Effect of hormonal growth promotant implants in weaner and hogget ewes on subsequent growth and reproductive performance
G. Bortolussi A B E , A. R. Bird A C , C. L. Playford D and J. Moore AA Department of Primary Industries Queensland, Julia Creek, Qld 4823, Australia.
B Present address: CSIRO Livestock Industries, PO Box 5545 Rockhampton Mail Centre, Qld 4702, Australia.
C Present address: CSIRO Division of Health Sciences and Nutrition, PO Box 10041, Adelaide, SA 5000, Australia.
D Department of Primary Industries Queensland, PO Box 6014, Rockhampton Mail Centre, Qld 4702, Australia.
E Author for correspondence: e-mail: greg.bortolussi@csiro.au
Australian Journal of Experimental Agriculture 44(8) 755-761 https://doi.org/10.1071/EA02097
Submitted: 27 May 2002 Accepted: 16 November 2003 Published: 17 September 2004
Abstract
Ninety young Merino ewes, depastured on Mitchell (Astrebla spp.) grass pastures in North West Queensland, were used in a hormonal growth promotant implantation study. The ewes were given 1 implant of Compudose, Ralgro, Revalor or Synovex-H, either at lamb marking (mid-dry season) or the start of the following summer wet season, which was ~180 days post-marking.
The hormonal growth promotant implanted groups had greater (P<0.05) liveweights than the control group early in the trial (days 22 and 57) and also from the end of the period of activity of the wet season implant (day 277) until the middle of the dry season (day 412). Dry season (at lamb marking) implantation did not improve average daily gain. From the end of the wet season onwards, ewes with a wet season implant were heavier (P<0.05) than those ewes implanted at lamb marking. This liveweight advantage had diminished by the start of the autumn mating. Hormonal growth promotant implantation had a favourable (P<0.05) effect on growth rate, but adversely affected reproduction in the ewes, regardless of time of implantation. Implantation with Compudose or Synovex-H significantly (P<0.001) reduced the demonstration of oestrus, while Revalor or Synovex-H reduced pregnancy rates by up to 100%. Despite Ralgro reducing these variables by up to 25%, its effect was not significant. All ewes that were diagnosed as pregnant at 140 days later produced lambs.
It was concluded from this study that hormonal growth promotant implantation at lamb marking provides no later-life advantage, while wet season implantation provides a growth or liveweight advantage to young Merino ewes and this persists for a long period after implantation. Despite the lack of an effect of Ralgro on oestrus and pregnancy results, however, implantation of young breeding ewes of any age should not be carried out, due to the long term and negative effects on reproductive performance. Wet season implantation may be best used for animals intended for slaughter.
Acknowledgments
The authors thank J. Bailey, A. Cotton, and S. Peart for their analytical and technical support of this experimental work. We also thank the manager and staff of ‘Toorak’ Research Station for their competent assistance with the experiment. Messrs. I. D. Loxton, R. A. Hunter, M. N. Sillence, J. Lindsay, G. Fordyce and M. D’Occhio are thanked for their advice and support regarding this study. We also thank R. Mayer and D. Reid for their valuable assistance with the experimental design and statistical analysis of the data.
Bass JJ,
Fowke PJ,
Duganzich DM, Paterson AJ
(1989) Effect of different doses of 17β-oestradiol on growth and carcass composition of wether and ewe lambs. Journal of Agricultural Science, Cambridge 113, 183–187.
| Crossref |
Bachman SE,
Galyean ML, Hallford DM
(1993) Influence of zeranol and cottonseed meal supplementation on performance by lambs fed prairie hay. Small Ruminant Research 10, 119–131.
| Crossref |
Bortolussi G, Bird AR
(1998) Effect of growth promotant implants on liveweight change, wool and carcass characteristics of mature wethers grazing dry season pastures. Australian Journal of Experimental Agriculture 38, 789–794.
| Crossref |
Cobon DH,
Connelly PT,
Bailey JV, Newman PA
(1994) Managing sheep for optimum productivity in astrebla pastures on north-west Queensland. Rangeland Journal 16, 39–50.
| Crossref |
Coelho JFS,
Galbraith H, Topps JH
(1981) The effect of a combination of trenbolone acetate and oestradiol-17β on growth performance and blood, carcass and body characteristics of wether lambs. Animal Production 32, 261–266.
Cooper RA
(1981) Some aspects of the use of the growth promoter Zeranol in ewe lambs retained for breeding. 1. Effect on liveweight gain and puberty. The British Veterinary Journal 137, 513–519.
| PubMed |
Cooper RA
(1981) Some aspects of the use of the growth promoter Zeranol in ewe lambs retained for breeding. 2. Effect on plasma LH levels. The British Veterinary Journal 137, 621–625.
| PubMed |
Cooper RA
(1985) Some aspects of the use of the growth promoter Zeranol in ewe lambs retained for breeding. 3. Effects on reproductive tract, pituitary gland and gonadotrophin levels. The British Veterinary Journal 141, 424–426.
| PubMed |
Deutscher GH,
Zerfos LL, Clanton DC
(1986) Time of zeranol implantation on growth, reproduction and calving of beef heifers. Journal of Animal Science , 875–886.
| PubMed |
Fitzsimons JM, Crosby TF
(1985) Growth and reproductive traits in lambs treated with oestradiol/progesterone and trenbolone acetate. Irish Journal of Agricultural Research 24, 195–200.
Galbraith H, Topps JH
(1981) Effect of hormones on the growth and body composition of animals. Nutrition Abstracts and Reviews 51, 521–539.
Hayden JM,
Bergen WG, Merkel RA
(1992) Skeletal muscle protein metabolism and serum growth hormone, insulin and cortisol concentrations in growing steers implanted with estradiol-17β plus trenbolone acetate. Journal of Animal Science 70, 2109–2119.
| PubMed |
Hess BW,
Lewis RH,
Stobart RH, Moss GE
(1998) Effects of zeranol on growth and reproductive performance on ewe lambs. Proceedings, Western Section, American Society of Animal Science 49, 319–322.
Hunter RA, Magner T
(1990) Effect of trenbolone acetate on urea metabolism in cattle fed low-protein roughage diets. Journal of Agricultural Science, Cambridge 114, 55–58.
| Crossref |
Hunter RA, Magner T
(1990) Whole body and tissue protein synthesis in steers losing weight on a low-protein roughage diet: the effect of trenbolone acetate. Journal of Agricultural Science, Cambridge 115, 121–127.
| Crossref |
Hunter RA, Vercoe JE
(1988) Effect of oestradiol-17β on energy metabolism of steers fed roughage diets. Journal of Agricultural Science, Cambridge 111, 187–190.
| Crossref |
Hunter RA,
Johnson CG, Frisch JE
(1993a) Effect of trenbolone acetate alone or in combination with oestradiol-17β for reducing weight loss in cattle. Australian Journal of Agricultural Research 44, 1113–1122.
| Crossref |
Hunter RA,
Sillence MN,
Gazzolla C, Spiers WG
(1993b) Increasing annual growth rates of cattle by reducing maintenance energy requirements. Australian Journal of Agricultural Research 44, 579–595.
| Crossref |
Hynd PI, James RE
(1987) The effect of trenbolone acetate and trenbolone acetate and oestradiol-17β on wool growth. Journal of Agricultural Science, Cambridge 108, 501–503.
| Crossref |
Kirkwood RN,
Cohen RDH,
King BD, Thacker PA
(1991) The influence of zeranol implantation on growth and reproduction in beef heifers. Canadian Journal of Animal Science 71, 1253–1256.
Lehman FD, Rains JR
(1996) Implants: a valuable tool for the cattle feeding industry. Food Animal Medicine and Management A Supplement to Compendium , 174–177.
Lorimer MS
(1981) Forage selection studies. 2. Diet quality, liveweight change and wool production of sheep grazing Astrebla spp. pastures in NW Queensland. Tropical Grasslands 15, 183–192.
Moran C,
Prediville DJ,
Quirke JF, Roche JF
(1990) Effects of oestradiol, zeranol or trenbolone acetate implants on puberty, reproduction and fertility in heifers. Journal of Reproduction and Fertility 89, 527–536.
| Crossref |
PubMed |
Rose M
(1972) Vital statistics for an experimental flock of merino sheep in north west Queensland. Proceedings of the Australian Society of Animal Production 9, 48–54.
Staigmiller RB,
Bellows RA, Short RE
(1983) Growth and reproductive traits in beef heifers implanted with zeranol. Journal of Animal Science 57, 527–534.
| PubMed |
Wilson LL,
Borger ML,
Paterson AD,
Rugh D, Orley CF
(1972) Effects of zeranol, dietary protein level and methionine hydroxy analogue on growth and carcass characters and certain blood metabolites in lambs. Journal of Animal Science 35, 128–131.
| PubMed |
