Interrelationships Between Sex and Exogenous Growth Hormone Administration on Performance, Body Composition and Protein and Fat Accretion of Growing Pigs

Abstract

Forty-five pigs with an average initial live weight of 60 kg were used to investigate the effects of daily exogenous porcine pituitary growth hormone administration at two dose levels (pGH; 0, excipient buffer injected, and 100 micrograms.kg-1.d-1) for a 31-d period on the performance and body composition of boars, gilts and barrows allowed to consume feed ad libitum. Excipient boars consumed less feed, exhibited faster and more efficient growth (P less than .01) and produced less fat and more protein and water (P less than .01) in the empty body compared with excipient barrows, which in turn contained more fat and less water (P less than .05) in the empty body than did excipient gilts. These differences were largely eliminated by pGH administration, which induced differential effects in growth performance and body composition in boars, gilts and barrows. Growth hormone administration improved growth rate by 13, 22 and 16% and feed conversion efficiency by 19, 34 and 32% in boars, gilts and barrows, respectively. The reduction of body fat content (g/kg) elicited by pGH was 22, 36 and 33% for boars, gilts and barrows, respectively, with a corresponding increase (P less than .01) of body protein and water content. The magnitude of the pGH responses was greatest for gilts and barrows compared with boars, negating intrinsic sex-effect differences in growth performance and body composition of pigs. Pigs used in this study and treated with pGH exhibited a rate of protein deposition (approximately 225 g/d) far greater than previously reported, and as such redefine the genetic capacity for lean tissue growth by the pig.

Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet

“…These findings are in line with recent studies reporting a tendency towards lower ADG for entire males reared in group compared to castrates (Dunshea et al, 2001;D'Souza and Mullan, 2002;Suster et al, 2006). Contrarily, some previous studies reported that entire male pigs had higher ADG and better FCR than castrates (Whittemore et al, 1988;Campbell et al, 1989;Dunshea et al, 1993). This might be surprising as the genetic growth potential was markedly improved in the last decade due to breeding efforts.…”

Growth performance, carcass characteristics and meat quality of group-penned surgically castrated, immunocastrated (Improvac®) and entire male pigs and individually penned entire male pigs

“…In a recent study comparing the growth performance of group-penned entire males and barrows, we reported -E-mail: Giuseppe.Bee@alp.admin.ch that, entire males grew slower (774 v. 830 g/day), consumed less feed (1.88 v. 2.23 kg/day) but were more feed efficient (2.43 v. 2.69 kg feed/kg gain) than barrows (Pauly et al, 2008). The lower average daily feed intake (ADFI) and lower average daily gain (ADG) of entire males compared to barrows, is in agreement with Lawlor et al (2003) and Dunshea et al (2001) but in contrast to earlier results reported by Campbell et al (1989) and Dunshea et al (1993). Based on earlier observations (Pauly et al, 2008), it is unclear whether appetite is limiting or feed intake is low because of increased aggressive behaviour of group-penned entire males.…”

A solution to the problem of predicting the response of an animal to its diet

“…its genotype), which can be measured as described by Ferguson & Gous (1993). Any changes in the PR,,, due to administration of exogenous porcine somatotropin (for example Campbell et al 1989), or other pharmacological agents, are seen as changes in the values of these two variables, in particular the value of B.…”