Produção e conforto térmico de bovinos da raça Nelore terminados em sistemas integrados de produção agropecuária / Production and thermal comfort of Nellore beef cattle finished in integrated crop-livestock systems

O objetivo deste trabalho foi avaliar a pastagem, o desempenho, o conforto térmico e os parâmetros hematológicos de bovinos Nelore na fase de terminação em sistemas integrados de produção agropecuária com duas densidades de árvores (ILPF-1L= 196 árvores ha-1 e ILPF-3L=448 árvores ha-1) e em pleno sol (ILP). Foram avaliados a massa e a composição morfológica da forragem, o ganho médio diário, o ganho de peso por área e a taxa de lotação no verão e no outono, bem como as variáveis climáticas dos sistemas em três horários e parâmetros hematológicos dos animais (n=60). A massa de forragem foi superior no tratamento ILP e no verão (P<0,05). Porém, a redução da massa de forragem nos sistemas ILPFs não interferiu no desempenho dos animais (P>0,05). A temperatura ambiente, a temperatura do globo e o índice de temperatura e umidade foram melhores nos tratamentos com sombreamento e no período da manhã, proporcionando maior conforto aos animais, sendo ainda confirmado pelo menor volume globular dos bovinos em ILP (P<0,05). Conclui-se que os sistemas com componente arbóreo diminuem a massa de forragem, mas essa redução não altera o desempenho dos animais na fase de terminação. Além disso, os sistemas ILPFs melhoram o conforto térmico, entretanto essa melhora não foi suficiente para favorecer o desempenho.(AU)

The objective of this work was to evaluate pasture, performace, thermal comfort, and haematological parameters of Nellore cattle in the finishing phase in integrated crop-livestock systems with two tree densities (ICLF-1L= 196 ha -1 trees and ICLF-3L= 448 ha -1 trees) and in full sun (ICL). The forage mass morphological composition of the pasture average daily gain, weight gain per area, stocking rate of the animals were evaluated in summer and autumn, and the climatic variables of systems we evaluated at three different times, and haematological parameters of the animals (n= 60). The forage mass was higher in the ICL treatment and summer (P<0.05). However, the reduction of the forage mass in the ILPFs systems did not interfere with the performance of the animals (P>0.05). Ambient temperature, globe temperature and temperature and humidity index were better in shade treatments and in the morning, providing greater comfort to the animals, and was also confirmed by the lower globular volume of the bovines in ICL (P<0.05). It is concluded that the systems with trees reduce the forage mass but this reduction does not alter the animals' performance in the finishing phase. In addition, ICLFs improve the thermal comfort of the animals, however, this improvement was not enough to favor their performance.(AU)

Estimação de parâmetros genéticos para características de pesos e pesos metabólicos na desmama e pós-desmama em bovinos Brahman / Estimation of genetic parameters for weaning weights and metabolic weights characteristics and post weaning in Brahman cattle

Objetivou-se estimar herdabilidades e correlações de características ponderais com 36.505 animais, da Associação Brasileira de Criadores Zebu. O modelo incluiu efeito genético direto, materno, ambiente permanente, residual - aleatórios e efeitos de grupos contemporâneos - fixos. Os parâmetros foram estimados pelo método de máxima verossimilhança restrita (REML), utilizando-se software Wombat. Os resultados das herdabilidades variaram de 0,20 a 0,25 peso à desmama e ao sobreano; 0,16 a 0,20 peso metabólico não ajustado e ajustado à desmama, 0,21 a 0,25 peso metabólico ajustado à desmama e metabólico ajustado ao sobreano. As correlações genéticas entre peso à desmama e peso metabólico não ajustado à desmama, peso à desmama e peso metabólico ajustado à desmama são, respectivamente 0,76 e 1,00. A correlação genética entre peso ao sobreano e metabólico ao sobreano não ajustado, peso ao sobreano com metabólico sobreano ajustado foram 0,97 e 1,00. Correlação genética entre peso à desmama e ao sobreano foi 0,72, peso metabólico não ajustado à desmama e metabólico não ajustado ao sobreano 0,54, peso metabólico ajustado à desmama e metabólico ajustado ao sobreano foi 0,71. Correlações genéticas entre peso à desmama e metabólico ajustado à desmama e peso ano com metabólico ano ajustado foram 1,00 e 1,00. Portanto, utilização de peso metabólico sem ajuste de idade pode viesar estimativas de parâmetros genéticos.(AU)

The objective of this study was to estimate heritability and correlations of 36,505 animals, belonging to the Brazilian Association of Zebu Breeders. They were estimated by Restricted Maximum Likelihood method (REML) using Wombat software. The model included the direct additive genetic effect, maternal, permanent maternal environment and residual as random and fixed effects of contemporary group. The results of heritability ranged from 0,20 to 0,25 for weaning weight and yearling; 0,16 to 0,20 for real metabolic weaning, 0,21 to 0,25 for metabolic adjusted weight at weaning and yearling metabolic adjusted. The genetic correlations between weaning weight with metabolic real, weaning weight adjusted with metabolic are respectively 0,76 and 1,00. The genetic correlation between yearling weight and metabolic real, yearling weight adjusted metabolic were 0,97 and 1,00. Genetic correlations between weaning weight and yearling was 0,72, real metabolic weight at weaning and yearling real metabolic was 0,54, adjusted metabolic weight at weaning and yearling metabolic adjusted was 0,71. Genetic correlations between weight at weaning and adjusted metabolic and weight-adjusted metabolic year were 1,00 and 1,00. Therefore, the use of metabolic weight without age adjustment can warn the estimates.(AU)

Padrão de deslocamento de bovinos Nelore em sistemas integrados de produção agropecuária / Displacement patterns of Nellore cattle in integrated crop livestock system

The objective of this study was to characterize the displacement patterns of Nellore cattle in areas of crop livestock and crop livestock forest integration systems with density of 196 and 448 eucalyptus ha-1. Paddock maps were drawn from satellite images of the experimental area. In each evaluated system there was one trained observer, that on the paddock map recorded the place the animals stayed every 10 minutes. The exploration of the area by the animals was observed for 12 hours, starting at 6 a.m. and ending at 6 p.m. The displacement of the animals in the ILP system during the evaluation was bigger than the ILPFs systems, resulting in greater exploration of the area, this fact was due the presence of trees that, for the animals resembled fences, limiting the exploration of the paddock in ILPFs. In the ILPF with higher density of trees, this behavior was more evident. In the period from 10:10 a.m. to 14:00 p.m. the displacement of the animals was decrease by the high temperatures in all systems, although it was more effective in the ILP system. It is concluded that the displacement of cattle is influenced by the presence and density of arboreal component integrated crop livestock system.(AU)

Supplementation with sunflower seeds in beef cattle did not impact on oocyte and in vitro embryo production.

Supplementation with compounds rich in linoleic acid, including sunflower seed supplementation, promotes increase in conception rates in cows. We aimed to evaluate whether the sunflower seed (linoleic acid source) supplementation in beef donor females alters the plasma concentrations of cholesterol, triglycerides, HDL and LDL, increases the number and quality of oocytes, increases the cleavage rates and determines an improvement in number and quality of in vitro produced blastocysts. Thus, Nelore females were divided into two groups of 15 animals to receive supplementation with or without sunflower seed for 57 days. Females underwent follicular aspiration and the oocytes were subjected to in vitro embryo production. There was no difference (p > .1) between control group and group supplemented with sunflower seed on the number of displayed follicles; number of aspired oocytes; recovery rate; cleavage rate; number of embryos; number of blastocysts; embryos number of grades I and II; plasma concentrations of total cholesterol, triglycerides; HDL and LDL. Therefore, sunflower seed supplementation in oocyte donors did not increase the number and quality of oocytes, cleavage rates and the number and quality of blastocysts produced in vitro.

Performance, carcass and meat characteristics of two cattle categories finished on pasture during the dry season with supplementation in different forage allowance / Desempenho, características da carcaça e carne de duas categorias de bovinos de corte terminados em pastagem durante a estação seca com suplementação em diferentes ofertas de forragem

The objective this paper was to evaluate the effect of two categories of beef finished in pasture with supplementation with two herbage allowance on performance, carcass and meat characteristics. Thirty-six Guzera cattle were used, 18 steers and 18 heifers with an initial age of 20 months. There was significant difference in daily weight gain for animal category and the herbage allowance, which were higher in males and animals submitted to high herbage allowance. Steers showed higher final weight, carcass weight and forequarter yield compared with the heifers, although the hindquarter yield was higher in the heifers, however the herbage allowance did not influence these characteristics. There were not statistical differences for carcass yield, ribeye area, backfat thickness and marbling score for the animal categories and herbage allowance. The meat chemical composition of the steers did not differ of the heifers, however, the animals submitted to high herbage allowance was increase in ether extract and pH, decrease in protein percentage. It was concluded that the animal category and the herbage allowance changed the animal performance, improving performance in males and cattle submitted to high herbage allowance.(AU)

O objetivo do presente trabalho foi avaliar o efeito de duas categorias de bovinos terminados em pastagem com suplementação em duas ofertas de forragem no desempenho, na qualidade da carcaça e da carne. Foram utilizados 36 bovinos Guzerá, 18 novilhos e 18 novilhas, com idade inicial de 20 meses de idade. Observou-se diferença significativa no ganho de peso diário para categoria animal e ofertas de forragem, que foram superiores nos machos e nos animais submetidos à oferta alta de forragem. Os novilhos apresentaram maior peso final, peso de carcaça e rendimento de dianteiro em comparação com as novilhas, embora o rendimento do traseiro tenha sido maior para as novilhas, entretanto as ofertas de forragem não influenciaram essas características. Não houve diferenças estatísticas para rendimento de carcaça, área de olho de lombo, espessura de gordura subcutânea e marmorização para categorias de animais e ofertas de forragem. Quanto à composição química, a carne de novilhos não diferiu das novilhas. Os animais submetidos à alta oferta de forragem tiveram aumento no extrato etéreo e pH, redução na porcentagem de proteína. Conclui-se que a categoria animal e os níveis de forragem alteram o desempenho animal, melhorando, assim, o desempenho nos machos e nos bovinos submetidos à alta oferta de forragem.(AU)