Sex and porcine somatotropin impact on variation in growth performance and back fat thickness
F. R. DunsheaDepartment of Primary Industries, 600 Sneydes Road, Werribee, Vic. 3030, Australia. Corresponding author. Email: Frank.Dunshea@dpi.vic.gov.au
Australian Journal of Experimental Agriculture 45(6) 677-682 https://doi.org/10.1071/EA04100
Submitted: 18 May 2004 Accepted: 25 November 2004 Published: 29 June 2005
Abstract
Managing variation in carcass weight and composition is an enormous challenge for the pig producer. A means of improving growth performance and reducing back fat is porcine exogenous somatotropin (pST) treatment. It is possible that this technology may also reduce variation in these important growth and carcass parameters. This study was conducted to provide data on the effect of sex and pST on variation in growth and carcass characteristics. Sixteen on-farm studies involving 1495 pigs were conducted in various states within Australia. On each farm, groups of pigs were randomly assigned within sex to one of 2 management regimes (control or pST regime). The control regime consisted of feeding the typical finisher diet used on that farm while the pST regime involved feeding the typical grower diet used on the farm combined with daily injections of pST (5 mg/day). Data from individual pigs were collated and the summary descriptive statistics derived for each treatment group on each farm were then analysed. Daily liveweight gain was lower and feed conversion ratio (FCR) and back fat at the P2 site were higher in gilts than in boars. The pST regime increased average mean daily gain and reduced feed intake, FCR and back fat at the P2 site. The coefficient of variation (CV) around live daily gain was lower in gilts than in boars (19.3 v 22.3% for gilts and boars, respectively, P<0.001) and in pigs treated with the pST regime (22.1 v. 19.9% for the control and pST regimes, respectively, P<0.001). The CV around liveweight was higher in the control boars than in any of the other treatment groups as indicated by the main (P<0.001) and interactive (P<0.001) effects of both sex and pST regime. The coefficient of variation around P2 was reduced by pST (16.2 v. 14.2%, P<0.001) but was not different between gilts and boars. There was an interaction (P = 0.025) between pST regime and sex with the average kurtosis for the P2 distribution positive in gilts treated with pST but slightly negative in all the other groups. The distributions were on average skewed to the right, particularly in gilts (P = 0.017) and in pigs treated with pST (P<0.001). In conclusion, these data demonstrate that as well as improving mean final liveweight and P2 back fat, pST treatment can also reduce variation in these key production parameters that form the basis for economic returns to the producer.
Additional keywords: pig, sex, feed intake.
Acknowledgments
The author is appreciative of the provision of Reporcin and collection of much of the data by Alpharma Animal Health technical field staff.
Campbell RG,
Johnson RJ,
King RH, Taverner MR
(1990) Effects of gender and genotype on the response of growing pigs to exogenous administration of porcine growth hormone. Journal of Animal Science 68, 2674–2681.
| Crossref |
PubMed |
Campbell RG,
Steele NC,
Caperna TJ,
McMurtry JP,
Solomon MB, Mitchell AD
(1989) Interrelationships between sex and exogenous growth hormone administration on performance, body composition and protein and fat accretion of growing pigs. Journal of Animal Science 67, 177–186.
| Crossref |
PubMed |
Cronin GM,
Dunshea FR,
Butler KL,
McCauley I,
Barnett JL, Hemsworth PH
(2003) The effects of immuno- and surgical-castration on the behaviour and consequently growth of group-housed, male finisher pigs. Applied Animal Behaviour Science 81, 111–126.
| Crossref | GoogleScholarGoogle Scholar |
Dunshea FR,
Colantoni C,
Howard K,
Jackson P,
Long KA,
Lopaticki S,
Nugent EA,
Simons JA,
Walker J, Hennessy DP
(2001) Vaccination of entire boars with Improvac eliminates boar taint and increases growth performance. Journal of Animal Science 79, 2524–2535.
| PubMed |
Dunshea FR,
Cox ML,
Borg MR,
Sillence MN, Harris DR
(2002) Porcine somatotropin (pST) administered using a commercial delivery system improves growth performance of rapidly-growing, group-housed finisher pigs. Australian Journal of Agricultural Research 53, 287–293.
| Crossref | GoogleScholarGoogle Scholar |
Dunshea FR,
Eason PJ,
King RH, Campbell RG
(1993) Effects of ractopamine, dietary energy and sex on protein and fat deposition in growing swine. Journal of Animal Science 71(Suppl. 1), 133.
Dunshea FR,
Kerton DK,
Cranwell PD,
Campbell RG,
Mullan BP,
King RH,
Power GN, Pluske JR
(2003) Lifetime and post-weaning determinants of performance indices of pigs. Australian Journal of Agricultural Research 54, 363–370.
| Crossref | GoogleScholarGoogle Scholar |
Dunshea FR,
King RH,
Eason PJ, Campbell RG
(1998) Interrelationships between dietary ractopamine, energy intake, and sex in pigs. Australian Journal of Agricultural Research 49, 565–574.
| Crossref | GoogleScholarGoogle Scholar |
King RH,
Campbell RG,
Smits RJ,
Morley WC,
Ronnfeldt K,
Butler K, Dunshea FR
(2000) Interrelationships between dietary lysine, sex, and porcine somatotropin administration on growth performance and protein deposition in pigs between 80 and 120 kg live weight. Journal of Animal Science 78, 2639–2651.
| PubMed |
McCauley I,
Watt M,
Suster D,
Kerton DJ,
Oliver WT,
Harrell RJ, Dunshea FR
(2003) A GnRF vaccine (Improvac (R)) and porcine somatotropin (Reporcin (R)) have synergistic effects upon growth performance in both boars and gilts. Australian Journal of Agricultural Research 54, 11–20.
| Crossref | GoogleScholarGoogle Scholar |
Oliver WT,
McCauley I,
Harrell RJ,
Suster D,
Kerton DJ, Dunshea FR
(2003) A gonadotropin-releasing factor vaccine (Improvac) and porcine somatotropin have synergistic and additive effects on growth performance in group-housed boars and gilts. Journal of Animal Science 81, 1959–1966.
| PubMed |
