Effect of chopping and level of inclusion of whole sugar cane in the diet on intake and growth of goats

Abstract

A total of 156 crossbred goats (F1 of India×Bachthao) with an initial weight of 10.2–11.9 kg and ages ranging between 3.5 and 4 months were used in studies to examine how physical form and inclusion level of sugar cane influenced intake. In the intake study whole sugar cane was divided into leaves, tops and stalks. The leaves were offered chopped into five different lengths (5, 10, 15, 20 and 25 cm) and a control group was given whole leaves. The sugar cane tops were chopped into: (i) slices (1–3 cm), (ii) 15-cm lengths and split into two parts, (iii) 20-cm lengths and split into four parts. The sugar cane stalks were chopped in three different ways: (i) slices (1–3 cm), (ii), 20-cm lengths and rind removed, and (iii) 15-cm lengths and split into four parts but with the rind remaining. The goats were given a basal diet of concentrate and molasses–urea blocks. The results of the intake study showed that slicing the sugar cane stalks into small pieces (1–3 cm) resulted in a significant increase in feed intake, while there were no important differences between the different methods used for processing sugar cane leaves or tops in terms of voluntary dry matter (DM) intake. In the rate of inclusion study the goats were fed a basal diet of concentrate, a molasses–urea block and jack fruit leaves. Chopped whole sugar cane (CWSC) was combined with guinea grass at different ratios to provide 0, 15, 30, 45, 60 and 75% sugar cane on a DM basis. The actual intakes achieved were 0, 13, 23, 26, 37 and 51% CWSC, respectively, of DM. The results showed that when using CWSC in the diet for growing goats, an inclusion of 30% total DM resulting in a consumption of 23% of DM was optimal in terms of liveweight gain, feed conversion ratio and feed costs. DM digestibility was not significantly different for the treatments in the latter study (62.2–66.7%), but crude fibre digestibility was highest for the treatment without sugar cane and lowest for the treatment with the highest consumption of CWSC. A weak negative relationship was identified between the digestibility of crude fibre ( Y) and the proportion of CWSC ( X) in the diets represented by equation: Y=0.597–0.0017 X, r 2=0.016