DIFFERENT REARING INTENSITIES OF GILTS - I - EFFECTS ON SUBSEQUENT MILK-YIELD AND REPRODUCTION

Growth, subsequent milk yield and subsequent reproduction traits were recorded in an initial number of 72 gilts subjected to one of three di fferent rearing intensities, Semi ad lib. feeding (ad libitum for 30 m in at the two daily feedings), Control (Danish standards), and 75% Con trol. The treatments were imposed between 6 weeks of age and mating. D uring four subsequent pregnancy and lactation periods, all animals wer e fed according to Danish standards. Daily gain between 6 weeks and 18 0 days of age was 717 g for Semi ad lib., 669 g for Control, and 552 g for 75% Control gilts. Age at mating was similar (221-225 days) in th e three treatments, while weight at mating was 134 kg for Semi ad lib, , 127 kg for Control, and 110 kg for 75% Control pigs. Average daily m ilk yield over four lactation periods was similar in all treatments (6 .9-7.0 kg). Average litter size was between 9.1 and 10.1 live born pig lets, and there was a tendency(P = 0.14) towards a smaller litter size in 75% Control. For unknown reasons, animals in Control treatment had the lowest weight gain during pregnancy, while weight loss during lac tation was similar. The interval from weaning to first oestrus was not affected by treatment. Ultrasound measurements of fat and muscle dept hs showed differences during the rearing period, but these differences levelled off as the experiment progressed. (C) 1998 Elsevier Science B.V. All rights reserved.