| Abstrakt: |
Background and objectives: Considering the costs of providing feed for feeding ruminants, agricultural by-products, which are generally cheaper than conventional feeds, can be included in the diet of fattening animals, which will reduce production costs. One of these agricultural by-products is cotton waste from cotton ginning factories, which due to its plant origin and as a source of protein, fat and raw fibers, this product has the ability to be used as an alternative feed in the diet of fattening animals. This edible material is a mixture of woody parts of cotton bolls, stems, remnants of cotton fibers and leaves. This study was conducted to investigate the effects of substituting different levels of cotton waste for dried alfalfa on growth performance, quantitative and qualitative carcass traits, apparent digestibility, blood parameters, and liver enzymes Afshari lambs. Materials and methods: In this study, 24 male Afshari lambs with a mean weight of 30±1.9 kg and a mean age of 4 months were used in 4 treatments and 6 repetitions for 90 days. The experimental treatments included: 1) control group, 2) diet containing 33.33% cotton waste, 3) diet containing 66.66% cotton waste, 4) diet containing 100% cotton waste instead of dry alfalfa. Growth performance traits including daily feed intake, daily weight gain and feed conversion ratio were measured during the experiment period. Also, at the end of the experiment, three lambs from each treatment were slaughtered to measure the quantitative and qualitative traits of the carcass. On the 90th day of the experiment, blood samples were taken from five lambs from each treatment to measure blood parameters and liver enzymes. Results: The growth performance results showed that replacing 100% of cotton waste instead of dried alfalfa (1890 gr) in the diet of fattening lambs significantly increased the daily feed intake compared to the control group (P<0.05). The feed conversion ratio in the treatment containing 100% replacement of cotton waste instead of dried alfalfa (6.70) was significantly reduced compared to the control group (P<0.05). The final live weight in treatments where cotton waste was replaced by dried alfalfa was higher than the control group (P<0.05). Also, the treatment containing 100% replacement of cotton waste instead of dried alfalfa had a higher final weight (56.22 kg) than the control group and other groups. Apparent digestibility of crude fat (75.11%), NDF (69.31%) and ADF (30.32%) in the treatment containing 100% replacement of cotton waste instead of dried alfalfa compared to the control group It increased significantly (P<0.05). The concentration of blood urea nitrogen, cholesterol, triglyceride, LDL and VLDL in blood serum increased with consumption of cotton waste (P<0.05); But the concentration of HDL decreased (P<0.05). A decrease in cholesterol and blood urea nitrogen was observed by replacing 33.33% of cotton waste (P<0.05). The live weight before slaughter, hot carcass weight, hot carcass percentage, cold carcass weight, cold carcass percentage, cold half carcass weight, thigh percentage and head percentage in the treatment containing 100% replacement of cotton waste instead of dried alfalfa increased significantly compared to the control group (P<0.05). Conclusion: The general result of the present study showed that replacing 100% of cotton waste instead of alfalfa improved the growth performance, quantitative traits of the carcass and the apparent digestibility of nutrients. [ABSTRACT FROM AUTHOR] |
