Reproductive performance of pigs selected for components of efficient lean growth

Abstract

Correlated responses in reproductive performance to five generations of divergent selection for daily food intake (DFI), lean food conversion (LFC), lean growth rate on ad-libitum feeding (LGA), and lean growth rate on scale feeding (LGS) were studied. Litter traits were measured on 1220 Large White gilts. Mean litter weights at birth and weaning were 12-9 kg and 63-5 kg, with average litter sizes of 10-3 and 7-9. Responses to selection in the high and low lines for litter size in the DFI and LFC selection groups were 1-9 and -1-5 (s.e.d. VI) at birth and 0-9 and -1-8 (s.e.d. 1-2) at weaning. Responses in litter birth weights were respectively positive and negative for kg) and the response in LGS (3 kg) was greater than in LGA (-0-1 kg). Selection line differences in litter weaning weight followed a similar pattern to birth weight for kg). Responses in litter weights were a result of selection line differences in both litter sizes and piglet weights. The relationships between litter size, litter weights and piglet weights at birth and weaning were essentially linear.An extra piglet at birth and weaning corresponded to an increase of 1-0 (s.e. 0-02) kg and 6-9 (s.e. 0-1) kg in litter weights. Piglet birth and weaning weights were decreased by 0-03 (s.e. 0-003) kg and 0-19 (s.e. 0-02) kg. A uterine constraint on piglet growth was implied, but there was no evidence for a limit to uterine capacity. Heritabilities for litter size, weight and piglet weight at birth of 0-06, 0-11 (s.e. 0-04) and 0-16 (s.e. 0-02) respectively were similar to those at weaning. Common environmental effects on piglet weights at birth and weaning were substantially higher than the heritabilities (0-38 and 0-45, s.e. 0-01). The study indicated that selection for lean growth on either an ad-libitum or restricted feeding regime did not significantly affect reproductive performance, but the high lean food conversion ratio and low daily food intake selection lines had impaired reproductive performance.

Estimation of genetic parameters for farrowing traits in purebred Landrace and Large White pigs

“…The genetic improvement of NBA is important to increase the number of piglets weaned, but the heritability of NBA is low, as also shown in this study ( (Kerr & Cameron, 1995;Roehe, 1999;Sorensen et al, 2000). The traits studied can all be measured at the same time and there is a complex relationship between them.…”

“…The traits studied can all be measured at the same time and there is a complex relationship between them. The genetic improvement of NBA is important to increase the number of piglets weaned, but the heritability of NBA is low, as also shown in this study ( (Kerr & Cameron, 1995;Roehe, 1999;Sorensen et al, 2000). Therefore, to simultaneously improve the number and weight of piglets, it is crucial to understand the genetic correlation between them.…”

“…Negative associations have been reported between litter size and individual birth weight in some studies (Kerr & Cameron, 1995;Roehe, 1999;Sorensen, Vernersen, & Andersen, 2000). The heritability of NBA has been estimated to be low in the previous studies (e.g., Damgaard, Rydhmer, Løvendahl, & Grandinson, 2003;Farkas et al, 2007;Lopez, Kim, Makumbe, Song, & Seo, 2017).…”

Effect of a GnRH analogue (peforelin) on the litter performance of gilts and sows

“…This was the case for the eCG treated group in gilts in this study. Hence, the lower birth weights in this treatment group over all parity groups was possibly caused by the differences in total and live born piglets, as piglets born in a large litter mostly have lower birth weights, compared to piglets in small litters [25–28]. …”

Abstracts from the 15th Biennial Conference of APSA

“…A supplemental multi-enzyme blend caused similar performance and CTTAD of GE and CP to pigs fed an antibiotic in the early phase of weaning, suggesting that a feed enzyme mix such as that used in the present study could be a tool for managing the growth performance challenges immediately after weaning. The incidences of piglets born dead or with low viability remains unacceptably high in the pig industry, and is likely to increase with continuing selection for high total litter size (Kerr and Cameron 1995;Rootwelt et al 2012). Caffeine promoted breathing respiration in premature human babies (Benowitz 1990) and administration of caffeine to sows 24 h prior to an induced parturition improved aspects of neonatal piglet performance (Superchi et al 2013).…”