed with a basal diet composed of 55% elephant grass and 20% concentrate. Four experimental diets were then developed from the composite. That is the basal diet + fresh rice straw (FRS), basal diet+stacking supplemented rice straw (SSRS), basal diet+balling supplemented rice straw (BSSR), and basal diet+wrapping supplemented rice straw (WSRS). The experimental diets were fed to young Pesisir bulls using a 4x4 Latin Square design for eleven days. Fresh and supplemented rice straws were analyzed for dry matter, mineral content, blood hematology profile and protein content. The fresh rice straw had a relatively high potassium, iron, and manganese content but was low in calcium, sodium, phosphorus, copper, and selenium. Supplementation significantly increased the concentration of calcium, phosphorus, potassium, sodium, copper, and selenium in the preserved rice straw. Rice straw preserved in the wrapping way had the highest copper, cobalt, and selenium content. Feeding cattle with supplemented rice straw preserved in the wrapping method, decreased the blood monocyte value equivalent to that of the fresh straw. Supplementation of fresh rice straws with calcite-based minerals, molasses, and urea has the potential to increase some essential mineral content and maintained the nutritional value of rice straw preserved in an air-tied wrapping method. Key words: Calcites, Hematology, Mineral, Pesisir cattle, Rice straw, Storage, Supplementation

English

Livestock-oil palm plantations integration system is intended to improve farming efficiency, where agriculture not only plays a role as the primary producer of food but also as a producer of feed, fertilizer, energy, and other bioproducts, leading to a sustainable agricultural system. Smallholder farmers in Indonesia integrated Bali cattle and oil palm with extensive, semiintensive, and intensive management systems. This study evaluated the integrated system of oil palm and Bali cattle under different management systems regarding the characteristics of smallholder farmers, nutritional status, and weight gain of Bali cattle on smallholder farms. The study was conducted in the Regency of Central Bangka, Bangka Islands, Indonesia. The study included 108 Bali cattle grouped as calves, young, and adults. The observed variables included smallholder farmer characteristics, feed nutrients, feed nutrient consumption (Dry Matter (DM), protein, Ca, and P), feed digestibility, and body weight gain. A Randomized Block Design and analysis of variance for the obtained data were used in this experiment. Smallholder farmers implementing the integration of livestock-oil palm in Central Bangka Regency were dominated by inexperienced novice farmers. The majority of the farmer choose semi-intensive rearing management as this system produces compost as a by-product. The semi-intensive system also provides better feed quality for Bali cattle. Therefore, DM consumption in the semi-intensive system was higher than in other systems, especially in young bulls, heifers, and male and female calves (P&lt;0.05). Thus, Bali cattle in the semi-intensive system had higher average daily gain than those in the intensive or extensive system. Therefore, it can be concluded that the semi-intensive management system is the best model in the Bali cattle-oil palm integration system in the rural dryland area, in accordance with nutritional status and the characteristics of smallholder farmers in Indonesia

Genome-wide scans identify biological and metabolic pathways regulating carcass and meat quality traits in beef cattle

Genome association studies (GWAS) provides knowledge about the genetic architecture of beef-related traits that allow linking the target phenotype to genomic information aiding breeding decision. Thus, the present study aims to uncover the genetic mechanism involved in carcass (REA: rib eye area, BF: backfat thickness, and HCW: hot carcass weight) and meat quality traits (SF: shear-force, MARB: marbling score, and IMF: intramuscular fat content) in Nellore cattle. For this, 6910 young bulls with phenotypic information and 23,859 animals genotyped with 435 k markers were used to perform the weighted single-step GBLUP (WssGBLUP) approach, considering two iterations. The top 10 genomic regions explained 8.13, 11.81, and 9.58% of the additive genetic variance, harboring a total of 119, 143, and 95 positional candidate genes for REA, BF, and HCW, respectively. For meat quality traits, the top 10 windows explained a large proportion of the total genetic variance for SF (14.95%), MARB (17.56%), and IMF (21.41%) surrounding 92, 155, and 111 candidate genes, respectively. Relevant candidate genes (CAST, PLAG1, XKR4, PLAGL2, AQP3/AQP7, MYLK2, WWOX, CARTPT, and PLA2G16) are related to physiological aspects affecting growth, carcass, meat quality, feed intake, and reproductive traits by signaling pathways controlling muscle control, key signal metabolic molecules INS / IGF-1 pathway, lipid metabolism, and adipose tissue development. The GWAS results provided insights into the genetic control of the traits studied and the genes found are potential candidates to be used in the improvement of carcass and meat quality traits.

Influence of different diets and sorbents on the accumulation of Cd in the muscle tissue of young cattle and pigs

The article, based on scientific research, examines an important problematic issue regarding the quality and safety of beef and pork during their production in the Polissia zone of Ukraine, affected by the Chornobyl accident. The purpose of the research was to evaluate the effect of different diets and saponite sorbent on the level of Cd accumulation in the muscle tissue of young bulls and pigs kept in the territory belonging to the third zone of radioactive contamination. Two scientific and economic experiments were conducted. When growing Ukrainian black and white dairy young bulls, the influence of different silages (4-component cereal-bean mixture and Echinоchloa frumentаcea silage) on the content of Cd in the longest back muscle was studied (experiment 1), and optimization of the protein nutrition of animals was carried out at the expense of various feeds with a high protein content (narrow-leaved lupine and fodder beans) (experiment 2). In the third experiment, young pigs were fed various amounts of the natural mineral saponite as part of their diet, and its influence on the ecological quality of products was studied. Since different types and amounts of feed components were used when feeding the animals of the studied groups, it was necessary to balance the rations according to the content of nutrients for each of the presented groups. Regulation and verification of the nutritional value of the rationed feed was carried out monthly. When changing rations for animals, their growth, live weight, zootechnical analysis of feed, their nutritional value and feeding rates were taken into account. Sample preparation of fodder and muscles was carried out according to GSTU 7670:2014 with the help of dry mineralization, the concentration of the toxicant was determined by the atomic absorption method. The transition coefficient of Cd in the chain «diet – muscle tissue» in this study is within the established standards. At the same time, feeding by Echinоchloa frumentаcea silage contributed to a decrease in the coefficient of transition of Cd into the muscle tissue of young bulls by 0.68 % (absolute). The introduction of 30 % (by mass) of fodder beans into the grain mixture instead of a similar amount of lupine for young cattle (cattle) for fattening in the territory of radioactive contamination (the third zone) contributed to a significantly lower accumulation and transition of Cd into the muscle tissue of animals – on 25.0 % and 0.71 % (absolute), respectively. The inclusion of the natural sorbent mineral saponite in the amount of 3–7 % by mass of concentrated feed in the diet of growing and fattening pigs contributed to a reduction of Cd in the longest muscle of the back by 21.8– 37.9%, while at the same time it was better in terms of the sorption efficiency for excretion of Cd, which turned out to be a saponite dose of 7 %. Key words: young bulls, pigs, nutrition, different diets, saponite, accumulation of Cd.

PSXIV-2 Inclusion of a Slow-Release Nitrogen Ingredient Associated Or Not with Monensin on Performance, Metabolism, and Carcass Parameters of Finishing Beef Cattle Fed High Starch Diets

Abstract This study aimed to assess the effects of a slow-released nitrogen (N) ingredient in association or not with monensin on the performance, metabolism, and carcass parameters of finishing young bulls. To investigate these outcomes, 112 Nellore young bulls (380 kg ± 16.2) were used in a 2 × 2 factorial arrangement. The young bulls were allocated to 28 feedlot pens (four animals per pen) and fed a finishing high starch (51% starch) corn grain and corn silage-based diet. The following treatments were randomly assigned to the experimental units: 1) Control (CON, n = 7), finishing diet without additives; 2) Monensin-enriched diet (MON, n = 7), monensin (Rumensin, Elanco Animal Health, Greenfield, IN) provided at a level of 30 mg per kg of dry matter (DM); 3) Gradual-N-release enriched diet (SRN, n = 7), slow-N-release supplement (Timafeed Boost, Roullier Group, Saint-Malo, France) provided at a dose of 250 g per animal per day; or 4) Monensin + SRN diet (MON + SRN, n = 7), monensin (30 mg per kg of DM) associated with the SRN (250 g per animal per day). The experimental period comprised 102 days, with the first 15 days designated for diet adaptation. The average daily gain (ADG) over the experimental period was reduced for young bulls fed SRN + MON (P = 0.02) compared with those fed only SRN. Young bulls fed MON had greater DMI during the finishing phase than MON × SRN (P = 0.03). Overall, young bulls fed CON diet had greater day-by-day dry matter intake (DMI) variation than other treatments (P ≤ 0.05). The SRN inclusion in the diet improved feed efficiency by 5.7% (P = 0.04). Young bulls fed diets without SRN inclusion tended to have higher blood urea concentration (P = 0.06). Blood D-lactate and glucose levels were similar between treatments (P ≥ 0.21). The SRN use tended to increase (P = 0.09) DM digestibility (5.6% increase). The microbial crude protein was reduced by MON + SRN association (P = 0.02) compared with other treatments. The hot carcass weight was greater for the SRN group compared with MON × SRN (P = 0.02). The use of SRN in the diet increased (P ≤ 0.04) total and daily carcass gain, carcass yield, and biological efficiency. In summary, although additional studies are suggested, these data indicate that the association between SRN and monensin might require careful consideration when used in finishing diets. The SRN inclusion in finishing diets without monensin shows important potential for increasing animal performance and efficiency.

PSX-27 The Impact of Feeding Young Nellore Bulls with a Low Concentrate Diet for Different Periods Followed By a High Concentrate Diet on Dry Matter Intake and Performance

Abstract In Brazil, it is common practice to feed young bulls a low-concentrate diet (LCD) after weaning, followed by a high-concentrate diet (HCD) during the finishing phase to optimize animal growth while reducing the cost of concentrated feed. By restricting the concentrate intake during the early phase, the animals can potentially adapt better to a high-energy diet during the finishing phase, leading to improved performance. Thus, the objective of this study was to evaluate the impact of different LCD feeding periods after weaning, followed by feeding a HCD, on dry matter intake (DMI), average daily gain (ADG), feed efficiency (G:F), and final body weight (BW) of young Nellore bulls. Thirty-two young Nellore bulls (average initial BW = 265 ± 5 kg; age = 7 ± 1 mo) were used in a completely randomized design into four groups (n = 8/group) and assigned to receive one of 4 treatments containing different periods of LCD. The LCD consisted of 800 g/kg of forage sorghum silage and 200 g/kg of concentrate, while the HCD contained 200 g/kg of corn silage and 800 g/kg of concentrate. The diets were formulated according to BR-CORTE (2016) to achieve ADG of 0.6 kg/day and 1.2 kg/day for the LCD and HCD, respectively. The experiment lasted 154 days (14 days for adaptation to the HCD). The LCD and HCD feeding periods respectively were 0 and 140 (T0), 28 and 112 (T28), 56 and 84 (T56), and 84 and 56 (T84) days. All animals were fed ad libitum in an electronic feeder (INTERGADO, Intergado Ltd., Contagem, MG, Brazil), and individual daily feed intake was recorded. The bulls were weighed at the beginning and the end of the LCD and HCD feeding periods after undergoing 16 h of fasting to measure BW and ADG of both periods. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) assuming the significance level of 0.05. There was no evidence that different LCD feeding periods impacted DMI (P = 0.99), ADG (P = 0.59), or G:F (P = 0.48) during the LCD feeding period. The DMI during the HCD feeding period of T0 did not differ from the others, the T28 was not significantly different from the T84, and the T56 treatment was greater than T28 and T84 (P &amp;lt; 0.05). No significant difference was found between the treatments for ADG (P = 0.09) and G:F (P = 0.98) during the HCD feeding period. The T0 had the heaviest final BW, while there was no difference between the T28 and T56 groups, and the T84 group had the lightest final BW(P &amp;lt; 0.01). Given that the final BW was heavier for T0, it may be inferred that there are no benefits to using LCD feeding periods.