Response of Youzhou black goats to stress from natural pastures deficient in minerals

Youzhou black goats in mineral-imbalanced pastures exhibited clinical symptoms such as widespread diarrhea and weight loss. To investigate the impact of pasture mineral imbalance on these goats, Zhangjiaping pasture (mineral-imbalanced) and Maoba pasture (in a healthy area) were selected as experimental and control sites, respectively, and the mineral elements in soil and forage were determined. Quantitative analysis revealed significantly lower selenium (Se) levels in both soil and forage at the experimental site compared to controls (P < 0.05). In contrast, sulfur (S) concentrations were elevated exclusively in forage (P < 0.05), with no significant differences observed in soil S content. Twelve healthy male Youzhou black goats (5 months old; body weight 12.61 ± 0.18 kg) were randomly allocated to experimental or control sites (n = 6 per group) and maintained in assigned pastures for a 60-day experimental grazing period.The results showed that all the goats in the experimental group showed clinical symptoms during the grazing period, including diarrhea (5/6), depression (6/6), and unsteadiness (4/6), whereas control animals exhibited no adverse signs. Experimental goats showed significantly lower blood/liver copper (Cu) and Se levels (P < 0.05) and higher S levels (P < 0.05) compared to controls. The results of blood physiological and biochemical indexes showed that the goats in the experimental group had a tendency towards anemia, and their antioxidant capacity and immune capacity were significantly reduced. The results of the liver metabolome showed that multi-element complex stress significantly affected amino acid metabolism and nucleotide metabolism pathways in black goats. After supplying copper sulpate (CuSO₄) orally and injecting sodium selenite (Na₂SeO₃) into affected black goats, the Se and Cu levels in the goats gradually increased and returned to normal levels. In summary, this study elucidates the multiple effects of pasture mineral imbalance in Youzhou black goats, indicating that the mass clinical symptoms in Youzhou black goats are closely related to mineral imbalance in the pasture.