Parâmetros fisiológicos de bovinos cruzados submetidos ao estresse calórico RESUMOCaracterizaram-se as respostas fisiológicas de termorregulação em conforto e estresse calórico de bovinos cruzados F 2 (½ Gir x ½ Holandês), machos e fêmeas, com idade entre 14 e 20 meses. Os animais foram alocados, em número de cinco, e submetidos ao conforto térmico (22°C a 70% de umidade relativa) por 12 horas e ao estresse calórico (42ºC e 60% de umidade relativa) durante seis horas, logo após o período de conforto, nas estações de verão e inverno, em câmara bioclimática. Nas duas etapas, foram registradas a temperatura retal (TR), a freqüência respiratória (FR) e a temperatura de superfície corporal (TSC) às 6 e 16 horas. Os animais apresentaram aumento da TR, da FR e da TSC no período de estresse calórico (P<0,05). O aumento da TR e FR foi mais acentuado no verão (P<0,05). A TSC não apresentou diferença entre as estações (P<0,05).Palavras-chave: bovino, estresse calórico, temperatura retal, freqüência respiratória, temperatura de superfície corporal ABSTRACTThe thermoregulation physiological responses in thermoneutrality and heat stress of crossbred calves (½Gir x ½Holstein), males and females, with age between 14 and 20 months were studied. The animals were submitted to thermoneutrality (22°C and 70% of relative humidity)

Este artigo foi recebido em 2/7/2007 e aprovado em 31/7/2008 Nutritional evaluation of pineapple industry by-product as additive on elephant grass silageABSTRACT -The present study aimed to determine de nutritional value of mixed elephant grass silages in increasing levels with dehydrated pineapple industry by-product (PAB). Five PAB levels (0.0, 3.5, 7.0, 10.5, and 14.0%) were tested with 20 male non-castrated sheep in a randomized experimental design of five treatments (PAB levels) and four replications per treatment (sheep). Intake and digestibility of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (CEL), hemicelulose (HCEL) and energy as well as nitrogen balance were determined. Linear increases on the DM, CP intake and digestible energy occurred as the PAB content increased in the silage. For every increase of 1% of PAB in the silage, increments of 16.17 g and 1.55 g of DM and CP intakes, respectively, were observed. The addition of PAB in the silage increased the DDM, DCP and DE intake. However, the nutrients digestibility remained unchanged.Mean values were 53.3%, 42.1%, 55.2% and 2.92 g/day for DM, CP, NDF and NB, respectively. NB was positive only with PAB in the rations. It is concluded that additions of PAB in the elephant grass silage up to a level of 14% in a natural basis increases the digestible nutrients intake.Key Words: ensilage, nutritional value, tropical grass IntroduçãoA estacionalidade na produção de forragem tem sido responsável, entre outros fatores, pela reduzida produtividade dos rebanhos, que, em conjunto com a freqüente variação dos preços dos grãos de cereais e dos suplementos protéicos utilizados na alimentação animal, tem despertado o interesse no aproveitamento de alimentos alternativos.Nesse contexto, os resíduos agroindustriais podem ser importantes na alimentação de ruminantes, principalmente em situações de baixa disponibilidade de forragem. O resíduo da indústria do processamento de abacaxi tem sido utilizado em algumas pesquisas em substituição a

This study evaluated the effect of coarse or fine grinding of three forms of corn on the performance of lactating cows. Six diets, fed as total mixed rations, were identical except for the corn portion of the diet. Corn treatments were dry shelled corn, high moisture ensiled ear corn, and high moisture ensiled shelled corn, either coarsely or finely ground. The experimental design was a 6 x 6 Latin square with 36 cows. Eighteen cows were assigned to the six different treatments and were fed once daily. Within this group of 18 cows, six had a ruminal cannula and were used to evaluate nutrient digestibilities and ruminal fermentation. The remaining 18 cows, six of which were ruminally cannulated, were similarly assigned, except they were fed twice daily. In the group fed once daily, milk production and composition were not affected by treatment. Starch digestibility was greater with the high moisture and with the finely ground corn treatments. In addition, the high moisture ensiled corn treatments had reduced ruminal ammonia concentrations. In the group that was fed twice daily, milk production and protein yield were greatest for the finely ground high moisture ensiled shelled corn treatment. Starch utilization was improved by fine grinding. Lower ruminal ammonia concentrations were obtained with the high moisture ensiled corn treatments, and there was a tendency for reduced ammonia concentration with fine grinding. Results indicate that high moisture ensiled corn as well as fine grinding improved nitrogen and starch utilization.

Taxa de sudação e parâmetros histológicos de bovinos submetidos ao estresse calórico

Parâmetros clínicos, hematológicos, bioquímicos e hormonais de bovinos submetidos ao estresse calórico [Clinical, hematological, biochemical, and hormonal

An indirect calorimetry system for rapid determination of CO 2 and CH 4 production and O 2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals.

-This study was conducted to evaluate the intake, apparent digestibility (AD), and degradability in situ of elephant grass (Pennisetum purpureum Schum) silages containing 0, 35.0, 70.0, 105.0, and 140.0 g kg -1 by-product from dried cashew apple (DCBP) (as fed basis). A completely randomized design with four replicates was adopted. For the study of degradability in situ, one adult male cattle was used in a completely randomized design with split plots. Intake and AD of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, and cellulose were evaluated, and the digestible energy (DE) and nitrogen balance (NB) of the silages were determined. The degradability in situ of DM, CP, and NDF was also determined. Addition of DCBP provided an increase in the intakes of DM, CP, NDF, and ADF. No effects of the levels of addition of DCBP were observed on the coefficients of AD of the silages. Regarding NB, positive values were only detected in the treatment with 105.0 g kg -1 DCBP. In the analysis of the degradability in situ, the incubation periods increased the rates of disappearance of DM, CP, and NDF. However, no effect of the levels of DCBP were observed on the effective degradability of DM. The by-product from dried cashew apple can be included at up to 140.0 g kg -1 in silages of elephant grass, but the high contents of acid detergent insoluble nitrogen may compromise the use and availability of nitrogen to the animals.

The objective of this study was to evaluate the in situ degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose of elephant grass (Pennisetum purpureum, Schum.) with increasing levels (0; 35.0; 70.0, 105.0, and 140.0 g kg -1 ) of dried pineapple (Ananas comosus, L.) byproduct (DPBP). The experimental silos consisted of plastic drums with 210 L capacity. After weighing and homogenizing the elephant grass with the DPBP, the material was inserted in the silos (126 kg silage, at a density of 600 kg m -3 ) and compressed. After 45 days of ensilage, silos were opened and samples of the silages were collected for the trial. The study of degradability in situ was conducted using a rumen-fistulated steer. The animal was fed with corn silage supplemented with 1 kg concentrate daily. Five levels of addition of the byproduct were tested, with three replicates and five times of incubation with an animal. The experimental design was completely randomized with split plots, in which the proportions of DPBP were the treatments (plots), the different silos were the replicates, and the incubation times were the subplots. The levels of inclusion of DPBP provided an increase (P<0.05) in disappearance of DM and CP and in the effective degradability of DM, NDF, ADF and hemicellulose. The dried pineapple byproduct is a potential alternative to be used as additive in the ensilage of elephant grass, as it provides an increase in the rumen degradability parameters. Key words: Agroindustrial waste. Digestibility. In situ degradation. Intake. Rumen.