UTILISATION DES POMMES DE TERRE DESHYDRATÉES ET FRAICHES DANS L'ALIMENTATION DU PORC EN CROISSANCE, EN COMPARAISON AVEC L'ORGE

Abstract

In one experiment (A) 3 groups of 13 Large White pigs of 30 kg initial liveweight were fed to 100 kg liveweight on the Lehmann system. They were given daily 300 g concentrate with 44% crude protein and, for the respective groups: barley to appetite (Group 1); 1200 g barley and dried potatoes to appetite (Group 2); 1200 g barley and freshly cooked potatoes to appetite (Group 3). In another experiment (B) 6 pigs were put in digestibility cages between 40 and 70 kg liveweight and were fed as the groups in the 1st experiment, in a Latin square design, in order to estimate the digestibility of energy and N of the feed by difference. From the results obtained in the interval between 30 and 100 kg live-weight average daily gain in g per day and index of consumption, intake of dry matter per kg gained, were for groups 1, 2 and 3, respectively, 672 g and 3. 35 kg, 568 g and 3. 67 kg and 592 g and 3. 35 kg. Corresponding values for criteria of carcass composition, carcass yield, percentage lean cuts (ham and loin) and fat cuts (back and belly) in the carcass and mean depth of back fat [image] in mm were, respectively: Group 1, 72. 3, 48. 6, 19. 8 and 30. 7; group 2, 70. 9, 50. 0, 19. 3 and 28. 9; group 3, 70. 3, 52. 4, 17. 1 and 26. 2. Percentage digestibility of energy and of crude protein and energy value expressed as kcal digestible energy per kg dry matter were for barley 77. 2, 65. 3 and 3531, for dried potatoes 80. 9, 35. 4 and 3352 and for cooked potatoes 85. 4, 49. 8 and 3761. Giving fresh potatoes in the diet reduced growth rate compared with barley but the intake of dry matter per kg gained was comparable, and the carcasses were leaner. With this method of feeding potatoes supplied 37% of the total intake of dry matter. In contrast, dried potatoes compared with fresh tubers reduced performance as regards growth rate, intake of dry matter per unit gained and carcass quality; between 30 and 100 kg liveweight the dried product supplied 40% of the total intake of dry matter. The replacement value of dried potatoes was 0. 8 kg barley (or feed unit) per kg against 0. 27 kg barley per kg for fresh tubers, equivalent to 0. 9 and 1. 1 feed units per kg dry matter. The reduced feeding value of the dried potatoes compared with the fresh product could be considered at least in part due to faulty preparation; the potatoes were not washed, and they were overheated during drying.