Energy-protein supplementation enhances milk production and nutritional status of lactating goats under sorghum stubble

Abstract

The general objective of this study was to evaluate the effects of four energy-protein supplements on the nutritional status, blood metabolites, milk yield, and milk quality of lactating goats adapted to the Comarca Lagunera region and fed a basal diet of sorghum stover. Sixteen goats with similar initial live weight (41.52±1.8 kg) and body condition (2.1±0.2) were randomly assigned to one of four dietary treatments: alfalfa hay (GA), dried distillers' grains (DDG), corn gluten meal (CG), and wheat milling by-products (WM) (n=4 per treatment). The animals were managed individually and underwent an 8-day supplement adaptation period, followed by a 30-day experimental phase. Dry matter intake was significantly higher (p<0.05) in goats supplemented with alfalfa hay compared to the other treatments. Daily weight gain was higher (p<0.05) in the GA and WM groups, indicating better energy utilization with these supplementation strategies. No significant differences in blood metabolites were found among treatments (p>0.05), although numerically higher values were observed in the DDG group. Milk yield was significantly affected by supplementation (p<0.05); goats receiving corn gluten meal showed the highest production, differing from the GA group. Conversely, milk composition parameters were not affected by dietary treatment (p>0.05), suggesting that the type of supplement influenced production volume more than milk quality attributes. Overall, energy-protein supplementation improved nutrient intake and enhanced the productive performance of goats consuming low-quality sorghum stover. While all supplements maintained acceptable body condition and metabolic stability, corn gluten meal demonstrated a superior effect on milk production.