Performance and incidence of diarrhea in suckling Jersey calves supplemented with mineral-vitamin complex and Virginiamycin.

The rearing of calves is an essential activity of a dairy system, as it impacts the future production of these animals. This study aims to evaluate the incidence of diarrhea, performance, and blood parameters of suckling calves that received mineral-vitamin supplementation in milk plus virginiamycin that was offered in milk (via the abomasum) or by esophageal tube (via the rumen). Twenty-seven calves were used, from the first week to 60 days of age, submitted to the following treatments: CONTROL, without supplementation; MILK, supplementation of 20 g of a mineral-vitamin complex with 100 mg of virginiamycin, diluted in milk; RUMEN, supplementation of 20 g of a mineral-vitamin complex diluted in milk and 100 mg of virginiamycin in gelatin capsules via an esophageal applicator. MILK and RUMEN calves had lower fecal consistency scoring, fewer days with scores 2 and 3 throughout the experimental period, and lower spending on medication compared to the CONTROL animals. Supplemented calves had higher fat and protein intake and reached feed intake of 600 g earlier than CONTROL animals, but did not differ in performance and hematological parameters. Supplementation with virginiamycin and vitamin-mineral complex for suckling calves reduced the incidence and days of diarrhea, and reduced medication costs, with no difference in performance, but the supplemented animals had higher initial protein and fat intake and reached targeted feed intake earlier to begin the weaning process.

Genetic association between fat-to-protein ratio and traits of economic interest in early lactation Holstein cows in Brazil.

The aims of this study were to estimate the genetic parameters for fat-to-protein ratio (F:P) within the first 90 days of lactation and to examine their genetic associations with daily milk yield (MY), somatic cell score (SCS), and calving interval between the first and second calving (IFSC) and between the second and third calving (ISTC) during the first three lactations of Holstein cows. We utilized 200,626 production-related data officially recorded from 77,436 cows milked two or three times a day from 2012 to 2022, sourced from the Holstein Cattle Breeders Association of Paraná State, Brazil. The (co)variance components were estimated using animal models, adopting the restricted maximum likelihood (REML) method with single-trait analysis (for heritability and repeatability) and two-trait analysis (for genetic and phenotypic correlations), per lactation. Regardless of lactation number, heritability estimates were relatively low, ranging from 0.08 ± 0.005 to 0.10 ± 0.003 for F:P; 0.08 ± 0.01 to 0.18 ± 0.005 for MY; 0.04 ± 0.01 to 0.07 ± 0.004 for SCS; and 0.03 ± 0.01 for both IFSC and ISTC. Repeatability estimates within the same lactation were low for F:P (ranging from 0.17 ± 0.002 to 0.19 ± 0.03), high for MY (between 0.50 ± 0.003 and 0.53 ± 0.002), and moderate to high for SCS (between 0.39 ± 0.003 and 0.44 ± 0.004). Genetic correlations between F:P and MY ranged from -0.26 ± 0.03 to -0.15 ± 0.02; F:P and SCS, from -0.06 ± 0.03 to -0.03 ± 0.08; F:P and IFSC, 0.31 ± 0.01; F:P and ISTC, 0.20 ± 0.01; MY and IFSC, 0.24 ± 0.05; and MY and ISTC, 0.13 ± 0.08. The fat-to-protein ratio during early lactation showed low genetic variability, regardless of lactation number. Furthermore, it was genetically correlated with MY, IFSC, and ISTC, although there is an antagonistic and unfavorable correlation between traits that can limit genetic progress.

Genomic prediction in Brazilian Guzerá cattle: application of a single-step approach to productive and reproductive traits.

This study aimed to investigate the feasibility of genomic prediction for productive and reproductive traits in Guzerá cattle using single-step genomic best linear unbiased prediction (ssGBLUP). Evaluations included the 305-day cumulative yields (first lactation, in kg) of milk, lactose, protein, fat, and total solids; adjusted body weight (kg) at the ages of 450, 365, and 210 days; and age at first calving (in days), from a database containing 197,283 measurements from Guzerá males and females born between 1954 and 2018. The pedigree included 433,823 animals spanning up to 14 overlapping generations. A total of 1618 animals were genotyped. The analyses were performed using ssGBLUP and traditional BLUP methods. Predictive ability and bias were accessed using cross-validation: predictive ability was similar between the methods and ranged from 0.27 to 0.47 for the genomic-based model and from 0.30 to 0.45 for the pedigree-based model; the bias was also similar between the methods, ranging from 0.88 to 1.35 in the genomic-based model and from 0.96 to 1.41 in the pedigree-based model. The individual accuracies of breeding values were evidently increased in the genomic evaluation, with values ranging from 0.41 to 0.56 in the genomic-based model and from 0.26 to 0.54 in the pedigree-based model. Even based on a small number of genotyped animals and a small database for some traits, the results suggest that ssGBLUP is feasible and may be applied to national genetic evaluation of the breed to increase the accuracy of breeding values without greatly impacting predictive ability and bias.

Effect of Thermal Stress on Thermoregulation, Hematological and Hormonal Characteristics of Caracu Beef Cattle.

This study evaluated the influence of environmental temperature on thermoregulation, hormonal, and hematological characteristics in Caracu cattle. Blood samples, hair length, coat and muzzle colors, rectal (RT), and surface temperatures were collected from 48 males and 43 females before (morning) and after sun exposure for eight hours (afternoon). Infrared thermography (IRT) was used to identify superficial temperature that exhibits a high correlation with RT. Hematological parameters, hormone concentrations, RT, and the superficial temperature obtained by IRT that exhibited the highest correlation with RT were evaluated by variance analysis. Regarding IRT, the lower left side of the body (LS) showed the highest correlation with the RT. Interaction between period and sex was observed for LS, cortisol, and eosinophils. Cortisone, progesterone, and RT were influenced by period and sex. Neutrophils and segmented neutrophils were influenced by the period, which showed the highest concentrations after sun exposure. Platelets, leukocytes, lymphocytes, and monocytes were influenced by sex. Heat stress changes several physiological characteristics where males and females exhibited differences in their responses to heat stress. Furthermore, most characteristics evaluated remained within the regular values observed for taurine Creole breeds, showing that Caracu is adapted to tropical climates.

Genetic study of quantitative traits supports the use of Guzerá as dual-purpose cattle.

OBJECTIVE: The aim of this study was to estimate genetic parameters for 305-day cumulative milk yield and components, growth, and reproductive traits in Guzerá cattle. METHODS: The evaluated traits were 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), protein (PY305), lactose (LY305), and total solids (SY305); age at first calving (AFC) in days; adjusted scrotal perimeter (cm) at the ages of 365 (SP365) and 450 (SP450) days; and adjusted body weight (kg) at the ages of 210 (W210), 365 (W365), and 450 (W450) days. The (co)variance components were estimated using the restricted maximum likelihood method for single-trait, bi-trait and tri-trait analyses. Contemporary groups and additive genetic effects were included in the general mixed model. Maternal genetic and permanent environmental effects were also included for W210. RESULTS: The direct heritability estimates ranged from 0.16 (W210) to 0.32 (MY305). The maternal heritability estimate for W210 was 0.03. Genetic correlation estimates among milk production traits and growth traits ranged from 0.92 to 0.99 and from 0.92 to 0.99, respectively. For milk production and growth traits, the genetic correlations ranged from 0.33 to 0.56. The genetic correlations among AFC and all other traits were negative (-0.43 to -0.27). Scrotal perimeter traits and body weights showed genetic correlations ranging from 0.41 to 0.46, and scrotal perimeter and milk production traits showed genetic correlations ranging from 0.11 to 0.30. The phenotypic correlations were similar in direction (same sign) and lower than the corresponding genetic correlations. CONCLUSION: These results suggest the viability and potential of joint selection for dairy and beef traits in Guzerá cattle, taking into account reproductive traits.

Somatic cell count obtained by Ekomilk Scan® and correlations with other methods of analysis / Contagem de células somáticas obtidas pelo equipamento Ekomilk Scan ® e suas correlações com outros métodos de análise

The study aimed to evaluate the equipment Ekomilk Scan® as an alternative to somatic cell count (SCC) in milk. For this individual cow milk samples of various ages and different stages of lactation in northeastern state of São Paulo region were collected. The analyzes performed were divided into variables related to the equipment: repeatability and reproducibility, and variables that could influencing the results as: use of preservatives, temperature, time between collection and analysis, breed and milk composition, besides analysis to relate the Ekomilk Scan® with the standard method-direct microscopy and reference-flow cytometry. As the result, for samples analysis, it shouldnt be added preservative and these should be conducted on the same day of collection; however, temperature sample did not significantly influence results. Furthermore, Ekomilk Scan® did not show good correlation of results with the method of direct microscopy; however, it was necessary to generate equations for a positive correlation between flow cytometry and Ekomilk Scan®. Therefore, it is concluded that the equipment tested is not accurate but it can be an alternative for SCC monitoring in productive units since it uses calibration equations of results.(AU)

O estudo objetivou avaliar o equipamento Ekomilk Scan® como uma alternativa para a contagem de células somáticas (CCS) no leite. Para isso, foram colhidas amostras individuais de leite de vaca de várias idades em diferentes estágios de lactação na região nordeste do estado de São Paulo. Foram realizadas análises referentes ao equipamento como repetibilidade e reprodutibilidade, e de variavéis que poderiam influenciar no resultado. Dentre elas: uso de conservante, temperatura, tempo entre a colheita e análise, raça e composição do leite, além de análises visando correlacionar o Ekomilk Scan® com o método padrão-microscopia direta e de referência-citometria de fluxo. Como resultado, foi observado que para as análises das amostras não se deve acrescentar conservante e estas devem ser realizadas no mesmo dia da colheita, porém a temperatura da amostra não possui influencia significativa nos resultados. O Ekomilk Scan® não demonstrou boa correlação dos resultados com o método de microscopia direta e citometria de fluxo, sendo necessário gerar equações para uma correlação positiva entre os métodos. Assim, conclui-se que o equipamento testado não apresenta resultados precisos, contudo pode ser uma alternativa para o monitoramento da CCS em unidades produtivas desde que utilize equações de calibração dos resultados.(AU)

Somatic cell count obtained by Ekomilk Scan® and correlations with other methods of analysis / Contagem de células somáticas obtidas pelo equipamento Ekomilk Scan ® e suas correlações com outros métodos de análise

ABSTRACT: The study aimed to evaluate the equipment Ekomilk Scan® as an alternative to somatic cell count (SCC) in milk. For this individual cow milk samples of various ages and different stages of lactation in northeastern state of São Paulo region were collected. The analyzes performed were divided into variables related to the equipment: repeatability and reproducibility, and variables that could influencing the results as: use of preservatives, temperature, time between collection and analysis, breed and milk composition, besides analysis to relate the Ekomilk Scan® with the standard method-direct microscopy and reference-flow cytometry. As the result, for samples analysis, it shouldn't be added preservative and these should be conducted on the same day of collection; however, temperature sample did not significantly influence results. Furthermore, Ekomilk Scan® did not show good correlation of results with the method of direct microscopy; however, it was necessary to generate equations for a positive correlation between flow cytometry and Ekomilk Scan®. Therefore, it is concluded that the equipment tested is not accurate but it can be an alternative for SCC monitoring in productive units since it uses calibration equations of results.

RESUMO: O estudo objetivou avaliar o equipamento Ekomilk Scan® como uma alternativa para a contagem de células somáticas (CCS) no leite. Para isso, foram colhidas amostras individuais de leite de vaca de várias idades em diferentes estágios de lactação na região nordeste do estado de São Paulo. Foram realizadas análises referentes ao equipamento como repetibilidade e reprodutibilidade, e de variavéis que poderiam influenciar no resultado. Dentre elas: uso de conservante, temperatura, tempo entre a colheita e análise, raça e composição do leite, além de análises visando correlacionar o Ekomilk Scan® com o método padrão-microscopia direta e de referência-citometria de fluxo. Como resultado, foi observado que para as análises das amostras não se deve acrescentar conservante e estas devem ser realizadas no mesmo dia da colheita, porém a temperatura da amostra não possui influencia significativa nos resultados. O Ekomilk Scan® não demonstrou boa correlação dos resultados com o método de microscopia direta e citometria de fluxo, sendo necessário gerar equações para uma correlação positiva entre os métodos. Assim, conclui-se que o equipamento testado não apresenta resultados precisos, contudo pode ser uma alternativa para o monitoramento da CCS em unidades produtivas desde que utilize equações de calibração dos resultados.

Associação genética entre ocorrência de mastite clínica e produção de leite em vacas Holandesas / Genetic association between clinical mastitis occurrence and milk yield in Holstein cows

RESUMO:O objetivo deste trabalho foi estimar os parâmetros genéticos e fenotípicos para ocorrência da mastite clínica (MC) e para a produção de leite acumulada até 305 dias (PR305) e estudar as associações genéticas entre elas, usando informações de 11.738 lactações de 5.084 vacas de um rebanho da raça Holandesa, paridas entre 1995 a 2010. Os componentes de covariância foram obtidos por abordagem Bayesiana, sob modelo animal. As estimativas de herdabilidade para a PR305 e para a MC foram de 0,16 (0,02) e 0,11 (0,02), respectivamente, e as repetibilidades foram 0,34 (0,012) e 0,21 (0,02), para PR305 e MC, respectivamente. A correlação genética entre a PR305 e a MC foi negativa e de baixa magnitude (-0,21±0,13). As estimativas de herdabilidade para PR305 e MC indicam que estas características são influenciadas por fatores ambientais, entretanto há suficiente variabilidade genética para obtenção de ganhos através da seleção.

ABSTRACT:The objective of this study was to estimate genetic and phenotypic parameters for the occurrence of clinical mastitis (MC) and milk production during lactation (PR305) and study the genetic associations between them, using information from 11,738 lactations of 5,084 Holstein herd cows, that calved from 1995 to 2010. The covariance components were estimated by Bayesian inference using the animal model. Heritability estimates for the PR305 and the MC were 0.16 (0.02) and 0.11 (0.02), respectively and repeatability were 0.34 (0.012) for PR305 and 0.21 (0.02) for MC. The genetic correlation between the PR305 and the MC was negative and of low magnitude (-0.21±0.13). Heritability estimates for PR305 and MC indicate that these characteristics are influenced by environmental factors, however there is enough genetic variability to obtain gains through selection.

Associação genética entre ocorrência de mastite clínica e produção de leite em vacas Holandesas / Genetic association between clinical mastitis occurrence and milk yield in Holstein cows

O objetivo deste trabalho foi estimar os parâmetros genéticos e fenotípicos para ocorrência da mastite clínica (MC) e para a produção de leite acumulada até 305 dias (PR305) e estudar as associações genéticas entre elas, usando informações de 11.738 lactações de 5.084 vacas de um rebanho da raça Holandesa, paridas entre 1995 a 2010. Os componentes de covariância foram obtidos por abordagem Bayesiana, sob modelo animal. As estimativas de herdabilidade para a PR305 e para a MC foram de 0,16 (0,02) e 0,11 (0,02), respectivamente, e as repetibilidades foram 0,34 (0,012) e 0,21 (0,02), para PR305 e MC, respectivamente. A correlação genética entre a PR305 e a MC foi negativa e de baixa magnitude (-0,21±0,13). As estimativas de herdabilidade para PR305 e MC indicam que estas características são influenciadas por fatores ambientais, entretanto há suficiente variabilidade genética para obtenção de ganhos através da seleção.(AU)

The objective of this study was to estimate genetic and phenotypic parameters for the occurrence of clinical mastitis (MC) and milk production during lactation (PR305) and study the genetic associations between them, using information from 11,738 lactations of 5,084 Holstein herd cows, that calved from 1995 to 2010. The covariance components were estimated by Bayesian inference using the animal model. Heritability estimates for the PR305 and the MC were 0.16 (0.02) and 0.11 (0.02), respectively and repeatability were 0.34 (0.012) for PR305 and 0.21 (0.02) for MC. The genetic correlation between the PR305 and the MC was negative and of low magnitude (-0.21±0.13). Heritability estimates for PR305 and MC indicate that these characteristics are influenced by environmental factors, however there is enough genetic variability to obtain gains through selection.(AU)

Principal components analysis for growth traits in beef cattle / Análise de componentes principais para características de crescimento em bovinos de corte

The objetive of this research was to study the relation among body weight and average daily gain indifferent ages, using principal components analysis. Data on 1663 birth weight (BW), weaning weightadjusted to 230 days (WW), yearling weight adjusted to 365 days (YW), long yearling weight adjustedto 550 days (LYW), average daily gain from birth to weaning (AGW), average daily gain from weaningto 365 days (AGY) and average daily gain from 365 days weight to 550 day weight (AGL) fromcrossbred animals, and data on 320 observations of the same traits from straightbreed Nellore animalswere analysed. The model included the fixed effects of breed (only crossbred data), contemporary group, and linear and quadratic effects of age at calving. For body weight in different ages, the firstprincipal component contrasted heavier and light animals after birth and explained about 79,0% and78,0% of the variation for data on crossbred and Nellore animals, respectively. The second principalcomponent compared heavier animals at weaning and yearling weight those at long yearling weight .It explained around 13,5% and 15,5% of the total variation, respectively, for data on F1 and Nellorebreed. The major source of variation among animals on the two data set for body weight was due todifferences in weight followed by differences in the ages they got those weight. For the traits expressedas average daily gain, the variation among animals was due to differences in birth season, the firstprincipal component explaining about 52,0% of the variation on crossbred animals. This componentcompared animal with higher AGY with those with higher AGW and AGL. For data on Nellore breed,the first component explain about 56,0% of the total variation and also compared animals with higherAGY with those with higher AGW and AGL.(AU)

Com o objetivo de estudar as inter-relações entre pesos e entre ganhos médios diários, utilizando-se a técnica de componentes principais, foram utilizadas 1663 observações de pesos ao nascimento (PN), a desmama ajustado para 230 dias (PD), ao ano ajustado para 365 dias (P365), ao sobreano ajustado para 550 dias de idade (P550) e ganho médio diário do nascimento à desmama (GND), da desmama a um ano de idade (G365) e dos 365 dias aos 550 dias de idade (G550) de um rebanho de animais cruzados F1, e um segundo arquivo contendo 320 observações das mesmas características de animais puros da raça Nelore. O modelo matemático para todas as características incluíram os efeitos de grupo de contemporâneos e os efeitos linear e quadrático da idade da vaca ao parto, enquanto o efeito fixo de raça foi considerado apenas para o arquivo de animais F1. Para os pesos, o primeiro componente principal contrastou animais mais pesados com animais mais leves após o nascimento, e explicou 79,0% e 78,0% da variação total para os arquivos contendo animais F1 e puros Nelore, respectivamente. O segundo componente principal comparou animais que atingiram maiores pesos na desmama com animais que foram mais pesados aos 550 dias de idade, explicando 13,5% e 15,5% da variação total para os arquivos de animais F1 e puros Nelore, respectivamente. A maior fonte de variação entre animais foi devida às diferenças em peso, seguida por diferenças nas idades nas quais os animais atingiram maiores pesos.Para o ganho médio diário nas diferentes idades, a variação entre animais foi principalmente devido àsdiferentes épocas de nascimento. O primeiro componente principal, explicou 52,0% e 56% da variaçãototal para animais F1 e Nelore, respectivamente. Esse componente contrastou animais de maiores G365com animais de maiores GND e G550, respectivamente, para animais F1 e Nelore.(AU)

Principal components analysis for growth traits in beef cattle / Análise de componentes principais para características de crescimento em bovinos de corte

The objetive of this research was to study the relation among body weight and average daily gain indifferent ages, using principal components analysis. Data on 1663 birth weight (BW), weaning weightadjusted to 230 days (WW), yearling weight adjusted to 365 days (YW), long yearling weight adjustedto 550 days (LYW), average daily gain from birth to weaning (AGW), average daily gain from weaningto 365 days (AGY) and average daily gain from 365 days weight to 550 day weight (AGL) fromcrossbred animals, and data on 320 observations of the same traits from straightbreed Nellore animalswere analysed. The model included the fixed effects of breed (only crossbred data), contemporary group, and linear and quadratic effects of age at calving. For body weight in different ages, the firstprincipal component contrasted heavier and light animals after birth and explained about 79,0% and78,0% of the variation for data on crossbred and Nellore animals, respectively. The second principalcomponent compared heavier animals at weaning and yearling weight those at long yearling weight .It explained around 13,5% and 15,5% of the total variation, respectively, for data on F1 and Nellorebreed. The major source of variation among animals on the two data set for body weight was due todifferences in weight followed by differences in the ages they got those weight. For the traits expressedas average daily gain, the variation among animals was due to differences in birth season, the firstprincipal component explaining about 52,0% of the variation on crossbred animals. This componentcompared animal with higher AGY with those with higher AGW and AGL. For data on Nellore breed,the first component explain about 56,0% of the total variation and also compared animals with higherAGY with those with higher AGW and AGL.

Com o objetivo de estudar as inter-relações entre pesos e entre ganhos médios diários, utilizando-se a técnica de componentes principais, foram utilizadas 1663 observações de pesos ao nascimento (PN), a desmama ajustado para 230 dias (PD), ao ano ajustado para 365 dias (P365), ao sobreano ajustado para 550 dias de idade (P550) e ganho médio diário do nascimento à desmama (GND), da desmama a um ano de idade (G365) e dos 365 dias aos 550 dias de idade (G550) de um rebanho de animais cruzados F1, e um segundo arquivo contendo 320 observações das mesmas características de animais puros da raça Nelore. O modelo matemático para todas as características incluíram os efeitos de grupo de contemporâneos e os efeitos linear e quadrático da idade da vaca ao parto, enquanto o efeito fixo de raça foi considerado apenas para o arquivo de animais F1. Para os pesos, o primeiro componente principal contrastou animais mais pesados com animais mais leves após o nascimento, e explicou 79,0% e 78,0% da variação total para os arquivos contendo animais F1 e puros Nelore, respectivamente. O segundo componente principal comparou animais que atingiram maiores pesos na desmama com animais que foram mais pesados aos 550 dias de idade, explicando 13,5% e 15,5% da variação total para os arquivos de animais F1 e puros Nelore, respectivamente. A maior fonte de variação entre animais foi devida às diferenças em peso, seguida por diferenças nas idades nas quais os animais atingiram maiores pesos.Para o ganho médio diário nas diferentes idades, a variação entre animais foi principalmente devido àsdiferentes épocas de nascimento. O primeiro componente principal, explicou 52,0% e 56% da variaçãototal para animais F1 e Nelore, respectivamente. Esse componente contrastou animais de maiores G365com animais de maiores GND e G550, respectivamente, para animais F1 e Nelore.