Effects of protein and energy supplementation on growth, forage intake, forage digestion and nitrogen balance in meat goat kids

Abstract

The objective of this study was to further the understanding of the effects of dietary protein and energy supplements on growth, performance, feed intake and grass forage digestibility in growing meat goat wethers. In Experiment 1, an 18% CP complete goat pellet was offered alone (control diet, C) or added (1), or not, as supplement to three grass hays (coastal bermudagrass, CB; Tifton 85 bermudagrass, T; and sorghum-Sudan grass hay, SS), to Boer-cross wethers (n 5 72). The resulting seven diets were offered ad libitum. In Experiment 2, four wether goats in metabolism crates were used in a 4 3 4 Latin square design and fed a SS basal diet ad libitum with treatments consisting of no supplement, supplemental urea (200 mg/kg BW daily), supplemental dextrose (0.2% BW daily), or urea 1 dextrose (200 mg/kg BW daily and 0.2% BW daily, respectively). In Experiment 1, average daily gain (ADG) were 23.8, 25.0 and 26.6 g/day for goats consuming CB, T and SS, respectively, and 69.2, 61.6 and 58.1 g/day for supplemented CB (CB1), T (T1) and SS (SS1), respectively, as compared to 245.8 g/day for ad libitum access to C. Supplementation in Experiment 1 increased (P , 0.01) ADG for all hays when compared to hay-only diets. In Experiment 2, protein and energy supplementation increased (P , 0.01) nitrogen retention but did not impact diet digestibility. The beneficial effects of supplements in Experiment 1 and the increase in nitrogen retention in Experiment 2 cannot be explained by improvements in ruminal fiber utilization, but could be due to post-ruminal nutrient supply and/or increased ruminal microbial protein synthesis.Keywords: digestion, energy, goats, protein, supplementation Implications This paper indicates that growing goats, consuming one of three species of grass hay, required supplementation in order to achieve positive BW gains. In a second experiment, supplementation of protein or energy alone did not result in increased nitrogen retention or fiber digestibility. When feeding low and medium quality grass hays to growing meat goat kids, producers should consider supplementation of both protein and energy simultaneously to achieve increases in protein accretion via nitrogen retention.

Effects of nutritional level of concentrate‐based diets on meat quality and expression levels of genes related to meat quality in Hainan black goats

“…Several studies have shown that the nutritional level of diets can affect meat quality and the expression levels of genes associated with meat quality (Patterson et al . ; Hocquette et al . ; Guo et al .…”