Effects of different quality diets consumed continuously or after a lower quality diet on characteristics of growth of young Spanish goats

There are several feeding options available to goat producers with fall-born kids. One for kids weaned in the winter is to graze or be fed harvested low-quality forage, such as prairie grass or prairie hay, which is usually abundant in winters. For many producers, this might be followed by consumption of relatively high quality forage or browse in the spring or, for others, there could be immediate or delayed placement on high grain diets. Therefore, the objective of this study was to elucidate effects of consuming different quality diets continuously or with an increase in diet quality during the latter part of the growing period on characteristics of growth by fall-born Spanish kids.The experiment consisted of two 9-wk periods. Diets were low quality forage (L; prairie hay supplemented with soybean meal), high quality forage (H; dehydrated alfalfa pellets), and 70% concentrate (C). Kids on two treatments consumed L in Period 1, with half switched to C and half to H in Period 2 (LC and LH, respectively). The CC treatment entailed C consumption in both periods, and HH kids were fed H in both periods. For HC, H was fed in Period 1 followed by C in Period 2. Results indicated that diets high in concentrate may yield ADG similar to that for high quality forage but with greater fat deposition in both carcass and noncarcass components. Switching from a high quality forage to a concentrate-based diet resulted in ADG similar to that with continuous intake of both diets, but with increased fat and decreased protein deposition compared with continuous intake of high quality forage. Little or no BW change for kids consuming low quality forage, with fat mobilization to accrete a small amount of protein, resulted in smaller differences in subsequent fat and protein accretion when changed to high quality forage or a concentrate-based diet compared with continuous intake of high quality forage or a concentrate-based diet. In conclusion, the nature of the diet consumed by young Spanish goats can impact rate and characteristics of tissue accretion.