Meta-analysis of effects of supplemental feeding on the growth and slaughter performance of Tibetan sheep

To evaluate the effects of supplemental feeding on the growth and slaughter performance of Tibetan sheep (Ovis aries), literature was searched on randomized controlled trials of supplementary feeding in Tibetan sheep published in Chinese and English databases, including PubMed, Web of Science, ScienceDirect, China National Knowledge Infrastructure (CNKI), Wanfang Data, and China Science and Technology Journal Database, from the time the database was created until April 2023. Following that, a Meta-analysis was conducted to merge and analyze relevant research literature. Finally, 28 articles were screened for Meta-analysis out of the 1689 articles. The results showed that the average daily gain (ADG), net weight gain, dressing percentage, carcass weight, weight- adjusted fatness value (GR ) (P < 0.001), and eye muscle area (P < 0.05) of the Tibetan sheep in the supplemental feeding group were significantly higher than those in the no supplemental feeding group. Subgroup analysis showed the best effect of concentrate supplementation on ADG of the sheep, which increased with increasing concentrate supplementation level and supplemental feeding days. In contrast, the ADG decreased with increasing age of the sheep, with the most prominent effect observed for sheep under 6 months. Sensitivity analysis using a one-by-one elimination method showed that the results of improved growth and slaughter performance of Tibetan sheep with supplementary feeding were stable. Publication bias analysis showed no publication bias (P < 0.05) for most of the indicators, except ADG, net gain, and carcass weight. In the present study, using Meta-analysis, it was confirmed that supplemental feeding can improve the growth and slaughter performance of Tibetan sheep, which can provide a theoretical basis and data support for the accurate nutrition management of Tibetan sheep.