South African Journal of Animal Science
On-line version ISSN 2221-4062
ABSALAN, M. et al. Feeding of whole cottonseed on performance, carcass characteristics and intestinal morphology of Zandi lambs. S. Afr. j. anim. sci. [online]. 2011, vol.41, n.3, pp. 309-317. ISSN 2221-4062.
The present study was conducted to determine the effect of including different levels of whole cottonseed (WCS) in the finishing diet of lambs on their dry matter intake (DMI), live weight gain, feed conversion ratio (FCR, kg feed/kg gain), carcass characteristics and small intestinal morphology. Twenty Zandi male lambs (29.8 ± 1.6 kg body weight) were assigned to one of four diets in a completely randomized experimental design. The experimental diets contained 0%, 4%, 8% and 16% WCS on a dry matter (DM) basis. The diets were prepared as total mixed rations and fed to the lambs ad libitum. The lambs were slaughtered on day 90 and carcass data was collected. The DMI and average daily gain (ADG) were significantly greater for lambs fed the 8% WCS diet compared with the other treatments. The FCR was significantly lower in the diets containing WCS compared to the control, viz. 6.11, 5.6, 5.46 and 5.68, for treatments 0, 4, 8 and 16% of WCS, respectively. However, the positive effects of including 8% cottonseed in the diet were significant in hot carcass weight, dressing percentage, liver, fat tail, intestinal fat and spleen compared with the control group. Furthermore, villous morphology and depth of crypt gland were affected by both diet and sampling site. No negative effects were observed in the organs and carcasses of the lambs that received different diets. The results indicate that the inclusion of 8% WCS in lamb diets could have a positive effect on most of the traits, but increasing the WCS inclusion up to 16% in the diet may have negative effects on lamb performance.
Keywords : Growth; finishing diet; carcass; sheep; gossypol.