Animal management for breeding and marketing can be improved by precise measurement of desirable traits. Live animal body composition analysis facilitates the selection of animals that are best suited for the intended purpose. This study was designed to assess the accuracy of bioelectrical impedance analysis (BIA) predicted live body tissue composition, as a proxy for the estimation of carcass quality in Barbados Black Belly lambs. Thirty-four Barbados Black Belly lambs were placed on an 8-week feeding regime and then slaughtered. A randomized experimental design was used to allocate diets to animals, which had been stratified into eight groups by initial live weight. The lambs were fed a basal diet of Brachiaria arrecta fresh forage ad libitum and subjected to one of four diets; NS-non-supplemented diet, TG-Trichantera gigantea-supplemented, C100-concentrate supplemented for maintenance, and C400-concentrate supplemented for growth. Diets NS, TG, C100, and C400 had 7, 9, 11, and 7 animals, respectively. The average age and weight at the time of slaughter were 206 days and 23.7 kg, respectively. A 4-terminal impedance analyzer (RJL Systems®) was used to generate BIA data from live animals immediately before slaughter. The chilled carcasses were then subject to chemical analysis for crude fat, crude protein, and dry matter. Live animal and carcass traits predicted by BIA included fat and fat-free mass, crude fat, crude protein, protein to fat ratio, and tissue distribution. Regression equations were developed from BIA data obtained from the live animal to predict all carcass composition traits measured. Bioelectrical impedance analysis generated favorable results as a practical application to carcass composition evaluation in live tropical hair sheep.

Pasture based systems are considered to be more sustainable than those that depend on high imported concentrate feedstuff. However, it is a common practice in the Caribbean for animals to be kept at pasture without proper shade and water because the farmers believe that the animals are adapted. The thermoregulation of Barbados Blackbelly (BB) and West African (WA) type ewes and seasonal effects on pre-weaning performance of lambs from ewes managed at pasture at the Blenheim Sheep Multiplication and Research Project were studied. Rectal temperature (RT), respiration rate (RR), and infrared thermography were used to assess the thermoregulation of ewes. The temperatures and respirations per/min was taken at 8:00 in the morning before they go out to pasture and at 3:00 when they return. RT and RR data were subjected to repeated measure analysis. Both types showed no significant difference (P . 0.05) with regards to their thermoregulatory processes, with the exception of RT which was higher (P , 0.001) for WA in the afternoon. Rectal temperature for BB and WA was 38.34 and 38.418C in the morning whereas it was 39.14 and 39.458C in the afternoon, respectively. Barbados Blackbelly showed a 2.8 fold increase in RR when they returned from pasture compared to 3.0 fold increase for WA ewes. Heat was lost in the facial area and underbelly and between the legs in the morning and when they returned from pastures in the afternoon heat lost was observed throughout the entire body surface including facial areas. The lamb pre-weaning performance was analysed for the period of 1999 to 2004. Birth weight, weaning weight and pre-weaning growth weight of lambs were analysed according to the GLM procedure. The fixed effect in the model included year of birth, season of birth, season of conception, birth type, sex and breed. Significant differences (P , 0.05) were observed between years, sex and birth type for the parameters birth weights, pre-weaning average daily gain and weaning weights. There were no significant differences (P . 0.05) between WA and BB for birth weights (2.78 vs. 2.71 kg), weaning weights (12.26 vs. 11.69 kg) or preweaning growth rates (124 vs. 115 g d 21 ), respectively. Season of conception significantly (P , 0.05) influenced birth weights but not preweaning average daily gain or weaning weights (P , 0.05). Season of birth effect was significant (P , 0.05) for birth weights and pre-wean average daily weight gain but not weaning weights (P . 0.05). Temperature humidity index (THI) was significantly (P , 0.05) higher in the wet compared to the dry season 79.60 (60.13) vs 77.98 (60.24), respectively. Litter size distribution by season indicated that there was only a 4.1% reduction in litter size in the dry season. In the current study birth weight of lambs conceived in the dry season was 2.5% lighter than lambs conceived in the wet season (P , 0.05) and lambs born in the dry season were heavier than those born in the wet season (P , 0.05). It is well known that heat stress in early and late gestation can cause a decr...