Morphometric measurements of calves of beef cattle from different genetic groups up to one year of age

Heterosis plays an important role on yield and profitability of beef production systems. This study evaluates the morphometrics of purebred Nellore (N) and Charolais (C) animals and of the second (G2) and third (G3) generations of their alternating crosses, regarding the effects of genetic group and heterosis from birth to 365 days of age. The experiment comprised 159 calves (C = 29, N = 22, G2 - 3/4C 1/4N = 21, 3/4N 1/4C = 9, G3-5/8C 3/8N = 44 and 5/8N 3/8C = 34). The foreshank girth (FG), thoracic girth (TG), body length (BL), and hip height (HH) were measured after birth, and at 63, 210, and 365 days of age, and the total increases were calculated. The Charolais animals had greater FG, TG, and BL values than Nellore, while the latter had greater HH. For the offspring generations, the predominance of Charolais genes in the genotypes resulted in greater measurements for FG and TG in G2, whereas the predominance of Nellore genes resulted in higher HH values in both generations. The crossbred animals had greater values for all measurements than the purebreds, with more significant differences in FG, TG, and BL compared to Nellore purebreds and in HH compared to Charolais. Charolais animals show higher values for muscularity; while, Nellore animals are taller. Crossbred animals show greater development compared to purebreds, indicating a significant effect of heterosis.

Implications of growth rates and compensatory growth on puberty attainment in Nellore heifers.

This study investigated the effects of growth rates and compensatory growth on puberty attainment in Nellore heifers. Nellore heifers (n = 120), weaned at 8 ± 0.75 mo of age, were blocked by sire and BW (180 ± 8.6 kg) and assigned randomly to receive 1 of 4 treatments over a 10-mo period. Treatments included ad libitum feeding (high gain, HG), feed intake to gain 0.6 kg/d (medium gain, MG), restricted feeding (0.2 kg/d) for 4 mo followed by ad libitum feeding for 6 mo (compensatory gain, CG), and alternating periods of ad libitum and restricted feeding for 2 mo each throughout the trial (alternated CG, ACG). Puberty was assessed weekly by transrectal ultrasonography. Blood samples were collected at 8, 11, and 18 mo of age and at puberty to determine circulating concentrations of leptin. At 18 mo of age, nonpubertal heifers were treated with a puberty induction protocol using an intravaginal progestin device. There was no treatment effect (P = 0.17) on the percentage of heifers pubertal by 18 mo of age (HG: 66, MG: 40, CG: 58, and ACG: 52%), BW at puberty, and age at puberty. However, HG heifers had higher ADG (P < 0.01), dry matter intake (P < 0.01), and leptin concentrations (P = 0.03) than heifers from other groups. The response to the puberty induction protocol was similar (P = 0.90) among treatments. Regarding sire effects (genetic effects), there was an effect (P = 0.03) on the percentage of heifers pubertal by 18 mo of age and a tendency (P = 0.07) of sire effect in response to the puberty induction protocol. Compensatory growth appears to be an effective managerial approach to decrease feeding costs and stimulate puberty in Nellore heifers.

Dietary addition of curcumin favors weight gain and has antioxidant, anti-inflammatory and anticoccidial action in dairy calves / La adición de curcumina en la dieta de los terneros lecheros favorece el aumento de peso y tiene acción antioxidante, antiinflamatoria y anticoccidial / A adição de curcumina na dieta dos bezerros leiteiros favorece o aumento de peso e tem ação antioxidante, anti-inflamatória e anticoccidiostática

Abstract Background: Curcumin has been used as an additive in the diet of animals in recent years due to the potent medicinal properties of this molecule. Objective: To evaluate whether the addition of curcumin to the diet of calves at different phases (pre- and post-weaning) has a positive effect on metabolic profile, performance, and anti-coccidian action. Methods: Thirty-three Holstein calves were selected at various phases of development: Experiment 1 (E1: n=10) 18±7 (pre-weaning), Experiment 2 (E2: n=11) 64±4 (pre-weaning) and Experiment 3 (E3: n=12) 95±8 (post-weaning) days of life. The calves were separated in three groups according to their phase of development. In each experiment, animals were divided into two sub-groups: control and curcumin. The curcumin groups received 200 mg of additive per animal/day either in milk (pre-weaning) or concentrate (post-weaning). Fecal collections were performed on days 0, 10 and 15 of the experiment to count Eimeria oocysts per gram of feces and to perform fecal score analysis. Complete blood counts, oxidant and antioxidant profiles, protein metabolism markers, lipid levels, glucose levels, and animal weights were measured. Analyses of digestibility and composition of the diet used in Experiment 3 (post-weaning) were also performed. Results: Independent of phase, animals that received curcumin had greater weight gain on days 0 to 15 (E1, E2 and E3 p=0.04, 0.001 and 0.001, respectively), probably due to the increased digestibility of hay and concentrate at 72h (p=0.03 and 0.02, respectively). The supplemented calves had lower level of oxidants (thiobarbituric acid reactive substances -TBARS- and reactive oxygen species -ROS-), indicating that free radical levels in serum and lipid peroxidation were lower. This was probably due to increased enzymatic antioxidants gluthatione S-transferase (E1, E2 and E3 p=0.001, 0.001 and 0.02, respectively), catalase (E1 p=0.001) and superoxide dismutase (E3 p=0.001) in treated animals at day 15. Furthermore, calves receiving curcumin had lower numeric number of Eimeria infection during the experimental period, and the difference was significant in day 15 (E1 and E2 p=0.02, and 0.001, respectively). Conclusion: Curcumin supplementation to dairy calves has coccidiostatic potential, favoring weight gain.

Resumen Antecedentes: Curcumina ha sido utilizada como aditivo en la dieta de animales en los últimos años, debido a las potentes propiedades medicinales de esa molécula. Objetivo: Evaluar si la adición de curcumina en la alimentación de terneras en diferentes fases (pre y post-destete) presenta efecto positivo sobre el perfil metabólico, desempeño de los animales, y acción anti-coccidial. Métodos: Se seleccionaron 33 terneros Holstein en varias etapas de desarrollo: Experimento 1 (E1: n=10) 18±7 (pre-destete), Experimento 2 (E2: n=11) 64±4 (pre-destete) y Experimento 3 (E3: n=12) 95±8 (post-destete) días de vida. Para todos los experimentos, el período experimental fue de 15 días. Los animales se dividieron en dos grupos: control y tratados con curcumina. Los grupos con curcumina recibieron una dosis de 200 mg del aditivo por animal/día en la leche (pre-destete) o en el concentrado (post-destete). Las colectas de heces y sangre fueron realizadas en los días 0, 10 y 15 para conteo de ooquistes de Eimeria por gramo de heces y análisis de puntaje fecal. Se realizó hemograma, perfil oxidante y antioxidante, metabolismo proteico, lipídico, glucosa sanguínea y pesaje de los animales. También se realizó análisis de digestibilidad de la dieta total para los animales del Experimento 3 (post-destete). Resultados: Encontramos que, independientemente de la fase, los animales que recibieron curcumina tuvieron una mayor ganancia de peso en los días 0 a 15 (E1, E2 y E3, p=0,04, 0,001 y 0,001, respectivamente), probablemente debido al aumento de la digestibilidad del heno y concentrado a las 72 h (p=0,03 y 0,02, respectivamente). En los terneros suplementados observamos un nivel más bajo de oxidantes (oxidantes (sustancias reactivas al ácido tiobarbitúrico y especies reactivas de oxígeno); es decir, los niveles séricos de radicales libres y la peroxidación lipídica fueron más bajos. Esto se debió, probablemente, a los antioxidantes enzimáticos glutatión S-transferasa (E1, E2 y E3 p=0,001, 0,001 y 0,02 respectivamente), catalasa (E1, p=0,001) y superóxido dismutasa (E3, p=0,001) que aumentaron en los animales tratados al día 15. Además, los terneros que recibieron curcumina tuvieron niveles más bajos de infección por Eimeria durante el período experimental y fueron significativos en el día 15 (E1 y E2, p=0,02 y 0,001, respectivamente). Conclusión: La suplementación con curcumina tiene potencial coccidiostático y favorece la ganancia de peso en terneros Holstein.

Resumo Antecedentes: Curcumina tem sido usado como aditivo na dieta de animais nos últimos anos, devido as propriedades medicinais potente dessa molécula. Objetivo: Avaliar se a adição de curcumina na alimentação de bezerras em diferentes fases (pré e pós-desmame) apresenta efeito positivo sobre perfil metabólico, desempenho e ação anti-coccidéo. Métodos: Para isso, 33 bezerros holandeses foram selecionados em vários estágios de desenvolvimento: Experimento 1 (E1: n=10) 18±7 (pré-desmame), Experimento 2 (E2: n=11) 64±4 (pré-desmame) e Experimento 3 (E3: n=12) 95±8 (pós-desmame) dias de vida. Para todos os experimentos o período experimental foi de 15 dias, assim como foram delineados com dois grupos: controle e tratados com curcumina. Os grupos de curcumina receberam 200 mg do aditivo por animal/dia no leite (pré-desmame) ou em concentrado (pós-desmame). Coletas de fezes e sangue foram realizadas nos dias 0, 10 e 15 de experimento para contagem de oocistos de Eimeria por grama de fezes e análise de escore fecal. Do sangue colhido foram realizados: hemograma, perfil oxidante e antioxidante, metabolismo proteico, lipídico, glicose, além da pesagem dos animais. Também foi realizado análise de digestibilidade da dieta total ofertada aos animais do Experimento 3 (pós-desmame). Resultados: Independentemente da fase, os animais que receberam curcumina tiveram maior ganho de peso do dia 0 a 15 (E1, E2 e E3, p=0,04, 0,001 e 0,001, respectivamente), provavelmente devido ao aumento da digestibilidade ao feno e concentrado após 72 h (p=0,03 e 0,02, respectivamente). Nos bezerros suplementados, observou-se menor nível de oxidantes (substâncias reativas ao ácido tiobarbitúrico e espécies reativas de oxigênio), ou seja, os níveis séricos de radicais livres e a peroxidação lipídica foram menores. Isto foi provavelmente devido a antioxidantes enzimáticos glutationa S-transferase (E1, E2 e E3, p=0,001, 0,001 e 0,02, respectivamente), catalase (E1, p=0,001) e superóxido dismutase (E3, p=0,001) aumentando nestes animais tratados no dia 15. Além disso, bezerros recebendo curcumina tiveram menores níveis de infecção por Eimeria durante o período experimental e significativos no dia 15 (E1 e E2, p=0,02 e 0,001, respectivamente). Conclusão: A suplementação de curcumina aumenta o potencial coccidiostático e favorece o ganho de peso.

Parametrization of the Davis Growth Model using data of crossbred Zebu cattle

The system of differential equations proposed by Oltjen et al. [1986, named Davis Growth Model (DGM)] to represent cattle growth has been parameterized with data from Bos taurus (British) and Bos indicus (Nellore) breeds. The DGM has been successfully used for simulation and decision support in the United States. However, the effect of about 30 years of genetic improvement and the use of different breeds may affect the model parameter values, which also may need to be re-estimated for crossbred animals. The aim of this study was to estimate parameter values and confidence intervals for the DGM with growth and body composition data from Zebu crossbred animals. Confidence intervals and asymptotic distribution were generated through nonparametric bootstrap with data from a field experiment conducted in Brazil. The parameters showed normal probability distribution for most scenarios. The rate constant for deoxyribonucleic acid (DNA) synthesis had a minimum increase of 156 % and the maximum of 389 %, compared to the original values and the maintenance requirement had a minimum increase of 126 % and maximum of 160 % compared to the original values. Lower limits of 95 % confidence intervals for the parameters related to maintenance and protein accretion rates were higher than the original estimates of the DGM, evidencing genetic differences of the Zebu crossbred animals in relation to the original DGM parameters.(AU)

Parametrization of the Davis Growth Model using data of crossbred Zebu cattle

The system of differential equations proposed by Oltjen et al. [1986, named Davis Growth Model (DGM)] to represent cattle growth has been parameterized with data from Bos taurus (British) and Bos indicus (Nellore) breeds. The DGM has been successfully used for simulation and decision support in the United States. However, the effect of about 30 years of genetic improvement and the use of different breeds may affect the model parameter values, which also may need to be re-estimated for crossbred animals. The aim of this study was to estimate parameter values and confidence intervals for the DGM with growth and body composition data from Zebu crossbred animals. Confidence intervals and asymptotic distribution were generated through nonparametric bootstrap with data from a field experiment conducted in Brazil. The parameters showed normal probability distribution for most scenarios. The rate constant for deoxyribonucleic acid (DNA) synthesis had a minimum increase of 156 % and the maximum of 389 %, compared to the original values and the maintenance requirement had a minimum increase of 126 % and maximum of 160 % compared to the original values. Lower limits of 95 % confidence intervals for the parameters related to maintenance and protein accretion rates were higher than the original estimates of the DGM, evidencing genetic differences of the Zebu crossbred animals in relation to the original DGM parameters.