Effect of index selection for reduced backfat thickness and increased growth rate on sow weight changes through two parities in swine

Abstract

Effect of index selection for reduced backfat thickness and increased growth rate on sow weight changes through two parities in swine McKay, R. M. 1992. Effect of index selection for reduced backfat thickness and increased growth rate on sow weight changes through two parities in swine. Can. J. Anim. . The impact of continued selection for reduced backfat thickness and improved growth rate on weight changes in Yorkshire and Hampshire sows, from breeding as giits to weaning their second litter, was studied.Results suggest that some sow weight changes may have been influenced by selection pressure exerted.Key words: Sows, Canadian Yorkshire, Hampshire, liveweight change McKay, R. M. 1992. Effet de la s6lection pour la r6duction de l'dpaisseur du lard dorsal et pour I'augmentation du taux de croissance sur les modifications du poids des truies jusqu'ir la deuxibme mise bas. Can. J. Anim. . L'auteur a 6tudi6 I'effet d'une s6lection pour la r6duction de l'6paisseur du lard dorsal et pour I'am6lioration du taux de gain sur les modifications du poids des truies Yorkshire et Hampshire )r partir de leur premidre mise ir la reproduction jusqu'au sevrage de leur seconde port6e. Les r6sultats obtenus indiquent que certaines modifications de poids pourraient avoir 6t6 influenc6es par la pression de sdlection exercde. In either breed, there were only two sow weight changes that exhibited conclusive differences between the select and control lines. Though the presence of these differences does not prove conclusively that there was an effect due to the selection practised they also do not prove that selection had no effect. o-E--

Interactive effects of selection for lower backfat and dietary pyridoxine levels on reproduction, and nutrient metabolism during the gestation period in Yorkshire and Hampshire sows

“…2, Hampshires tended to produce more live pigs of lighter weight, and there was a significant line-within-breed by diet interaction on live pigs born. Piglet birth weights were not significantly improved by feeding diet 2, and this was in agreement with the findings of Ritchie et al (1960). Feeding increased pyridoxine in sow gestation diets did not significantly influence the 3 wk piglet weight gains in exp.…”

“…Relatively little information is available on the effect of dietary supplemental pyridoxine on reproduction and nutrient metabolism in sows. Ritchie et al (1960) reported no improvement in litter size of sows fed corn-oat-soybean meal gestation diet supplemented with 11.0 ppm pyridoxine; however, the feeding of supplemental pyridoxine was started in this study from the second month of gestation. Easter et al (1983) reported that gilts fed supplemental pyridoxine at 1.0 ppm to corn-soybean meal diets containing 2.8 ppm available pyridoxine fed from breeding through gestation had increased number of live pigs born (9.7 vs. 8.5, P < 0.05) and weaned (8.7 vs. 7.4, P < 0.07).…”

“…Two experiments were conducted, using second-parity Yorkshire and Hampshire sows from two lines, one kept as a control and the other selected for a lower backfat thickness over six generations (McKay 1990(McKay , 1992. After weaning, all sows were housed in individual gestation stalls in a total confinement, heated building.…”

The effect of selection for residual feed intake during the grow/finish phase of production on feeding behavior traits and sow reproduction and lactation efficiency in Yorkshire pigs

“…However, like our study, sow backfat depth at farrowing was less in lines selected for components of lean growth than in control lines (Kerr and Cameron, 1996;Cameron et al, 2002). Unlike our study, weight loss and backfat loss tended to be equal between lines selected for lean growth and control lines (McKay, 1992;Kerr and Cameron, 1996;Cameron et al, 2002). Sow feed intake was less in lines selected for daily feed intake and lean food conversion but greater in lines selected for lean growth rate (Kerr and Cameron, 1996;Cameron et al, 2002).…”

Effects of selection for lower backfat, and increased dietary lysine level to digestible energy with supplemental threonine and methionine on lactation performance of Yorkshire and Hampshire sows

“…The differences in backfat between the two lines in both experiments were probably due to metabolic differences in partitioning of nutrients for lean and fat tissue deposition (Pettigrew et al 1993). McKay (1992) reported that the body weight loss during lactation was higher in Yorkshire than Hampshire, and higher in select than control line sows which was probably due to a limit-feeding of sows during lactation in that study. Although sow weight gains and backfat retention tended to be superior in Hampshire and select lines of sows fed diet 2, the interactions were not significant.…”