A nutritional evaluation of diets containing meat meal for growing pigs. 4. Differences in growth of pigs on different meals and in chemical and chick tests of these meals

Abstract

Experiments were conducted to estimate the variability in growth promoting ability of seven meat meals (MM) or meat and bone meals (MBM) for pigs and the relationship between pig growth and chemical or chick tests. The meals were fed as the sole protein supplement in wheat-based diets to Large White pigs over the 18-73 kg growth phase. The diets were fed at the restricted rate of 7.2 g crude protein and approximately 114 kcal digestible energy per kg liveweight per day. The nitrogen retention of pigs and dry and organic matter digestibilities of the diets were determined. With the nutritional regime adopted, there was little difference (12 per cent) in the growth promoting ability of the seven diets for pigs, with one brand inferior to the other six. This difference appeared to be due to lower protein quality. The seven meals varied considerably in chemical composition (bone content 22-55 per cent, crude protein 45-59 per cent). There appeared little relationship between chemical composition of the diets and their growth promoting ability. Dietary calcium levels varied from 1.6-3.0 per cent but there was no apparent effect of calcium level on pig growth. 'Available' lysine levels in the meal varied from 3.1-3.7 per cent with the inferior meal having the lowest available lysine content. All diets contained considerable quantities of minerals as a result of the inclusion of MM or MBM and the diets contained the estimated requirements of pigs for major minerals. There was little relationship between chick growth on the seven diets and pig growth (r = 0.11). Chick growth was correlated with dietary calcium (r = -0.72) and feed intake (r = 0.64). When the diets were equalized for calcium, the relationship between chick growth and pig growth increased (r = 0.62). The results indicated that the calcium content of a meal was a major factor affecting its growth promoting ability for chicks but not for pigs. As the depressed chick growth was associated with lowered feed intake under ad lib. feeding, it was possible that the restricted feeding of the diets to the pigs minimized the development of depressing effects of calcium.