The evaluation and standardisation of pig rations under South African conditions: 2.The influence of feeding protein and energy

Author: E.H. Kemm and M.N. Ras
Year: 1972
Issue: 2
Volume: 2
Page: 59 - 64

A total of 224 pigs were used in two experiments to study the effect of two isocaloric diets containing 16,4 or 11,7% crude-protein on rate of gain, feed conversion efficiency, carcass characteristics and carcass composition of baconers, fed ad libitum throughout the experimental period or restricted during the final period of growth. High protein (HP) pigs had free access to a 16,4% protein diet throughout the experiment, while Low protein (LP) pigs were ad lib. fed on the 11,7% diet. HP-HP and HP-LP pigs were full-fed on the 16,4% diet to 45 kg live mass. Where after a daily maximum of 2,27 kg of the 16,4% diet was fed to HP-HP pigs and a like amount of the 11, 7% diet fed to HP-LP pigs. HP pigs gained significantly faster than HP·LP pigs, while the difference between HP and HP-HP approached significance. Barrows gained significantly faster than gilts. LP pigs had significantly more back fat than HP pigs and highly significantly more back fat than HP-HP and HP-LP pigs while HP-HP resulted in a significant reduction in back fat when compared with HP. Statistically, treatment effects on C + K measurements were identical to the back fat measures except that the difference between the HP and HP-HP groups was non-significant. Gilt carcasses had highly significantly less back and C+ K fat than barrow carcasses. The eye-muscle areas of HP pigs were highly significantly larger than those of HP-LP pigs and significantly bigger than the muscle areas of LP pigs. Gilts had highly significantly larger muscle areas than barrows. LP pigs had highly significantly more carcass fat (chemically determined) than pigs in the other three treatments, while gilts had highly significantly less fat than barrows. LP pigs had highly significantly less carcass protein than pigs in the other three treatments, while gilts had highly significantly more carcass protein than barrows. Pigs used in the first trial had on average 25,5% more back fat and 27,6% more C + K fat than pigs used in the second experiment, thus emphasizing the genetic variation in ability to lay down fat existing between pigs of the same breed

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