Effects of pigeon pea leaves and concentrate mixture on feed intake, milk yield, and composition of crossbred dairy cows fed native pasture hay

Abstract

Protein supplements are expensive and not easily accessible under small-scale livestock production systems in Ethiopia and other developing countries, which necessitates investigating the alternative protein sources for cost-effective livestock production. Pigeon pea (Cajanus cajan L. Millsp) leaves (PPLs) are rich in protein and are well-suited for feeding small ruminants; however, the effect of inclusion of PPL in the concentrate mixture (CM) on the performance of dairy cows was not well documented. This experiment was conducted to evaluate the effect of supplementation of PPL and CM to native pasture hay-based rations on feed intake, milk yield and composition, and blood metabolites of crossbred dairy cows (Holstein × Zebu). A 4 × 4 Latin square design with three replications, balanced for carryover effects, was used for this study. The treatments included native pasture hay provided ad libitum as a basal diet, supplemented with a CM alone (T1), the inclusion of 10% of PPL in the CM (T2), 20% PPL in the CM (T3), or 30% PPL in the CM (T4). Supplements were isocaloric and isonitrogenous. Total DM intake (hay + supplement intake) was similar (P > 0.05) among treatments. Hay intake was greater (P = 0.05) for T1 and T2 than for T4, while supplement intake was the least for T1 (P < 0.05). The treatment groups T2, T3, and T4, where PPL was included, had similar (P > 0.05) supplement intake. Feed intake, milk yield and composition, feed conversion efficiency, body condition score, serum total protein, albumin, globulin, glucose, triglyceride, urea N, creatinine, and cholesterol were similar (P > 0.05) among treatments. The inclusion of up to 30% of PPL in the CM resulted in a comparable performance of crossbred dairy cows as supplementation with CM under the conditions of the current experiment. Therefore, further study is required to evaluate the effect of the inclusion of a higher level of PPL in the concentrate mixture on the performance of lactating crossbred dairy cows.

Keywords: Body condition; Milk fat; Milk protein; Protein supplement; Serum metabolite.