Investigations into traditionally managed Djallonké‐sheep production in the humid and subhumid zones of Asante, Ghana III. Relationship between birth weight, preweaning growth, and postweaning growth of lambs*

Abstract

Summary Birth weight, which is subject to differences in prenatal nutrition, increased with parities to the fifth among the subhumid zone (SH = 1.89 kg) dams and to the sixth among the humid zone (H = 1.71 kg) dams. Seasonal influence did not significantly affect birth weights in either zone. Litter type had the greatest influence on birth weight, growth rate, and viability at 60 days of age, among lambs in both zones. The dual advantage of higher birth weight of lambs and higher postpartum weight of their dams, with the benefit of the maternal effect that supported optimal postnatal development lambs, resulted in higher body‐weight gain at 60 days of age at sixth parity (H = 6.17 kg; SH = 6.99 kg). In both zones, viability was optimum at the fifth parity (H=95.0%; SH = 95.6%). For all weight traits, single lambs (H = 7.73 kg; SH = 8.48 kg) were significantly (p < 0.05) and consistently superior to twin lambs (H = 6.68 kg; SH = 7.31 kg) at the natural weaning age of 105 days. At birth, female lambs were 6.4% behind male lambs in their subsequent growth up to natural weaning, even when the birth weight of both sexes was similar. In both zones, the viability showed an upward trend, with an increase in percentage of lambs weaned up to the fifth parity (H = 80.0%; SH = 90.1%) and a rapid decline after the sixth parity. The postpartum weight and higher parity, together with the postnatal maternal effect of dams' performance on growth in the first 60 days, influenced lambs' weaning weight at 105 days. There was no significant seasonal pattern of growth. At 210 days of age, the influence of litter type started to diminish. Differences in body weight due to sex also became relatively less important at this age. The ewes which had gained rapidly in weight appeared heavily pregnant, and with full udder, at 210 days of age. These findings confirm the importance of the transient nature of growth between 90 and 105 days of age. The physiologically mature weight is reached at higher parity, between the fifth and sixth, antibody weights of 20.93 and 23.59 kg for the humid and subhumid zone ewes, respectively. The mean liveweight considered to be a measure of physiological maturity was attained between 3.5 and 4.0 years of age. Résumé Etudes sur la production ovine traditionnelle dans la région humide et sub‐humide d'Asante (Ghana). III. Relations entre le poids de naissance et le développement du poids du corps avant et après le sevrage Le poids de naissance était fonction de l'influence d'alimentation prénatale variante. Il augmentait jusqu'au point du cinquième agnelage dans la zone sub‐humide (1,89 kg) et du sixième agnelage dans la zone humide (1,71 kg) montrant une dépendance directe du poids des brebis. Dans les deux zones climatiques, on n'a observé aucune influence saisonnière significative par rapport au poids de naissance. Le type de la portée (c.‐à‐d. portée individuelle ou multiple) avait l'influence la plus grande quant au poids, au développement du poids et au taux de survie des agneaux jusqu'au soixantième jour. ...

Comparison of non-linear growth models to describe the growth curve in West African Dwarf sheep

“…The lambs born in rainy season were heavier and grew faster than their counterparts from the dry season (Figure 2c). Similar seasonal influences have been found in tropical area (London and Weniger, 1995;Ebangi et al, 1996) and may be due to the variation of the physical environment that affect the availability and quality of forage during dry season, since the year-round grazing was the practice in Betecoucou farm. The lambs weight consistently increased with ewe parity (Figure 3a) as described in other studies (London and Weniger, 1995;Ebangi et al, 1996;Yapi-Gnaoré et al, 1997).…”

“…The shape of the growth curve showed that male ( Figure 2a) and single lambs ( Figure 2b) were heavier than female and twin lambs, respectively. The higher weight of male than female has been described in WAD sheep (London and Weniger, 1995;Ebangi et al, 1996;Gbangboche et al, 2006b) and could be attributed to the hormonal and physiological differences between sexes (Ebangi et al, 1996). The superiority of single lambs over Selected model: A is the predicted asymptotic weight at maturity (kg), B is the proportional difference between A and birth weight (kg) and k is the rate of maturating.…”

“…The observed minus predicted weight shows that the Brody model under predicted (Figure 1a) by 20.64 and 20.21 kg at 30 days and 60 days, respectively, and by 20.48 and 20.33 kg at 150 and 180 days weight, respectively. Inversely, the birth weight, 90 days and 120 days (Armbruster et al, 1991a and1991b;London and Weniger, 1995;Yapi-Gnaoré et al, 1997); 6.02 kg at 60 days of age (London and Weniger, 1995); 9.1 kg at 80 days of age (YapiGnaoré et al, 1997); 6.99 to 12.7 kg at 90 days of age (Poivey et al, 1986;Armbruster et al, 1991b;London and Weniger, 1995;Yapi-Gnaoré et al, 1997); 8.71 kg at 120 days of age (Fall et al, 1982); 15.1 kg at 180 days of age (Poivey et al, 1986). Gbangboche et al (2006a) reported the mean body weight of 27.5 6 2.4 kg at 1.7 years, and London and Weniger (1995), 20.9 and 23.6 kg at 3.5 and 4 years of age.…”

“…Gbangboche et al (2006a) reported the mean body weight of 27.5 6 2.4 kg at 1.7 years, and London and Weniger (1995), 20.9 and 23.6 kg at 3.5 and 4 years of age. A minimum dam body weight of 11.0 kg was required for mating (London and Weniger, 1995). The fact that difference in management practices, levels of genetic improvement and many unknown factors affected WAD sheep may be explained by the variation in live body weight reported by many authors.…”

“…In Benin, the WAD sheep is raised exclusively for meat and was estimated at 700 000 (Faostat, 2005), and play an important economical, social and cultural roles. For this purpose in West and Central Africa, the genetic and non-genetic effects on the growth performance of WAD sheep had become an attractive study in last decades to improve overall productivity (London and Weniger, 1995;Yapi-Gnaoré et al, 1997;Gbangboche et al, 2006a and2006b). However, the advantage of growth models such as Logistic and Gompertz (Renne et al, 2003;Lambe et al, 2006), Von Bertalanffy (Topal et al, 2004) and Brody model (Bathaei and Leroy, 1998), which give an explanation of what is biologically occurring during the growth phase of an animal, and their importance on breeding program (Varona et al, 1997;Lewis and Brotherstone, 2002) were unknown in WAD sheep.…”