Direct genetic and maternal effects affecting litter size, birth weight and pre-weaning losses in Creole goats of Guadeloupe

Abstract

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.

Prolificidade de caprinos mestiços leiteiros no semiárido nordestino

“…Santos et al (1998), utilizando informações de prolificidade deste mesmo rebanho, porém empregando a metodologia de quadrados mínimos ordinários, encontraram efeito significativo apenas da ordem de parto. Silva & Araújo (2000), estudando um rebanho de cabras mestiças no Brasil, porém utilizando a metodologia de quadrados mínimos, verificaram efeito significativo apenas para o ano de parição; já os efeitos de grupo genético, ordem de parto e peso da mãe no parto não foram importantes fontes de variação.…”

“…Efeitos significativos da ordem do parto sobre a prolificidade foram encontrados por Santos et al (1998). Diferindo dos resultados obtidos neste estudo, Amoah et al (1996) e Silva & Mello (1996) relataram que este efeito não foi importante fonte de variação sobre a prolificidade.…”

“…A literatura nacional ainda é incipiente no que diz respeito a estudos de algumas características reprodutivas de caprinos. Os escassos artigos verificados na literatura nacional (Silva & Mello, 1996;e Santos et al, 1998) buscaram avaliar a influência de alguns efeitos do ambiente sobre a referida característica e empregaram modelos que pressupõem distribuição normal, quando, na prática, isso não ocorre, uma vez que esta tem distribuição discreta.…”

Improvement of rearing goats in Bali Province, Indonesia

“…Published data on litter size that was reported from 0.99 to 2.34 in different genotypes of does with information about the type of birth, sex of kid, and parity of does under different ecological and management conditions is summarized in (1996) In prolific species, the high level of competition between foetuses had a meaningful effect on developmental capacity, survival rate of the foetus and individual growth rate of the animals born in the litter and during the preweaning period (Nowak 1996;Perez-Razo et al 1998;Mellado et al 2000a;Nowak et al 2000;Simsek & Bayraktar 2006;Simsek et al 2007;Mahmilia & Elieser 2008). In other words, higher litter size was correlated with lower birth weight and higher losses of young in goats during the first few days of life (Ruvuna et al 1991;Menendez-Buxadera et al 2003;Menendez-Buxadera et al 2004). Stabilizing the variability of the size of the litter or even decreasing litter size increased the birth weight and thus potentially decreased the loss of kids.…”

“…Eventually this improved the productivity of the dams (Menendez-Buxadera et al 2003). Published data on birth weights was reported from 1.7 to 5.0 kg in different genotypes of goats with information about the type of birth, sex of kid, and body condition score of does under different ecological and management conditions is summarized in Table 2.12.…”