Evaluation of animal feed blocks made from whey and whey ultrafiltrate.

Abstract

Proc. Aust. Soc. Anim. Prod. (1978) 12: 181 EVALUATION OF ANIMAL FEED BLOCKS MADE FROM WHEY AND WHEY ULTRAFILTRATE J.A. STEWART*, J.W. TAYLOR* and R.D. MacBEAN** Acceptable outlets for whey are needed to comply with environment protection laws. With animals at pasture there may occasionally be a need for supplementary energy kOS prophylactics. Molasses based blocks are available for these purposes and this report is concerned with the evaluation of whey (W) or whey ultrafiltrate (WUF) as a substitute for molasses (M) with or without the incorporation of 35 % magnesium oxide &Jo) I a supplement used to control grass tetany (hypomagnesaemia). Feed blocks with W or WUF, + MgO, were made as described by Hargrove, McDonough and Alford (1974) whilst M and M+MgO blocks were obtained from commercial sources. Three blocks of each of the six types were offered separately to one of six herds of 16 fifteen month old dairy heifers (mean live weight 248 kg) grazing ad lib. perennial pasture in 2 ha paddocks in spring. The relative hardnzs of each block was measured as the penetration of a 20 mm2 probe, weighted to 615 g, dropped down a tube from a height of 280 mm. Blocks were weighed at the start and end of a three week feeding period and changes corrected for weathering effects on control blocks placed in animal exclosures. TABLE 1: Probe penetration, block weight and disappearance and animal intake. Proportionate animal intake of the relatively soft W and WUF blocks was estimated to be similar to the 25 % of total intake reported by Hargrove, McDonough and Alford (1974) for younger animals in a feedlot. These blocks could serve as an energy supplement provided their use could be economically justified. Addition of 35 % Mg0 to W or WUF produced hard blocks which, unlike M or M+MgO, did'not exhibit surface deliquescence. Negligible consumption indicates that these combinations are unsuitable for Mg supplementation although lower levels of Mg0 might be suitable for supplementation or for controlling intake. Incorporation1 of other prophylactics also needs investigation. HARGROVE, R.E., McDONOUGH, F.E. and ALFORD, J.A. (1974). Food Engineering - : 77. 46 * ** Ellinbank Dairy Research Station, Department of Agriculture, Warragul Victoria 3820 Gilbert Chandler Institute of Dairy Technology, Department of Agriculture, Werribee, Victoria 3030. 181.