Effect of select dietary trace minerals levels on nutrient utilization, minerals balance and growth performance in male goats under thermoneutral and heat stress conditions.

An experiment was carried out to assess the effect of select dietary trace mineral levels under two different climatic conditions on the performance of goats. For this, 22 male goats with 21.35 ± 0.57 kg mean body weight were distributed randomly into four groups. Goats were fed three incremental levels of trace minerals (TM) selenium (Se), zinc (Zn), copper (Cu) and manganese (Mn) and designated as TM1 (0.211 ppm Se, 41.33 ppm Zn, 8.82 ppm Cu and 36.13 ppm Mn), TM2 (0.511 ppm Se, 61.33 ppm Zn, 18.82 ppm Cu and 56.13 ppm Mn), and TM3 (0.811 ppm Se, 81.33 ppm Zn, 28.82 ppm Cu and 76.13 ppm Mn). Two environmental conditions were thermoneutral [TN; 67.75 Temperature Humidity Index (THI)] and heat stress (HS; 85.47 THI), and the exposure period was 40 days. Four experimental groups were TN-TM1, HS-TM1, HS-TM2, and HS-TM3. The TN-TM1 group showed a higher intake of all nutrients (P < 0.05), and HS-TM3 group had comparable crude protein and concentrate mixture intake to the TN-TM1 group. Digestibility of dry matter and organic matter was lower (P < 0.05) in HS-TM1 group, while ether extract digestibility was higher in HS-TM3 group compared with other groups. Total digestible nutrients content of the diet improved (P < 0.05) in HS-TM3 group and digestible organic matter and nitrogen and phosphorus absorption were greater (P < 0.05) in HS-TM3 and TN-TM1 groups, compared to other groups. The Cu balance was lesser (P ≤ 0.001) in HS-TM1 group and Mn balance showed improvement (P < 0.01) in HS-TM3 group compared to other groups. The Se balance was higher (P < 0.05) in HS-TM2 and HS-TM3 groups. The weekly body weight was similar, while weekly dry matter intake and average daily gain were higher (P ≤ 0.001) in TN-TM1 compared to HS groups. Thus, feeding higher levels of 0.811 ppm Se, 81.33 ppm Zn, 28.82 ppm Cu, and 76.13 ppm Mn under HS conditions resulted in increased nutrient digestibility, N absorption, and balance of trace minerals and had a subtle favorable impact on the growth performance of goats.