Effect of crossbreeding European sheep breeds with Awassi sheep on growth efficiency of lambs in Jordan (original) (raw)

2010, Agricultura Tropica et Subtropica

The objective of this study was to evaluate the effect of crossbreeding on body weight and growth ef¿ ciency of lambs from birth to weaning. The study was conducted on the Awassi sheep À ock and their crossbreds with Charollais and Romanov breeds maintained at the Agriculture Centre for Research and Production at JUST Irbid. In 2004, 2005 and 2006 live weight was determined in 420 lambs (95 Awassi, 158 Charollais x Awassi F 1 crossbred and 167 Romanov × Awassi F1 crossbred) at birth and subsequently every fortnight until weaning. Average live weights of lambs at birth,15, 30, 45 and 60 days of age were 4.18 ± 1.13 kg, 8.85 ± 2.12 kg, 12.20 ± 2.80 kg, 15.70 ± 3.50 kg and 19.25 ± 4.60 kg, respectively. ADG of lambs from birth until weaning was 255 ± 0.10 g. Genotype of lambs and litter size affected ADG, live weight of lambs at birth, 15, 30, 45 and 60 days signi¿ cantly (P 0.001). Investigations of the effect of sex on live weight of lambs at birth and at 60 days showed that the differences between males and females were statistically signi¿ cant (P 0.001). Differences in ADG and live weight at 15, 30 and 45 days according to dam age were also signi¿ cant (P 0.001). Similarly, the effect of dam weight at mating and at lambing on ADG, live weight of lambs at 15, 30, 45 and 60 days of age and until weaning were con¿ rmed (P 0.01). Regressions of BW, ADG and weight at 15, 30, 45 and 60 days age of lambs on dam weight after lambing were signi¿ cant (P 0.001). Likewise, live weight of lambs at birth, ADG until weaning and live weight at 15, 30 a 45 days of age were affected by the year of lambing (P 0.001). Results indicate that the CA and RA crossbred sheep showed better growth performance than purebred Awassi, which may presumably indicate the effect of hybrid vigour in ¿ rst generation crosses compared with pure Awassi.