Effect of sole maize and maize –lablab silage on the ruminal volatile fatty acids (VFAS) of grazing calves in the dry season

Abstract

Silages of sole maize and mixtures of maize-lablab were made at harvest in plastic bags. The experimental Unit consists of twelve cross-bred yearling bulls (White Fulani x N’dama) calves weighing 71-72kg and were randomly allotted to three dietary treatments: Grazing + sole maize silage, Grazing + mixtures of maize-lablab silage and Unsupplemented grazing as control. The experimental design was a completely randomized design and lasted 84days. Silage diets were given between 07:30 and 11:00 hours daily before grazing. Rumen fluid was collected at the end of the study to evaluate the co-efficient of ruminal fluid. The crude protein content in sole maize silage was half of that in mixture of maize-lablab silage. Inclusion of lablab in maize stover silage increased the mineral content as well as the lignin fraction. The mean pH value of sole maize silage (3.80) was less (P < 0.05) than 4.25 obtained with addition of lablab. The buffering capacity (5.37%) of sole maize silage significantly (P < 0.05) increased to 5.71% in mixture of maize-lablab silage. Lactic acid contents differed was influenced significantly (P < 0.05) with a mean value of 8.4% and 8.5% respectively in the sole maize silage and with lablab inclusion. Total volatile fatty acid (VFA) ranged from 56.7 μmoles/ml in calves without supplementation to 95.2 μmoles/ml in the calves fed mixture of maize-lablab silage. Mixture of Maize-lablab silage had the highest values for all the minerals determined in the feed materials while sole maize had the least. It was concluded from this trial, that forage legumes are relatively good sources of degradable nitrogen and fermentable energy, so their inclusion in the diet is likely to increase the rumen population of cellulolytic microbes and also proves that, mixture of maize-lablab silage could be used as supplement to enhance the growth and survival of calves during the dry season, when animal feeds are relatively scarce.

Keywords: Grazing calves; maize stover; natural pasture; volatile fatty acids