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Background: The level of accumulated caloric load of the ITH (CCA) during the 6 months prior to weaning on the weaning weight (PD) was evaluated in Charolais animals as an expression of thermal stress (ST), as well as its possible genetic component. Methods: 19,466 PD records from the Manuel Fajardo Enterprise, Jiguaní, Granma, born between 1988 and 2017 in 16 herds, were analyzed. A Reaction Norm model was used considering a fixed effect of quarters-years-herds (859 classes), sex of the calf (2) and number of calving of the mother (11), a fixed covariate using a Legendre polynomial (L) of order 3 to represent the PD response curve in the CCA trajectory. As random: residual and the deviation of the animal that produces the record that was modeled by an L of order 1. With the standardized genetic values (VG) a principal components analysis was done and with the eigenvector coefficients an index of the results. Results: The regression analysis showed that PD is depressed by b=-0,807±0,04 kg per unit of CCA (R²=90,2%). 3 zones were differentiated: cold CCA<=439; neutral CCA>=440 to <=450 and hot CCA>=451, with PD= 149,3; 140,5 and 134,1 kg respectively. The variation in VG is greater in the cold zone, but the correlations were very low (0,33), evidencing genotype-environment interaction (Ige). Conclusions: The existence of a genetic basis for tolerance to ST with Ige manifestations was demonstrated, and the order of merit changes in extreme conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: Predicted breeding values significantly influence the selection of suitable individuals for further breeding. For traits with low heritability, including fertility, the reliability of breeding value tends to be low, and it increases gradually with increasing performance records and offspring. A large number of beef cattle are raised extensively, where they are grazed on pasturelands, but this system provides only limited opportunities for data collection. Incorporating genomic information for individuals leads to an increase in the reliability of the predicted genomic breeding value. However, the increase in reliability is not uniform among individuals, and it varies among breeding groups within a breed. In our study, the benefit was observed for all genotyped individuals, especially in young individuals of both sexes. No significant increase in the reliability of genomic breeding values was observed for nongenotyped individuals; however, this trend may change as the number of individuals in the population are genotyped. The aim of this study was to assess the impact of incorporating genomic data using the single-step genomic best linear unbiased prediction (ssGBLUP) method compared to the best linear unbiased prediction (BLUP) method on the reliability of breeding values for age at first calving, calving interval, and productive longevity at 78 months in Charolais cattle. The study included 48,590 purebred Charolais individuals classified into four subgroups based on genotyping and performance records. The results showed that considering genotypes significantly improved genomic estimated breeding values (GEBV) reliability across all categories except nongenotyped individuals. For young genotyped individuals, the increase in reliability was up to 27% for both sexes. The highest average reliability was achieved for genotyped proven bulls and cows with performance records, and the inclusion of genomic data further improved the reliability by up to 22% and 21% for cows and bulls, respectively. The gain in reliability was observed mainly during the first three calvings, and then the differences decreased. The imported individuals showed lower estimated breeding values (EBV) and GEBV reliabilities than the domestic population, probably due to the weak genetic connection with the domestic population. However, when the progeny of imported heifers were sired by domestic bulls, the reliability increased by up to 24%. For nongenotyped individuals, only a slight increase in reliability was observed; however, the number of genotyped individuals in the population was still relatively small. [ABSTRACT FROM AUTHOR]

Antecedentes: El nivel de carga calórica acumulada del ITH (CCA) durante los 6 meses previos al destete sobre el peso al destete (PD), fue evaluado en animales Charoláis como expresión de stress térmico (ST), así como su posible componente genético. Métodos: Se analizaron 19 466 registros de PD de la Empresa Manuel Fajardo, Jiguaní, Granma, nacidos entre 1988 y 2017 en 16 rebaños. Se utilizó un modelo de Norma de Reacción considerando efecto fijo cuatrimestres-años-rebaños (859 clases), sexo del ternero (2) y número de partos de la madre (11), una covariable fija mediante un polinomio de Legendre (L) de orden 3 para representar la curva de respuesta del PD en la trayectoria de CCA. Como aleatorios: residuo y la desviación del animal que produce el registro que se modeló por un L de orden 1. Con los valores genéticos estandarizados (VG) se hizo un análisis de componentes principales y con los coeficientes de los eigenvector se construyó un índice de los resultados. Resultados: El análisis de regresión arrojó que el PD se deprime en b=-0,807±0,04 kg por unidad de CCA (R2=90,2%). Se diferenciaron tres zonas: fría CCA=440 a =451, con PD= 149,3; 140,5 y 134,1 kg respectivamente. La variación en VG es mayor en la zona fría, pero las correlaciones fueron muy bajas (0,33) evidenciando interacción genotipo ambiente (Ige). Conclusiones: Se demostró existencia de una base genética para tolerancia a ST con manifestaciones de Ige, y cambia el orden de mérito en condiciones extremas.

Se estimó la exactitud de la predicción (EP) de valores genómicos estimados (GEBV) para variables de peso vivo de ganado Charolais utilizando dos métodos de validación cruzada. Se ajustó un modelo BLUP y diferentes métodos de predicción genómica (PG) Genomic-based best linear unbiased prediction (GBLUP), Bayes C (BC) y Single-step Bayesian regression (SSBR). La EP fue comparada mediante grupos de validación (GV) formados aleatoriamente y mediante GC. Los resultados mostraron que los tres métodos de PG proporcionaron exactitudes de predicción similares entre los GV pero no exactitudes de predicción superiores a BLUP. La exactitud de predicción de GBLUP y BLUP fue 0.35 y 0.37 para PN, y de 0.30 y 0.41 para PD, respectivamente. Los resultados muestran bajas exactitudes de PG bajo los escenarios evaluados; por lo que para su correcta implementación es necesario incrementar el número de animales y usar valorees genéticos desregresados como variables de respuesta.

Simple Summary: Meat producers are trying to increase the efficiency of beef production, with a primary focus on genetic and management strategies for beef cattle breeding. Calf birth weight and growth potential, such as weight at different growth periods, are influenced by a variety of genetic and non-genetic factors. The objective of this study was to evaluate the impact of cows' calving age and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The gender of the calf, cows' age at first calving, cows' number of calvings, and the breeding and calving seasons are frequently used indicators in beef cattle farming. According to the influence of selected factors in this study, it can be concluded that the body weight and growth rates of newborn calves are significantly influenced by the gender of the calf, the number of calvings, as well as calving and breeding seasons, should be taken into account in future animal breeding studies. The objective of this study was to evaluate the impact of cows' calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p < 0.05). The gender of the calves affected their weight, indicating that newborns bulls were significantly heavier. Calf gender affected calf growing performance. Male calves' weight gain was higher than that of females in the time before weaning (210 days). The highest gain of bulls was observed from 211 days to 365 days after birth. The average daily weight of male calves during this period was 6.16% (p < 0.001) higher compared to the period up to 210 days after birth. Heifers had a higher daily weight in the period up to 210 days after birth, and the daily weight gain was 12.9% (p < 0.001) higher in this period compared to the period from 211 to 365 days after birth. We observed a higher weight gain in calves from mothers with a higher number of calvings. Being born from cows with four or more calvings had a significant effect on the weight gain of calves in the period up to 210 days (p < 0.05). In the period up to 210 days, the weight gain of calves born from cows with two calvings was the lowest and was 9.79% lower compared to calves born from cows with four and more calvings (p < 0.05). The best weights were obtained from calves born in the spring and autumn seasons. Calves born in spring, summer, and autumn differed in weight by 0.37 kg. The calves of cows that were inseminated in the autumn season had the highest gain in the period up to 210 days and also from 210 to 365 days (p < 0.05). In our study, significantly higher average birth weight of calves was detected in autumn compared to summer and winter (p < 0.05). Also, the highest gain was found from 211 to 365 days after birth in the summer season, but the difference was only 1.47% (p < 0.05). [ABSTRACT FROM AUTHOR]

The misuse of antibiotics in the animal sector is the main driver of antibiotic resistance. More than 80% of Italian beef cattle imported from France are Charolais, which undergo a commingling procedure before reaching Italian fattening farms. The aim of this study was to evaluate the effect of commingling Charolais cattle in France on antibiotic use (AMU) and animals’ performances in Italy. A total of 19,756 young bulls from 449 batches transported to Italy between 2016 and 2018 were considered. Carcase weight (CW), slaughter age (SA), antibiotic treatments, vaccinations information and the French department of origin were available for each animal. Also, treatment incidence 100 (TI100it) and average daily carcase gain (ADCG) were calculated. Three classes of commingling were assigned to each animal according to the French department of origin. A linear mixed model was used to investigate sources of variation of CW, SA, ADCG and TI100it. Respiratory diseases were the main reasons for treatment and macrolides were the most used class of antibiotics. The TI100it decreased by 11% from 2016 to 2018 (p < .05). Animals that went through the highest level of commingling had lighter CW, lower ADCG and greater TI100it than animals subjected to lower commingling (p < .05). Younger animals reached higher TI100it than older ones (p < .05). Younger and highly commingled animals had higher TI100it (p < .001) than older animals equally commingled. This first-of-its-kind study showed that commingling procedures increase the risk of AMU and affect the performances of Charolais cattle.HIGHLIGHTS Commingling procedures increase the use of antibiotics and penalise animals’ performances. Younger and highly commingled animals are at greater risk of being treated. Reducing commingling levels can be an effective strategy to reduce antibiotic use in beef cattle.

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.

The evaluation of genetic diversity and gene flow through genealogical information of a population is necessary in genetic selection programs. Therefore, the objective of the study was to evaluate the diversity and genetic structure of the Charolais population in Ecuador. Three sets of data were used, the historical population, current population and the reference population. The information on each animal included its own name and registration number, that of the father, the mother, and date of birth. The parameters evaluated were the completeness of the pedigree, generation interval, inbreeding, mean relationship, increase in inbreeding and effective population size. For data processing, the ENDOG program was used. The completeness of the pedigree decreased considerably from the second generation in both populations, although the first generation showed values of 0.617 and 0.745. The average generation interval was 7.17 years for the historical population and 8.42 years for the current one. The father pathway was superior to the maternal pathway in both populations. Inbreeding values were 0.08% and 0.14%, respectively. The Ne was 537.38. The Charolais cattle breed in Ecuador is in the process of being established, and can be considered a young population from the genetic point of view. The use of reproductive biotechnologies with molecular information has directly influenced the quality of the genealogical information added to the control in the records of new animals, which will allow the association to have reliable tools for population management. [ABSTRACT FROM AUTHOR]

The misuse of antibiotics in the animal sector is the main driver of antibiotic resistance. More than 80% of Italian beef cattle imported from France are Charolais, which undergo a commingling procedure before reaching Italian fattening farms. The aim of this study was to evaluate the effect of commingling Charolais cattle in France on antibiotic use (AMU) and animals' performances in Italy. A total of 19,756 young bulls from 449 batches transported to Italy between 2016 and 2018 were considered. Carcase weight (CW), slaughter age (SA), antibiotic treatments, vaccinations information and the French department of origin were available for each animal. Also, treatment incidence 100 (TI100it) and average daily carcase gain (ADCG) were calculated. Three classes of commingling were assigned to each animal according to the French department of origin. A linear mixed model was used to investigate sources of variation of CW, SA, ADCG and TI100it. Respiratory diseases were the main reasons for treatment and macrolides were the most used class of antibiotics. The TI100it decreased by 11% from 2016 to 2018 (p <.05). Animals that went through the highest level of commingling had lighter CW, lower ADCG and greater TI100it than animals subjected to lower commingling (p <.05). Younger animals reached higher TI100it than older ones (p <.05). Younger and highly commingled animals had higher TI100it (p <.001) than older animals equally commingled. This first-of-its-kind study showed that commingling procedures increase the risk of AMU and affect the performances of Charolais cattle. Commingling procedures increase the use of antibiotics and penalise animals' performances. Younger and highly commingled animals are at greater risk of being treated. Reducing commingling levels can be an effective strategy to reduce antibiotic use in beef cattle. [ABSTRACT FROM AUTHOR]

The European carcass grading scheme (EUROP) places large emphasis on meat yield and therefore on quantitative traits such as carcass conformation and superficial fat coverage. However, it falls short in considering sensory properties and consumer satisfaction. In contrast, the Meat Standards Australia (MSA) grading scheme considers, among others, animals' ossification, marbling, and ultimate pH as primary indicators of beef eating quality. This study aims to characterize MSA carcass grading scheme applied to the Italian beef production system, considering its significant role in European beef market. The study involved 3204 Charolais, Limousin, and crossbred young bulls and heifers slaughtered in a commercial Italian abattoir. Data collection spanned a broad range of variables, including animal characteristics, MSA traits, and EUROP carcass grading traits. Regardless of the sex of the animal, no significant relationship was observed between MSA traits and EUROP carcass grading scores. Factors such as sex, age, and arrival season at the fattening unit significantly affected most of MSA traits. Females had significantly higher marbling score, and lower ossification score and hump height than males. Animals imported in autumn and winter had significantly lower marbling score, but similar ossification score compared to those imported in spring and summer. Older females had the highest marbling scores. While further research is needed to assess whether the MSA grading scheme can be adapted to all different European rearing systems, results of this study are a prelude to the potential benefits that the MSA grading scheme can bring to the European beef industry. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the impact of cows’ calving ages and newborn calf body weight on the pre-weaning growth rates of calves under the farming conditions of a northeastern European country. The females were purebred Charolais cows that calved between 2019 and 2022. A total of 130 calves (bulls = 76; heifers = 54) were observed during the evaluation. The investigation showed that, based on gender, bulls had a 4.28% higher birth weight than heifers (p < 0.05). The gender of the calves affected their weight, indicating that newborns bulls were significantly heavier. Calf gender affected calf growing performance. Male calves’ weight gain was higher than that of females in the time before weaning (210 days). The highest gain of bulls was observed from 211 days to 365 days after birth. The average daily weight of male calves during this period was 6.16% (p < 0.001) higher compared to the period up to 210 days after birth. Heifers had a higher daily weight in the period up to 210 days after birth, and the daily weight gain was 12.9% (p < 0.001) higher in this period compared to the period from 211 to 365 days after birth. We observed a higher weight gain in calves from mothers with a higher number of calvings. Being born from cows with four or more calvings had a significant effect on the weight gain of calves in the period up to 210 days (p < 0.05). In the period up to 210 days, the weight gain of calves born from cows with two calvings was the lowest and was 9.79% lower compared to calves born from cows with four and more calvings (p < 0.05). The best weights were obtained from calves born in the spring and autumn seasons. Calves born in spring, summer, and autumn differed in weight by 0.37 kg. The calves of cows that were inseminated in the autumn season had the highest gain in the period up to 210 days and also from 210 to 365 days (p < 0.05). In our study, significantly higher average birth weight of calves was detected in autumn compared to summer and winter (p < 0.05). Also, the highest gain was found from 211 to 365 days after birth in the summer season, but the difference was only 1.47% (p < 0.05).

The objective of this study was to estimate economic returns and costs associated with 4 scenarios of genetic evaluation that combine genotypes, phenotypes, and pedigree information from a vertically integrated purebred (PB) and commercial (CM) beef cattle system. Inference was to a genetic evaluation for a production system producing Charolais terminal sires for 10,000 CM cows. The first genetic evaluation scenario, denoted PB_A, modeled a genetic evaluation in which pedigree information and phenotypes are available for PB seedstock animals. Scenario PB_H contained the same information as PB_A with the addition of 25K density (GeneSeek Genomic Profiler LD) single nucleotide polymorphism (SNP) genotypes from PB animals. Scenario PBCM_A contained pedigree records and phenotypes from PB and CM cattle. Scenario PBCM_H contained phenotypes, pedigree, and genotypes from the PB and CM animals. Estimates of prediction error variance, (co)variance, and selection index parameters were used to estimate accuracy of selection candidates (rTI) and genetic gain resulting from selection on an economic index in US dollars (ΔG). Annual costs and incomes were used to determine the 30-yr cumulative net present value (CNPV) per CM calf resulting from selection in these genetic evaluation scenarios. Adding genotypes and CM production phenotypes to genetic evaluation increased the rTI of selection candidates and ΔG across all 4 scenarios. Scenario PBCM_H produced the highest annual ΔG in the PB herd at US$11.91 per head. Including CM phenotypes and parentage testing in the genetic evaluation increased the time to breakeven from 12 yr in PB_A to 19 years in PBCM_A after accounting for the cost of that information. Adding CM phenotypes and genotypes increased the breakeven time from 12 yr in PB_H to 18 yr in PBCM_H. Scenario PB_H produced the highest 30-yr CNPV per slaughtered CM calf at US$371.16. These results using field data indicate that economically relevant rTI and ΔG can be realized by adding 25K SNP genotypes and CM phenotypes to genetic evaluation, but the additional cost of that data significantly delays the economic return to the enterprise.

Abstract Background The carcass value of cattle is a function of carcass weight and quality. Given the economic importance of carcass merit to producers, it is routinely included in beef breeding objectives. A detailed understanding of the genetic variants that contribute to carcass merit is useful to maximize the efficiency of breeding for improved carcass merit. The objectives of the present study were two-fold: firstly, to perform genome-wide association analyses of carcass weight, carcass conformation, and carcass fat using copy number variant (CNV) data in a population of 923 Holstein-Friesian, 945 Charolais, and 974 Limousin bulls; and secondly to perform separate association analyses of carcass traits on the same population of cattle using the Log R ratio (LRR) values of 712,555 single nucleotide polymorphisms (SNPs). The LRR value of a SNP is a measure of the signal intensity of the SNP generated during the genotyping process. Results A total of 13,969, 3,954, and 2,805 detected CNVs were tested for association with the three carcass traits for the Holstein-Friesian, Charolais, and Limousin, respectively. The copy number of 16 CNVs and the LRR of 34 SNPs were associated with at least one of the three carcass traits in at least one of the three cattle breeds. With the exception of three SNPs, none of the quantitative trait loci detected in the CNV association analyses or the SNP LRR association analyses were also detected using traditional association analyses based on SNP allele counts. Many of the CNVs and SNPs associated with the carcass traits were located near genes related to the structure and function of the spliceosome and the ribosome; in particular, U6 which encodes a spliceosomal subunit and 5S rRNA which encodes a ribosomal subunit. Conclusions The present study demonstrates that CNV data and SNP LRR data can be used to detect genomic regions associated with carcass traits in cattle providing information on quantitative trait loci over and above those detected using just SNP allele counts, as is the approach typically employed in genome-wide association analyses.

The issue was solved by the growth of 632 Charolais calves born between 2011 and 2016 from three farms in the Slovak Republic who are part of performance beef cattle testing. In our work was evaluated a live birth weight, weight at 120 days of age, weight at 210 days of age, weight at age 365 days, average daily gain from birth to 120 days of age, average daily gain between 120 and 210 days of age and average daily gain up to 365 days. Assessment factors were selected by breeder, sex of calves, calf birth year, calf birth month and sire effect. Evaluating of the live weight at birth founded the highest weight of farm A (42.92 kg), which is closest to the breed standard. Heaviest calves were born in 2016 with very high significant effect (p0.05).

The issue was solved by the growth of 632 Charolais calves born between 2011 and 2016 from three farms in the Slovak Republic who are part of performance beef cattle testing. In our work was evaluated a live birth weight, weight at 120 days of age, weight at 210 days of age, weight at age 365 days, average daily gain from birth to 120 days of age, average daily gain between 120 and 210 days of age and average daily gain up to 365 days. Assessment factors were selected by breeder, sex of calves, calf birth year, calf birth month and sire effect. Evaluating of the live weight at birth founded the highest weight of farm A (42.92 kg), which is closest to the breed standard. Heaviest calves were born in 2016 with very high significant effect (p<0.001) on the birth weight. Male calves were heavier than heifers in single, heifer twins were also heavier. High statistical significance (p<0.001) was detected by sire. In our work we've founded the best weaning weight 229.11 kg in lower birth weight (33.52 kg). This indicator reduced over the years up to year 2016, when the weight raised again. Heifers reached higher values than bulls (203.74 kg compared to 177.40 kg), while the impact of this factor was statistically significant (p<0.05). The highest calves weaning weight was found in the October (224.35 kg) and the January (209.98 kg). We also investigated the correlation dependence of growth characteristics, when we found a positive correlation dependence (r = 0.03) between weaning weight and birth weight, which is statistically not significant (p>0.05). [ABSTRACT FROM AUTHOR]

This study aims to describe the meat quality of young Holstein (HOL) beef-on-dairy heifers and bulls sired by Angus (ANG, n = 109), Charolais (CHA, n = 101) and Danish Blue (DBL, n = 127), and to investigate the performance of the handheld vision-based Q-FOM™ Beef camera in predicting the intramuscular fat concentration (IMF%) in M. longissimus thoracis from carcasses quartered at the 5th–6th thoracic vertebra. The results showed significant differences between crossbreeds and sexes on carcass characteristics and meat quality. DBL × HOL had the highest EUROP conformation scores, whereas ANG × HOL had darker meat with higher IMF% (3.52%) compared to CHA × HOL (2.99%) and DBL × HOL (2.51%). Bulls had higher EUROP conformation scores than heifers, and heifers had higher IMF% (3.70%) than bulls (2.31%). These findings indicate the potential for producing high-quality meat from beef-on-dairy heifers and ANG bulls. The IMF% prediction model for Q-FOM performed well with R2 = 0.91 and root mean squared error of cross validation, RMSECV = 1.33%. The performance of the prediction model on the beef-on-dairy veal subsample ranging from 0.9 to 7.4% IMF had lower accuracy (R2 = 0.48) and the prediction error (RMSE veal) was 1.00%. When grouping beef-on-dairy veal carcasses into three IMF% classes (2.5% IMF bins), 62.6% of the carcasses were accurately predicted. Furthermore, Q-FOM IMF% predictions and chemically determined IMF% were similar for each combination of sex and crossbreed, revealing a potential of Q-FOM IMF% predictions to be used in breeding, when aiming for higher meat quality. • Intramuscular fat was highest in Angus, then Charolais, then Danish Blue crossbreeds. • Crossbred heifers had more intramuscular fat than bulls at 10 months age. • Q-FOM™ Beef can predict eye muscle intramuscular fat at 5th–6th thoracic vertebra. • Q-FOM™ Beef can be a tool in breeding for higher meat quality in beef-on-dairy. [ABSTRACT FROM AUTHOR]

The relative contributions of both copy number variants (CNVs) and single nucleotide polymorphisms (SNPs) to the additive genetic variance of carcass traits in cattle is not well understood. A detailed understanding of the relative importance of CNVs in cattle may have implications for study design of both genomic predictions and genome-wide association studies. The first objective of the present study was to quantify the relative contributions of CNV data and SNP genotype data to the additive genetic variance of carcass weight, fat, and conformation for 945 Charolais, 923 Holstein-Friesian, and 974 Limousin sires. The second objective was to jointly consider SNP and CNV data in a least absolute selection and shrinkage operator (LASSO) regression model to identify genomic regions associated with carcass weight, fat, and conformation within each of the three breeds separately. A genomic relationship matrix (GRM) based on just CNV data did not capture any variance in the three carcass traits when jointly evaluated with a SNP-derived GRM. In the LASSO regression analysis, a total of 987 SNPs and 18 CNVs were associated with at least one of the three carcass traits in at least one of the three breeds. The quantitative trait loci (QTLs) corresponding to the associated SNPs and CNVs overlapped with several candidate genes including previously reported candidate genes such as MSTN and RSAD2, and several potential novel candidate genes such as ACTN2 and THOC1. The results of the LASSO regression analysis demonstrated that CNVs can be used to detect associations with carcass traits which were not detected using the set of SNPs available in the present study. Therefore, the CNVs and SNPs available in the present study were not redundant forms of genomic data. [ABSTRACT FROM AUTHOR]

The relative contributions of both copy number variants (CNVs) and single nucleotide polymorphisms (SNPs) to the additive genetic variance of carcass traits in cattle is not well understood. A detailed understanding of the relative importance of CNVs in cattle may have implications for study design of both genomic predictions and genome-wide association studies. The first objective of the present study was to quantify the relative contributions of CNV data and SNP genotype data to the additive genetic variance of carcass weight, fat, and conformation for 945 Charolais, 923 Holstein-Friesian, and 974 Limousin sires. The second objective was to jointly consider SNP and CNV data in a least absolute selection and shrinkage operator (LASSO) regression model to identify genomic regions associated with carcass weight, fat, and conformation within each of the three breeds separately. A genomic relationship matrix (GRM) based on just CNV data did not capture any variance in the three carcass traits when jointly evaluated with a SNP-derived GRM. In the LASSO regression analysis, a total of 987 SNPs and 18 CNVs were associated with at least one of the three carcass traits in at least one of the three breeds. The quantitative trait loci (QTLs) corresponding to the associated SNPs and CNVs overlapped with several candidate genes including previously reported candidate genes such as MSTN and RSAD2, and several potential novel candidate genes such as ACTN2 and THOC1. The results of the LASSO regression analysis demonstrated that CNVs can be used to detect associations with carcass traits which were not detected using the set of SNPs available in the present study. Therefore, the CNVs and SNPs available in the present study were not redundant forms of genomic data.

Background: The carcass value of cattle is a function of carcass weight and quality. Given the economic importance of carcass merit to producers, it is routinely included in beef breeding objectives. A detailed understanding of the genetic variants that contribute to carcass merit is useful to maximize the efficiency of breeding for improved carcass merit. The objectives of the present study were two-fold: firstly, to perform genome-wide association analyses of carcass weight, carcass conformation, and carcass fat using copy number variant (CNV) data in a population of 923 Holstein-Friesian, 945 Charolais, and 974 Limousin bulls; and secondly to perform separate association analyses of carcass traits on the same population of cattle using the Log R ratio (LRR) values of 712,555 single nucleotide polymorphisms (SNPs). The LRR value of a SNP is a measure of the signal intensity of the SNP generated during the genotyping process. Results: A total of 13,969, 3,954, and 2,805 detected CNVs were tested for association with the three carcass traits for the Holstein-Friesian, Charolais, and Limousin, respectively. The copy number of 16 CNVs and the LRR of 34 SNPs were associated with at least one of the three carcass traits in at least one of the three cattle breeds. With the exception of three SNPs, none of the quantitative trait loci detected in the CNV association analyses or the SNP LRR association analyses were also detected using traditional association analyses based on SNP allele counts. Many of the CNVs and SNPs associated with the carcass traits were located near genes related to the structure and function of the spliceosome and the ribosome; in particular, U6 which encodes a spliceosomal subunit and 5S rRNA which encodes a ribosomal subunit. Conclusions: The present study demonstrates that CNV data and SNP LRR data can be used to detect genomic regions associated with carcass traits in cattle providing information on quantitative trait loci over and above those detected using just SNP allele counts, as is the approach typically employed in genome-wide association analyses. [ABSTRACT FROM AUTHOR]

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• Heterosis manifests itself in behavioral characteristics. • There is improvement in the behavior of beef cattle in confinement. • Behavioral evaluations show inverse results for bos taurus and bos indicus. • Bos taurus has a whirlpool location compatible with calmer animals than bos indicus. • Heterosis for behavioral traits accompanies heterozygosity in generations of crosses between bos taurus and bos indicus. Crossbreeding is one way of achieving complementarity between breeds in relation to economically important characteristics; in addition, it allows the effect of heterosis to be exploited. The aim of this study was to measure the behavioural evolution of different genetic groups and mating systems in continuous alternating crosses of Charolais and Nellore cattle. Seventy-nine purebred Charolais (C) and Nellore (N) steers were evaluated during finishing in confinement, together with their second (3/4C 1/4 N and 3/4 N 1/4C), third (5/8C 3/8 N and 5/8 N 3/8C) and fourth generation (11/16C 5/16 N and 11/16 N 5/16C) crosses. The confinement period was 97 days, including 13 days for adaptation to the environment and feeding regime. Behavioural assessments were carried out when weighing, evaluating the composite scale score, time taken to exit the scales, measurement of flight distance, location of the facial hair whorl, and plasma cortisol level at slaughter. The Charolais animals showed a better composite scale score, longer exit time and shorter flight distance than the Nellore animals. For generation 3 (5/8 animals), the inclusion of Charolais genes afforded a higher composite scale score in each of the assessments, longer flight time in the assessments at 14 and 77 days, shorter flight distance in each of the assessments, with the facial hair whorl positioned further below the eye line, determining animals of a calmer behaviour. Purebred Nellore and predominantly Nellore animals from the third generation of crosses were higher in cortisol at slaughter than the purebred Charolais or predominantly Charolais animals, showing significant heterosis only in the second generation. Bos taurus animals are calmer and have a more suitable temperament than Bos indicus , however, the behaviour of zebu cattle can improve as the period of confinement increases, with the type of handling affecting behaviour and reactivity throughout the assessments. [ABSTRACT FROM AUTHOR]

L’étude a eu pour objectif d’évaluer l’efficacité d’un traitement combiné à base de progestérone intravaginale sur l’induction de l’oestrus de femelles croisées au Cameroun. Un total de 116 vaches Goudali (Bos indicus) x Charolaises (Bos taurus) ayant mis bas au moins une fois, sans antécédent pathologique, avec une note d’état corporel supérieure à 2, ont été sélectionnées dans des élevages du département de la Vina (arrondissement de Nyambaka). Elles ont été rassemblées dans un ranch et réparties en lots de 10 animaux. Le protocole d’induction et de synchronisation des chaleurs a consisté en la pose d’un dispositif intravaginal à base de progestérone (Prid Delta) pendant huit à neuf jours. Vingt-quatre heures avant son retrait, une injection de cinq millilitres de prostaglandine F2alpha (Dinoprost, Enzaprost) a été administrée. Au moment du retrait, 500 UI de gonadotropine chorionique équine ont été injectées. Cinquante-six heures après le retrait, l’insémination a été effectuée à heure fixe avec de la semence de taureaux Gyr et Brahman. Les taux d’induction de l’oestrus et de synchronisation, de rétention du dispositif intravaginal, de gravidité en première insémination, de fécondité, et d’avortement ont été respectivement de 100 %, 100 %, 56,0 %, 51,7 %, et 4,3 % (en % des vaches traitées). Le Prid Delta s’est révélé efficace pour l’induction des chaleurs et l’obtention de gravidités chez les vaches Goudali x Charolaises.

Various floor systems are used in cattle housing with different characteristics in terms of roughness, abrasion, wetness, bedding material, ease of cleaning, etc. Thus, the activity and welfare of the animals are greatly influenced by the type of floor. The floor of the barn can influence the development of health diseases, technopathies and the production and quality of animal products. Therefore, in the present case study, we studied the effects of two different flooring systems on the performance and on some behavioral and cleanliness parameters in heifers. Two floor systems (concrete slatted flooring (CSF) and high welfare flooring (HWF)) and two breeds (Charolais and Limousin) were used in the experiment. Heifers on HWF tended to show a higher frequency of grooming, rubbing and aggression than those on CSF, but not of standing, lying, eating, drinking, rumination, resting, stereotypies and covering of the animals. In addition, animals housed on HWF also appeared to show higher cleanliness than those housed on CSF. Results indicated that animals housed on HWF exhibited more social and self-care behaviors, suggesting that animals housed on such floors show more species-specific behaviors and have higher welfare.

The aim of this study was to evaluate the effects of various dietary energy levels on the carcass and meat characteristics of feedlot-finished steers. A total of 27 purebred and crossbred Charolais and Nellore steers were used, with a mean initial age of 22 months and weight of 253 kg. The animals were allotted to a completely randomized design with three treatments and nine replicates each. Dietary treatments were arranged so that the average forage to concentrate ratio (FCR) was equivalent to that of a constant FCR treatment. The treatments consisted of CT (constant FCR at 60 to 40), CT5 (starting with 70: 30 FCR and finishing with 50: 50 FCR, that is, a mean overall FCR of 60: 40), and CT10 (starting with 80: 20 FCR and finishing with 40: 60, that is, a mean overall FCR of 60: 40). The dietary treatments did not affect slaughter weight, carcass weight, carcass conformation, physiological maturity, subcutaneous fat thickness, ribeye area, marbling score, and carcass measurements or the yield of commercial cuts. Chilling loss was higher in CT10 steers (2.41%) than in CT (2.26%) and CT5 (2.15%). [ABSTRACT FROM AUTHOR]

El objetivo fue comparar los efectos de una metodología para la clasificación de épocas climáticas, que tradicionalmente son utilizadas para establecer épocas de nacimiento (EN) en estudios y experimentos estadísticos. Esta metodología se basa en un índice de aridez (IA) para clasificar las EN utilizando información meteorológica histórica. Se trabajó una base de datos con un pedigrí de 7,460 animales, se ajustaron dos modelos para peso al nacimiento y peso al destete en bovinos Charolais manejados en pastoreo extensivo. Los modelos incluyeron el efecto fijo de grupo contemporáneo (GC= subclase de hato, sexo, año y EN) y edad de la madre. Los mismos modelos se compararon utilizando una clasificación tradicional de estaciones del año para clasificar las EN. Al estimar los componentes de varianza y valores genéticos (DEP) con sus exactitudes, los modelos fueron diferentes de acuerdo a la prueba de razón de verosimilitudes (P

The age-related carcass-morphology and composition changes and the growth and development patterns of the axial and peripheral skeleton systems and the bones composing them in the Simmental and crossbred young beef bulls have been studied. In order to carry out the survey, the young bulls were divided into three groups of 15 animals each. The first (control) group included the purebred Simmental young bulls. The second (experimental) group was formed of the halfbred and crossbred young stock produced by crossbreeding between the Simmental cows and the Simmental beef bulls of German selection. The third (experimental) group was composed of the crosses of Simmental cows with Charolais bulls. The Charolais crosses had more energy for growth. Thus, their liveweights comprised 431.9, 523.4, and 620.6 kg at the ages of 12, 15, and 18 months, respectively, which were 7.8, 7.5, and 10.2% more than that in their peers of the maternal breed. The crossbred young stock in both groups was distinct for carcass morphology and composition, reaching a more advanced level of the carcass flesh-coverage mass in all the age intervals when compared that to the purebred Simmentals. The age-related changes in the absolute and relative masses of the young-bull carcass bones are caused by different intensities specific to bone growth in the axial and peripheral skeleton systems. For instance, the intensity of bone growth in the axial skeleton system tended to increase in the postnatal period, while the bone growth rates of the peripheral skeleton system decreased. Irregularity in developing the indicated skeleton systems is caused by different intensities specific to growth of certain bones and their complexes. The highest growth rate is usually typical for ribs and the vertebral column, while the slowest growth rate is most common for extremitas thoracica and extremas pelvina. The bone growth rates for the limb proximal structures generally exceed that for the distal bone structures. The age-related differences in the growth rates of certain skeleton structures can cause some changes in ratios between the linear body measurements of the young bulls. [ABSTRACT FROM AUTHOR]

Charolais cattle are one of the most important breeds for meat production worldwide; in México, its selection is mainly made by live weight traits. One strategy for mapping important genomic regions that might influence productive traits is the identification of signatures of selection. This type of genomic features contains loci with extended linkage disequilibrium (LD) and homozygosity patterns that are commonly associated with sites of quantitative trait locus (QTL). Therefore, the objective of this study was to identify the signatures of selection in Charolais cattle genotyped with the GeneSeek Genomic Profiler Bovine HD panel consisting of 77 K single nucleotide polymorphisms (SNPs). A total 61,311 SNPs and 819 samples were used for the analysis. Identification of signatures of selection was carried out using the integrated haplotype score (iHS) methodology implemented in the rehh R package. The top ten SNPs with the highest piHS values were located on BTA 4, 5, 6 and 14. By identifying markers in LD with top ten SNPs, the candidate regions defined were mapped to 52.8–59.3 Mb on BTA 4; 67.5–69.3 on BTA 5; 39.5–41.0 Mb on BTA 6; and 26.4–29.6 Mb on BTA 14. The comparison of these candidate regions with the bovine QTLdb effectively confirmed the association (p < 0.05) with QTL related to growth traits and other important productive traits. The genomic regions identified in this study indicated selection for growth traits on the Charolais population via the conservation of haplotypes on various chromosomes. These genomic regions and their associated genes could serve as the basis for haplotype association studies and for the identification of causal genes related to growth traits. [ABSTRACT FROM AUTHOR]

Copyright of Eurasian Journal of Veterinary Sciences is the property of Eurasian Journal of Veterinary Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of study was to evaluate the growth indicators in total of 1,986 purebred Charolais calves in relation to the sex, year of birth, birth season of the calves and also dam's parity. At the same time, the object of work was to evaluate cows' longevity. We found higher values of live weight in bulls (P>0.05), the occurrence of twins showed lower birth weight (P<0.001) and weaning weight (P>0.05). The spring season of calving had an influence on lighter offspring in birth weight (P<0.001) as well as in pre-weaning period (P<0.001); the heaviest calves were born in the winter calving season. Calves born to primiparous cows were markedly lighter at birth (P>0.05), at the age of 120 days (P>0.05), and also at the weaning (P<0.05) than those born to older cows. The linear model characterized by the coefficient of determination for all fixed effects was R² = 0.714862% for birth weight (BLW), R² = 0.375164% for weight at 120 days (LW120) and R² = 0.473550% for weaning weight (LW210). On the basis of the results, we can observe the increased growth performance of calves over the years, pointing to the adaptation of Charolais to conditions in Slovakia. [ABSTRACT FROM AUTHOR]

The significance of breed by environment interaction on suckler cow efficiency traits was investigated, using production data from the Norwegian Beef Cattle Recording System and data collected (feed regimes, etc.) from 27 commercial suckler cow herds. Two statistical approaches were used; mean breed performance in extensive/intensive environments (mixed models), or as within breed regressions of cow performance on modelled cow energy intake. Aberdeen Angus produced higher weaning weight than Hereford below 12,000 MJ NE (241 kg) and Charolais below 13,000 MJ NE (244 kg) cow energy intake in the suckler period, after which the breeds re-ranked. The corresponding re-rank between Hereford and Charolais was at 14,500 MJ NE (263 kg) cow energy intake. Overall, breed by environment interactions were observed for calving interval, number/kg calves weaned/mated cow/year and energy efficiency, which emphasise that choice of cow breed should be dependent on the natural production resources available. [ABSTRACT FROM AUTHOR]

In the present study, the effects of genetic group and heterosis on body measurements of purebreds (Charolais - C and Nellore - N), first-generation crossbreds (G1) (1/2C1/2N and 1/2N1/2C), and second-generation crossbreds (G2) (3/4C1/4N and 3/4N1/4C) males from rotational crossbreeding were evaluated at 8, 12, 18, and 24 months of age. Among the purebreds, the Nellore displayed greater rump height than the Charolais. The Charolais had greater thoracic perimeter than the Nellore, however this difference decreased gradually with advancing age, being equal between the two genetic groups at 24 months. For width of the rump, ischial opening and thoracic perimeter crossbred animals showed higher values than the purebred animals at all ages, but less pronounced at eight months of age. For all morphometric measurements, with exception of rump height, the differences of crossbreds males in relation to the purebreds, were more evident in relation to the Nellore. Heterosis was significant for morphometric measurements in male beef cattle. Morphometric measurements showed high correlation with each other and with body weight, thereby indicating that they are good indicators of body development.

The objective of this study was to compare the effects of a methodology for the climatic season classification that traditionally had been used as birth season (BS) in statistical assessments. This methodology bases in an aridity index (AI) to classify BS using meteorological historic information. Using a 7,460-pedigree animals dataset were fitted two statistical models for birth and weaning weights of Charolais cattle. Genetic models included the fixed effect of contemporary groups (CG= herd, sex, year and BS) and dam age as a covariate (linear and quadratic). Same models compared with a traditional season classification for BS. When variance component and expected progeny differences (EPD) were predicted with their accuracies, models were statistically different accordingly to the likelihood ratio test (P<0.01). An improvement and reduction in CG conformation (25 %) were observed for those models including IA based BS. The main effect in assessed models was the ranking changes in EPD from both traits. This classification method of birth season can improve the model fitting in animal production based in extensive systems. [ABSTRACT FROM AUTHOR]

A study was designed to develop a birth season (BS) classification methodology and assess its impact on live weight traits when compared to a traditional BS classification method. Using meteorological information, and aridity index was computed. The proposed and traditional BS were compared by including them into contemporary groups (CG= herd, sex, year and BS) to adjust genetic evaluation models of studied traits. The variance components and breeding values with accuracies were estimated and compared. The proposed BS explained more phenotypic variation than traditional (=9.8%). Genetic parameters showed important changes, more evident for weaning weight. According to the likelihood ratio test the compared models were statistically different (P<0.01). An improvement in CG structure was observed. Genetic correlations of breeding values showed important differences suggesting hierarchy changes. This method of BS classification might improve the statistical model fitting when meteorological information could be available. [ABSTRACT FROM AUTHOR]

We assessed through the weight of cows and calves up to weaning at 90 days and the reproductive performance from pregnancy to weaning, the productivity and efficiency of 94 Charolais (CH), Nellore (NE), ½CH ½NE e ½NE ½CH cows submitted the following feeding systems: cows kept on native pasture (NP); cows kept on cultivated pasture (CP), composed of oat (Avena sativa), ryegrass (Lollium multiflorum) and clover (Trifolium vesiculosum) from July 15 to September 15 and the remainder of the trial on natural pasture (CPN); and cows kept on cultivated pasture during September 15 to November 15, and the remainder on native pasture (NPC). Cows kept on CP produced 22.6% more calves than cows kept exclusively on NP, and were more efficient (P.05), being higher than the purebreds in productivity and production efficiency

Copyright of Canadian Journal of Animal Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The data of dynamic change of live weight of the experimental young received during pure breeding and interbreeding breeding are given. One of the methods for improving the meat sector in sheep breeding is the industrial interbreeding, the effectiveness of which depends on the combining ability of the source material. Industrial cross-breeding makes it possible to successfully combine the good meat qualities of an improving breed with the desirable features (adaptation to local conditions, feeding, keeping, peculiarities of the wool, etc.) of the local breed. The full development of young sheep in the embryonic period is a live weight at birth. The level of live weight at weaning indicates the development of lambs in the period of postnatal ontogenesis and breastfeeding of mothers. The researches have established, that the crossbreeding of the Charolais sheep with the rams of the Askanian meat and wool breed of the Dnipropetrovsk type are dominated by peers (AMD) according to the intensity of growth and development. The live weight at birth is 4.3 ± 0.2 kg, which is 4.9% more compared with pureborn peers. By live weight at 40 days of age, the locusts younger than Charolais dominate pure-blooded peers at the level of 18.2%, which is a significant indicator of the effective use of feed, and their transformation into products with a growth factor of 2.86 - 3.22. Sexual dimorphism for a live weight of maximum level reaches 90 days of age. Relative rams on the body mass index dominate the brightness from 4.3% at birth to 30.7% in 90 days. A comparative analysis of the premature mass of lamb in the age of 120 days indicates the advantage of mares to pure-blooded peers of AMD at 35.7%, which further provides a difference between the groups in the mass of carcass and the mortality of 5.7 kg and 5.1% respectively. According to the indicators of the slaughtered outlet, the landed young is dominated by pure-blooded AMD at the age of 4 months by 5.1%; in 12 months - by 5.0%. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of beef cattle breed and muscle type on the proximate chemical composition and quality traits of meat, including processing suitability. The experimental materials comprised samples of musculus longissimus dorsi (LD muscle) and musculus semitendinosus (ST muscle) collected from the carcasses of young Limousin, Charolais and Hereford bulls. The chemical composition, texture, hydration and color parameters of LD and ST muscles were determined. Meat from Limousin and Charolais bulls, characterized by higher body mass at slaughter contained more protein than meat from Hereford bulls. Meat from Hereford bulls had a higher fat content, compared with the other two breeds. Texture parameters, including hardness, gumminess and chewiness, varied depending on muscle type and cattle breed. An analysis of the maximum shear force values showed that the mechanical properties of beef also varied depending on cattle breed and muscle type.

The objective was to assess the performance of 96 pregnant cows of the genetic groups (GG) Charolais (C), Nellore (N), ½ CN and ½ NC, subjected to the following treatments: kept exclusively in natural pastures (NP) throughout the experimental period; kept in cultivated pastures (CP) from July 15 to Setp 15 (CPNP) or from Sept 15 to Nov 15 (NPCP) and the remainder of the experimental period in NP. The weight at the end of the first grazing period (Sept 15) was higher for the CPNP cows than those of the NPCP and NP. The weight at the end of the second period (Nov 15) was 456, 428 and 392 kg respectively for NPCP, CPNP and NP. At calving, the heaviest cows were the CPNP, followed by the NPCP and the NP. At weaning, 90 days postpartum, the heaviest were the NPCP, followed by the CPNP and NP. Nelore cows were less heavy in all evaluations, followed by C, with the F1s' weight higher than the purebreds. The grazing sequences did not affect the percentages of the cows in estrus and pregnancy, but did influence the invervals between calving and first estrus postpartum (ICE). The GG influenced the rate of cows in estrus, pregnant and the ICE which was lower in the F1 (103 days), followed by the C (109 days) and had the largest interval N (119 days). The grazing sequences affect the average daily weight gain (ADG) of calves until weaning at 90 days of age. The GG of the calf affected the ADG at to 210 days.

The objective of this experiment was to study the development and reproductive performance of sixty-six Charolais crossbred beef heifers bred at fourteen months of age, classified in four groups according to pre and postweaning average daily weight gain (ADG): AA= heifers that showed ADG > .54 kg and .73 kg, respectively; AB= heifers that showed ADG > .54 kg and < .73 kg, respectively; BA= heifers that showed ADG < .54 kg and > .73 kg, respectively; BB= heifers that showed ADG < .54 kg and < .73 kg, respectively. Weight at the beginning and end of the breeding period, and the reproductive performance were influenced by ADG of the heifers during pre and postweaning phase. AA heifers showed better development in relation to the other groups, without difference between AB and BA. The AA group was superior to the others except for the reproductive performance of the group AB. Heifers that became cyclical showed higher development during the growing phase and mating period than acyclic heifers. Reproductive performance of heifers was positively correlated with weight and body condition at beginning and end of the mating period. Greater weight during pre and post-weaning improve the reproductive performance of beef heifers.

Avaliou-se o desempenho de novilhas de corte até o parto submetidas a diferentes níveis de suplementação em pastagem natural durante o primeiro período reprodutivo, dos 14 aos 17 meses. Foram utilizadas 98 novilhas contemporâneas do mesmo rebanho dos grupos genéticos Charolês, Nelore e suas cruzas, com peso médio de 255 kg. As novilhas foram distribuídas em três grupos: sem suplementação; com suplementação de 3,5 g/kg do peso corporal; com suplementação de 7,0 g/kg do peso corporal. O peso ao final e o ganho de peso médio diário durante o período de suplementação foi maior entre as novilhas do grupo com suplementação na proporção de 7,0 g/kg (322 e 0,701 kg) em comparação àquelas sob suplementação na proporção de 3,5 g/kg (302 e 0,464 kg) e sem suplementação (288 e 0,425 kg), que não diferiram entre si. O escore de condição corporal ao final da suplementação diferiu entre os três grupos com 3,07; 3,33 e 3,47 pontos, respectivamente, para novilhas sem suplementação; com suplementação na proporção de 3,5 g/kg do peso corporal; com suplementação na proporção de 7,0 g/kg do peso corporal. A porcentagem de prenhez foi influenciada significativamente pelo nível de suplementação, sendo de 35,0; 34,2 e 70,0%, respectivamente. Os dois grupos sob suplementação tiveram maior taxa de concepção na metade inicial do período reprodutivo. A média de idade das novilhas ao parto foi de 785, 778 e 761 dias, respectivamente. O ganho médio diário e a condição corporal foram semelhantes entre as novilhas dos dois grupos genéticos, porém o peso ao início e ao final do período de suplementação foi maior nas filhas de touros charoleses em relação às de touros nelores, refletindo-se nas taxas de manifestação de estro (68,8 vs. 38,2) e de prenhez (60,9 vs. 26,5). As características relacionadas ao parto das novilhas não foram influenciadas pelos níveis de suplementação durante o período reprodutivo. A suplementação durante o período de acasalamento aumenta o desempenho reprodutivo de novilhas aos 14 meses de idade.The objective was to evaluate the performance of beef heifers until calving receiving different levels of supplementation on native pasture during the first breeding season, from 14 to 17 months: no supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight. Ninety-eight Charolais, Nellore and their crosses, with average initial weight of 255 kg, were used. Weight at the end and average daily weight gain during the supplementation period were higher for 7.0 g/kg of supplement heifers (322 and 0.701 kg) compared to those with 3.5 g/kg of supplement (302 and 0.464 kg) and heifers without supplementation (288 and 0.425 kg), which did not differ from each other. Body condition score at the end of the supplementation was different between the three treatments, being 3.03, 3.33 and 3.47 points for heifers without supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight, respectively. Pregnancy rate was significantly affected by supplementation level, being 35.0, 34.2 and 70.0%, respectively. Heifers of the two supplementation treatments had higher conception rate at the first half of the reproductive period. Average heifer ages at calving were of 785, 778 and 761 days, respectively. The average daily weight and body condition of the heifers of the two genetic groups were similar; however, the initial and final weight of the supplementation period was higher for Charolais bulls daughters, compared with Nellore bulls daughters, reflecting on the heat (68.8 vs. 38.2%) and pregnancy (60.9 vs. 26.5%) rates. Characteristics related to calving were not affected by the supplementation levels during the reproductive period. The supplementation during the first breeding season increases reproductive performance of heifers at 14 months of age.

The effect of energetic supplementation, in the form of grounded oat grain (OT), associated with urea (OTU), with monensin (OTM), or with urea plus monensin (OTUM), on the performance of 116 Charolais (C), Nellore (N) and crossbreds with predominance of C (CN) or N (NC) heifers was evaluated during the end of summer (ES) and beginning of autumn (BA). The 15-month-old heifers, with initial weight of 243.1 kg, were kept on native pasture and supplemented with an amount of .7% of live weight. The average daily weight gain (ADG) was higher for heifers supplemented with the combination OTUM (538 g) in relation to OT (430 g) and OUT (380 g), however it was statistically similar to the combination OTM (488 g). Treatments that included monensin showed higher efficiency of converting the supplement into weight gain. During ES, the ADG was higher than during the BA (525 vs 394 g). For C, CN, N and NC heifers, the ADG during ES was 370, 517, 560 and 691 g and during BA it was 427, 398, 317 and 397 g, respectively. Nellore heifers showed lower live weight than the other genetic groups. Body condition score at the end of ES and BA was higher for CN heifers which did not differ from NC, with C showing intermediate score and N showing the lowest score. The monensin and urea association promotes weight gain of animals kept on native pastures and supplemented with oat grain.

Objetivou-se com este estudo avaliar as características dos componentes externos e da gordura de descarte de novilhos de duas condições sexuais e dois genótipos terminados em confinamento. A idade e o peso médios dos animais ao início do período experimental foram de 12 meses e 267,0 kg, respectivamente. Os novilhos foram confinados até atingirem o peso de abate pré-estabelecido médio de 400 kg. A dieta foi formulada com relação volumoso:concentrado de 50:50, com base na matéria seca, com 10% de proteína bruta. O delineamento experimental utilizado foi o inteiramente casualizado, em arranjo fatorial de 2 × 2, composto de duas condições sexuais e dois grupos genéticos. O peso de corpo vazio (PCV), os rendimentos de carcaça em relação ao peso de corpo vazio e a relação entre o peso de corpo vazio e o peso de abate foram similares entre genótipos e condições sexuais. Para o peso absoluto das orelhas, observou-se interação significativa entre genótipo e condição sexual dos novilhos. Animais castrados apresentaram maiores valores de gordura intestinal em relação ao peso de corpo vazio (1,62 versus 1,18%) e ao peso ao abate (1,41 versus 1,02%) e de cabeça em relação ao peso ao abate (3,78 versus 3,29%). Os animais com predominância de sangue Charolês apresentaram maior peso absoluto de vassoura da cauda (0,16 versus 0,11 kg) e novilhos Nelore maiores pesos relativos de couro e gordura renal. Não há correlação entre o rendimento de carcaça e os componentes não-integrantes da carcaça.The objective of this study was to evaluate the characteristics of external components and discard fat of young steers with two different sexual conditions and two different genotypes, finished in feedlot. Average age and weight of the animals at the beginning of the experimental period were 12 months and 267.0 kg, respectively. The steers were in feedlot until reaching pre-established slaughter weight of 400 kg. Diet contained roughage:concentrate ratio of 50:50, on dry matter basis, with 10% crude protein. It was used a complete randomized experimental design, in a 2 × 2 factorial arrangement, composed of two sexual conditions and two genetic groups. Empty body weight (EBW), carcass dressing in relation to empty body weight and the relationship between empty body weight and slaughter weight were similar among genotypes and sexual conditions. For absolute weight of ears, it was observed significant interaction between genotypes and sexual conditions of steers. Castrated animals showed greater values of intestinal fat in relation to empty body weight (1.62 versus 1.18%). Animals with Charolais predominance showed greater absolute values to tail broom (0.16 versus 0.11 kg) and Nellore steers predominance presented greater weight related to rawhide and renal fat. There is no correlation among carcass dressing and non-integrant components of carcass.

O estudo foi realizado com o objetivo de avaliar as características de carcaça de novilhos e vacas de descarte de dois grupos genéticos sob diferentes frequencias de alimentação. Foram utilizados 12 novilhos e 12 vacas de descarte, de modo que cada categoria foi formada de seis animais 5/8 Charolês (C) - Nelore (N) e seis animais 5/8NC, submetidos a três frequencias alimentação; duas vezes ao dia (às 7 e 19 h); três vezes ao dia (às 7, 13 e 19 h); e quatro vezes ao dia (às 7, 11, 15 e 19 h). Os animais foram terminados em confinamento recebendo como volumoso silagem de milho e concentrado à base de farelo de trigo, grão de milho moído, farelo de soja, calcário calcítico e sal, com relação volumoso:concentrado 40:60. O aumento na frequência de alimentação não influenciou a qualidade da carcaça dos animais. As vacas apresentaram maiores pesos de abate e de carcaça quente e fria (509,7; 280,0; e 277,1 kg) em comparação aos novilhos (414,5; 230,5 e 228,1 kg), no entanto, os rendimentos de carcaça quente e fria e as perdas por resfriamento foram semelhantes entre novilhos e vacas de descarte. As características que expressam a musculosidade da carcaça foram melhores nas vacas, que apresentaram maior espessura de coxão (25,88 vs 23,33 cm). As características métricas foram mais expressivas nas vacas, que tiveram carcaças mais longas (132,8 vs 122,3 cm) e maior espessura de gordura (6,21 vs 3,83 mm). As vacas também foram superiores quanto aos pesos de dianteiro e traseiro (103,5 e 133,0 kg) em comparação aos novilhos (84,7 e 111,8 kg), que apresentaram maior percentual de traseiro na carcaça (49,06 vs 48,04%). Entre os grupos genéticos, os animais 5/8C 3/8N apresentaram maior espessura de coxão, área do músculo Longissimus dorsi e comprimento de carcaça (25,7 cm; 64,0 cm² e 137,0 cm) em comparação aos 5/8N 3/8C (23,5 cm; 57,0 cm² e 124,8 cm).The objective of this study was to evaluate carcass characteristics of steers and cull cows from two genetic groups, under different feeding frequencies. Twelve steers and twelve cull cows were used and each category consisted of six animals 5/8 Charolais (C) - Nellore (N) and six animals 5/8NC, under three feeding frequencies: twice a day (7 a.m. and 7 p.m.); three times a day (7 a.m., 1 p.m. and 7 p.m.) and four times a day (7 a.m., 11 a.m., 3 p.m. and 7 p.m.). The animals were feedlot finished receiving corn silage as forage and concentrate based on wheat bran, corn ground, soybean meal, limestone and salt, with a forage:concentrate ratio of 40:60. The increase in feeding frequency did not influence the animal carcass quality. The cows showed higher slaughter, hot and cold carcass weights (509.7; 280.0; and 277.1 kg) compared to the steers (414.5; 230.5 and 228.1 kg), but the hot and cold carcass dressing percentages and carcass chilling loss were similar in the steers and cull cows. The characteristics that express carcass muscularity were better in the cows that had greater thigh thickness (25.88 vs 23.33 cm). The metrical characteristics were more expressive in the cows which had longer carcasses (132.8 vc 122.3 cm) and greater fat thickness (6.21 vs 3.83 mm). The cows also were superior for forequarter and sawcut weights (103.5 and 133 kg) compared to the steers (84.7 and 111.8 kg), which presented higher sawcut percentage in the carcass (49.06 vs 48.04%). Between the genetic groups, 5/8C3/8N animals presented higher thigh thickness, Longissimus dorsi area and carcass length (25.7 cm; 64 cm² and 137 cm) compared to 5/8N3/8C (23.5 cm; 57 cm² and 124.8 cm).