The feeding value of whey mother liquor in comparison with whey and with meal for growing-finishing pigs

Abstract

In two group-feeding trials the optimal degree of dilution of whey mother liquor and its comparative feeding .value when forming the major ingredient in rations for growing-finishing pigs were assessed. Each trial involved 32 pigs and consisted of four treatments with two pen groups of four pigs per treatment. In the first trial, in addition to a constant daily meal allowance (2 lb, reducing to 1 3/4 lb per pig from 95 lb live weight), mother liquor (48% d.m.) was fed diluted 1:1, 1:3, 1:5, or 1:9 with water. All groups were also provided with unrestricted but measured quantities of drinking water. From 50 to 150 lb live weight, mean growth rates for the treatment groups fed mother liquor diluted 1: 1, 1: 5, and 1: 9 were respectively 6, 8, and 11 % less (P < .05) than for those fed mother liquor diluted 1 :3. Those groups fed the 1:5 and 1:9 dilutions consumed, respectively, 12 and 15% more total d.m. than those fed the 1:3 dilution (P < .05). Consumption of drinking water varied inversely, and total water intake varied directly, with the degree of dilution of mother liquor, the ratios of mother liquor:total water intake varying from 1:6.5 for the 1:1 and 1:3 treatments to 1:9.8 for the 1:9 treatment. It was concluded that where pigs were allowed to determine the ratio of mother liquor:water intake for themselves, the best results, in terms of rate and economy of weight gains, were obtained when this ratio was approximately 1 :6. In the second trial mother liquor, supplemented with either 1 t lb decreasing to 1 lb meal per pig daily or 2t lb decreasing to 2 lb meal per pig daily, was compared with casein whey fed in conjunction with the lower supplemental meal allowance and also with an all-meal diet fed to scale. Appropriate allowances of mother liquor and whey were derived from this scale by substituting 2.1 lb mother liquor or 17.5 lb whey per 1 lb meal. On this basis, from 50 to 150 lb live weight, the growth rates and food economies of the whey and mother liquor groups fed the smaller daily meal allowance were almost identical. The two remaining groups grew slightly (but not significantly) faster and consumed significantly (P < .05) less total d.m. There were no treatment differences in the mid-line backfat measurements of the carcasses, but those of pigs fed 1-11/2 lb meal plus whey or mother liquor were of higher specific gravity (P < .05). It was concluded that for the level of feeding used, mother liquor was equivalent in energy value to whey on a d.m. basis. By comparison varied from 1.5 lb to 2.5 lb per lb meal, depending on the proportion of meal in the diet (and, possibly, the stage of growth). For the overall period mother liquor comprised approximately 44% and 71 % of total d.m. consumption for the treatments involving the larger and smaller daily meal allowances respectively.