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The litter size (LS), or its equivalent the number of kids born in the litter (NB), of Creole goats in Guadeloupe was studied by two procedures. The first approach considered LS as a single trait and as a characteristic of the mother of the litter, and was studied by an univariate animal model (UAM). The second procedure treated NB, the individual birth weight (BW) and loss of kids (LK) as traits belonging to the animals born in the litter and their dam, in a multitrait animal model (MAM). The heritability for genetic direct effect (h2a) for LS estimated by UAM (0·14) was 40% lower than the corresponding value for NB estimated by MAM. The most appropriate of the 6 MAMs tested estimated heritabilities (h2a) of 0·24, 0·22 and 0·17 for NB, BW and LK, respectively, while maternal effects (h2m) were 0·20, 0·24 and 0·09 for the same characters. The genetic correlations between direct and maternal effects (ram) were negative –0·611 and –0·725 for NB and LK, respectively, and not significantly different from zero for BW. This study explored the possibility of using the information on NB, BW and LK recorded in each animal born in the litter in order to analyse the genetic variability of these traits.

This study aimed to compare the growth performances and carcass characteristics of tropical-breed steers reared in 2 contrasted feeding systems (indoor vs. pasture) and slaughtered at different ages (early vs. late). A total of 309 Creole steers (growing at an initial BW of 173 ± 3 kg and an initial age of 252 ± 4 d) were used over a continuous 12-yr study. Indoor steers were housed in a cattle shed, fed fresh-cut grass plus concentrate, and slaughtered at 14.5 or 17.1 ± 0.1 mo of age. Pasture steers were pasture grazed without supplemental feed, and slaughtered at 17.6 and 21.2 ± 0.1 mo of age. Indoor-fed steers had a greater ADG (786 vs. 517 ± 29 g•d(-1); P < 0.0001) and more carcass fat (164 vs. 145 ± 4.5 g•kg(-1); P = 0.001) than pasture-fed steers. Late-slaughtered steers had decreased ADG (630 vs. 673 ± 27 g•d(-1); P = 0.001) but greater dressing percentages (hot dressing percentage = 55.7 vs. 54.7 ± 0.34%; chilled dressing percentage = 54.5 vs. 53.4 ± 0.34%; P < 0.0001) than early-slaughtered steers. The interaction between feeding system and slaughter age was significant for carcass tissue composition. Whole-carcass muscle content was greater in late-slaughtered steers than early-slaughtered steers, especially in pasture-fed steers (720 vs. 698 ± 6.0 g•kg(-1); P < 0.0001), but less so in indoor-fed steers (707 vs. 700 ± 5.9 g•kg(-1); P = 0.046). Furthermore, increasing slaughter age had no effect on carcass fat in indoor-fed steers (162 vs. 166 ± 4.8 g•kg(-1); P = 0.342), but decreased carcass fat in pasture-fed steers (150 vs. 140 ± 5.0 g•kg(-1); P = 0.014). The results showed that slaughter age and feeding system are 2 major factors that independently affect most of the growth and carcass traits of tropical-breed steers but jointly influence tissue deposition. Our study found that in tropical-breed steers that are grazing, late slaughtering grazing steers increased carcass muscle content without extra fat, thus yielding a carcass quality better suited to consumer choices.

RésuméCette étude présente une synthèse des travaux menés sur l'évaluation des performances zootechniques des caprins Créoles à viande de Guadeloupe. Ce génotype rustique, de petit format, présente de grandes qualités reproductives et maternelles avec 90% de fertilité, 225% de prolificité et une viabilité naissance-sevrage de 78%. Les performances post-sevrage varient du simple au double selon les conditions d'élevage. Une grande souplesse d'exploitation associée à de fortes capacités productives, ainsi qu'à un potentiel d'adaptation, expliquent le succès de cet élevage aux Antilles. La chèvre Créole peut être sélectionnée sur ses performances d'élevage, de croissance et de résistance au parasitisme gastro-intestinal ou encore peut être valorisée comme souche maternelle pour des croisements possibles.

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