Effects of BCAA Supplementation on Plasma and Mare's Milk Amino Acid Contents in Yili Mares and Growth Performance of Suckling Foals

Xiang Ren^1*Yuheng Xue^2*Zhehong Shen²Xiaokang Chang²Jun Meng²Wanlu Ren²Jianwen Wang²Xinkui Yao²Xiaotian Liu²Yaqi Zeng²

• ¹Xinjiang Horse Industry Association, Urumqi, China
• ²School of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang Uyghur Region, China

This study investigated the effects of branched-chain amino acid (BCAA) supplementation on plasma and mare's milk amino acid content in lactating Yili mares and the growth performance of suckling foals(Figure 1). Eighteen mares and their foals were divided into four groups: a control group (D) and three experimental groups (S1, S2.S3) receiving 38, 76, and 114 g/d of BCAA, respectively. The trial included a 7-day adaptation period and a 60-day experimental phase. Results showed significant increases in plasma Ser (S1), Trp, His, and Asp (S3) compared to the control group. In mare's milk, Ser (in S1) and Ala (in S3) contents were significantly higher than in the control group. Foals in the S3 group had greater body weight than those in the control group. Correlation analysis revealed positive correlations between plasma and milk amino acids (Trp, Val and Thr in S1; Orn in S3). Milk Thr content changes were correlated with foal body height and length growth. BCAA supplementation at 38 g/d increased plasma and milk Ser. At 76 g/d, plasma His levels rose, positively affecting foal body height and length. The 114 g/d dose enhanced plasma Asp and Trp, milk Asp and Ala, and improved foal body weight and chest circumference.