Addition of calcium propionate to finishing lamb diets

Abstract

Calcium (Ca) propionate can be added to ruminant diets as a glucogenic substrate. However, due to its hypophagic effect, it is necessary to establish the optimal dose that can be used to replace grains in finishing diets for lambs. Therefore, the objective of this study was to assess the effect of four concentrations of Ca propionate in lamb diets on productive performance and rumen fermentation. Thirty two Hampshire x Suffolk lambs (23.82 ± 0.40 kg initial body weight), distributed in a completely randomized design, were given a diet with four concentrations of Ca propionate (g kg−1): 0, 10, 20 or 30 g, for 42 days. The results were tested for linear or quadratic responses. The final weight, average daily gain and feed: gain ratio showed quadratic responses (P ≤ 0.01). The optimal dose was established at 13.77 g kg−1 DM. Addition of Ca propionate did not affect variables related to rumen fermentation (pH, total volatile fatty acids, acetate, butyrate or rumen ammonia-N; P ≥ 0.05) . Nonetheless, glucose and propionate concentrations showed a quadratic response (P ≤ 0.05). The highest concentrations of propionate in rumen were observed with 15.14 g kg−1 DM. Results indicate that Ca propionate can be included in a dose of up to 13.77 g kg−1 DM in feedlot rations, to attain best lamb performance.