| Popis: |
Betaine improves growth performance and health in monogastric animals under both thermoneutral and heat stress conditions, but results in ruminants have been more equivocal. This meta-analysis investigated the effects of betaine supplementation on productive performance, milk production and composition, and carcass traits of ruminants due to betaine supplementation. A comprehensive search for published studies investigating the effect of betaine was performed using Google Scholar, ScienceDirect, PubMed, and Scopus databases. Effect size analysis, random effects models, I2 statistics, and meta-regression analysis were utilized to assess differences in production parameters. Dietary betaine supplementation increased milk yield (+1.0 kg/d (weighted mean differences presented in this abstract), p < 0.001), dry matter intake (+0.15 kg/d, p < 0.001), and milk lactose (+0.05%, p = 0.010) in dairy cows housed under thermoneutral conditions. In the few studies conducted on small ruminants, there was an increase in milk yield in response to dietary betaine (0.45 kg/d, p = 0.040). Under heat stress conditions or grazing pasture during summer, dietary betaine increased milk yield (+1.0 kg/d, p < 0.001) and dry matter intake (+0.21 kg/d, p = 0.020). Dietary betaine increased final liveweight (+2.33 kg, p = 0.050) and back fat thickness (+0.74 cm, p < 0.001) in beef cattle. Dietary betaine increased final liveweight (0.14 kg, p = 0.010), daily gain (+0.019 kg/d, p < 0.001), and carcass weight (+0.80 kg, p < 0.001) but not backfat in small ruminants. These meta-analyses showed that dietary betaine increases liveweight in small ruminants and beef cattle and increases feed intake and milk yield in dairy cattle. |
