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

Protein supplements are expensive and not easily accessible under small-scale livestock production sys-tems 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 x Zebu). A 4 x 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 + supple-ment 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 com-position, 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 supplemen-tation 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.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Protein supplements are expensive and not easily accessible in small-scale livestock production systems. This study investigated the inclusion of pigeon pea leaves in the concentrate mixture for dairy cows. The results showed that including up to 30% of pigeon pea leaves in the concentrate mixture had no significant effect on feed intake, milk yield and composition, and blood metabolites of crossbred dairy cows. Further research is needed to evaluate the effect of higher levels of pigeon pea leaves in the concentrate mixture on lactating dairy cows.