Effect of Whey Protein-Enriched Water on Performance and in Vivo Carcass Measurements in Fattening Merino Lambs

Whey, a by-product of the dairy industry, is primarily used for protein and energy sources in livestock diets due to its high nutritional value, which equivalent to grain corn and barley. In the current study, whey powder was added to lamb drink water to evaluate its effects on performance and in vivo carcass measurements. Twenty-four non-castrated healthy male Merino lambs with an average of 3 months weaning age and 23.44 +/- 0.62 kg (mean +/- SE) initial live weight (LW) used in this study. Lambs were randomly allocated into two trial groups according to their LW and adapted to concentrate and whey protein-enriched water. The total period of trial was 45 days, with 15 days adaptation and 30 days for data collection. Lambs were housed in a group and received ad libitum wheat straw, lamb-grower feed, and water (enriched with whey protein or not). There were no significant differences observed in treatment groups for total weight gain (TWG, P > 0.05). On the other hand, the whey-treated group's average TWG value is 8.60% higher than the control group. Besides, the differences between initial and final loin eye depth (LED) was 4.7 times higher in the whey group than the control group (0.28 cm vs. 0.06 cm). Also, no significant differences were observed between the trial group for fat thickness (P > 0.05). Obtained results from the present study indicated that using whey powder even in animal drinks improved TWG and LED in the fattening period.