Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-28T04:07:31.141Z Has data issue: false hasContentIssue false
  • English
  • Français

Selection for superior growth advances the onset of puberty and increases reproductive performance in ewe lambs

Published online by Cambridge University Press:  08 February 2013

C. A. Rosales Nieto ,
M. B. Ferguson ,
C. A. Macleay ,
J. R. Briegel ,
G. B. Martin  and
A. N. Thompson
C. A. Rosales Nieto
Affiliation:
CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia Department of Agriculture and Food of Western Australia, 3 Baron Hay Court, South Perth, Western Australia 6151, Australia Institute of Agriculture, University of Western Australia, Crawley, Western Australia 6009, Australia
M. B. Ferguson
Affiliation:
CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia Department of Agriculture and Food of Western Australia, 3 Baron Hay Court, South Perth, Western Australia 6151, Australia School of Veterinary and Biomedical Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
C. A. Macleay
Affiliation:
Department of Agriculture and Food of Western Australia, 3 Baron Hay Court, South Perth, Western Australia 6151, Australia
J. R. Briegel
Affiliation:
Department of Agriculture and Food of Western Australia, 3 Baron Hay Court, South Perth, Western Australia 6151, Australia
G. B. Martin
Affiliation:
Institute of Agriculture, University of Western Australia, Crawley, Western Australia 6009, Australia
A. N. Thompson*
Affiliation:
CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia Department of Agriculture and Food of Western Australia, 3 Baron Hay Court, South Perth, Western Australia 6151, Australia School of Veterinary and Biomedical Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
*
†E-mail: [email protected]
Get access

Abstract

The reproductive efficiency of the entire sheep flock could be improved if ewe lambs go through puberty early and produce their first lamb at 1 year of age. The onset of puberty is linked to the attainment of critical body mass, and therefore we tested whether it would be influenced by genetic selection for growth rate or for rate of accumulation of muscle or fat. We studied 136 Merino ewe lambs with phenotypic values for depth of eye muscle (EMD) and fat (FAT) and Australian Sheep Breeding Values at post-weaning age (200 days) for live weight (PWT), eye muscle depth (PEMD) and fat depth (PFAT). First oestrus was detected with testosterone-treated wethers and then entire rams as the ewes progressed from 6 to 10 months of age. Blood concentrations of leptin and IGF-I were measured to test whether they were related to production traits and reproductive performance (puberty, fertility and reproductive rate). In total, 97% of the lambs reached first oestrus at average weight 39.4 ± 0.4 kg (mean ± s.e.m.) and age 219 days (range 163 to 301). Age at first oestrus decreased with increases in values for PWT (P < 0.001), and concentrations of IGF-I (P < 0.05) and leptin (P < 0.01). The proportion of ewe lambs that achieved puberty was positively related with increases in values for EMD (P < 0.01), FAT (P < 0.05) or PWT (P < 0.01), and 75% of the ewe lambs were pregnant at average weight 44.7 ± 0.5 kg and age 263 days (range 219 to 307). Ewe lambs that were heavier at the start of mating were more fertile (P < 0.001) and had a higher reproductive rate (P < 0.001). Fertility and reproductive rate were positively correlated with increases in values for EMD (P < 0.01), FAT (P < 0.05), PWT (P < 0.01) and leptin concentration (P < 0.01). Fertility, but not reproductive rate, increased as values for PFAT increased (P < 0.05). Leptin concentration increased with increases in values for EMD (P < 0.001), FAT (P < 0.001), PWT (P < 0.001), PEMD (P < 0.05) and PFAT (P < 0.05). Many of these relationships became non-significant when PWT or live weight was added to the statistical model. We conclude that selection for genetic potential for growth can accelerate the onset of puberty and increase fertility and reproductive rate of Merino ewe lambs. The metabolic hormones, IGF-I and leptin, might act as a physiological link between the growing tissues and the reproductive axis.

Keywords

ewe lambsphenotypic selectionASBVreproductive efficiency
Type
Physiology and functional biology of systems
Information
animal , Volume 7 , Issue 6 , June 2013 , pp. 990 - 997
Copyright
Copyright © The Animal Consortium 2013

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alkass, JE, Aziz, DA, Al-Nidawi, KA 1994. Genetic aspects of puberty in Awassi ewes. Small Ruminant Research 14, 249–252.Google Scholar
Barlow, R, Hodges, C 1976. Reproductive performance of ewe lambs: genetic correlation with weaning weight and subsequent reproductive performance. Australian Journal of Experimental Agriculture 16, 321–324.Google Scholar
Blache, D, Tellam, RL, Chagas, LM, Blackberry, MA, Vercoe, P, Martin, GB 2000. Level of nutrition affects leptin concentrations in plasma and cerebrospinal fluid in sheep. Journal of Endocrinology 165, 625–637.CrossRefGoogle ScholarPubMed
Boulanouar, B, Ahmed, M, Klopfenstein, T, Brink, D, Kinder, J 1995. Dietary protein or energy restriction influences age and weight at puberty in ewe lambs. Animal Reproduction Science 40, 229–238.CrossRefGoogle Scholar
Breier, BH, Gallaher, BW, Gluckman, PD 1991. Radioimmunoassay for insulin-like growth factor-I: solutions to some potential problems and pitfalls. Journal of Endocrinology 128, 347–357.Google Scholar
Brown, DJ, Huisman, AE, Swan, AA, Graser, HU, Woolaston, RR, Ball, AJ, Atkins, KD, Banks, RG 2007. Genetic evaluation for the Australian sheep industry. In Proceedings of the Association for the Advancement of Animal Breeding and Genetics 17, 187–194.Google Scholar
Cave, LM, Kenyon, PR, Morris, ST 2012. Effect of timing of exposure to vasectomised rams and ewe lamb body condition score on the breeding performance of ewe lambs. Animal Production Science 52, 471–477.Google Scholar
Chilliard, Y, Delavaud, C, Bonnet, M 2005. Leptin expression in ruminants: nutritional and physiological regulations in relation with energy metabolism. Domestic Animal Endocrinology 29, 3–22.CrossRefGoogle ScholarPubMed
Dýrmundsson, ÓR 1973. Puberty and early reproductive performance in sheep. I. Ewe lambs. Animal Breeding Abstracts, 273–289.Google Scholar
Dýrmundsson, ÓR 1981. Natural factors affecting puberty and reproductive performance in ewe lambs: a review. Livestock Production Science 8, 55–65.Google Scholar
Ferguson, MB, Adams, NR, Robertson, IRD 2007. Implications of selection for meat and wool traits on maternal performance in Merinos. In Proceedings of the Association for the Advancement of Animal Breeding and Genetics 17, 195–198.Google Scholar
Ferguson, MB, Kennedy, AJ, Young, JM, Thompson, AN 2011. The roads to efficiency in the ewe flock. In Recent Advances in Animal Nutrition – Australia 18, 37–42.Google Scholar
Ferguson, MB, Young, JM, Kearney, GA, Gardner, GE, Robertson, IRD, Thompson, AN 2010. The value of genetic fatness in Merino ewes differs with production system and environment. Animal Production Science 50, 1011–1016.Google Scholar
Foster, DL, Nagatani, S 1999. Physiological perspectives on leptin as a regulator of reproduction: role in timing puberty. Biology of Reproduction 60, 205–215.CrossRefGoogle ScholarPubMed
Foster, DL, Yellon, SM, Olster, DH 1985. Internal and external determinants of the timing of puberty in the female. Journal of Reproduction and Fertility 75, 327–344.CrossRefGoogle ScholarPubMed
Gluckman, PD, Johnson–Barrett, JJ, Butler, JH, Edgar, BW, Gunn, TR 1983. Studies of insulin-like growth factor-I and -II by specific radioligand assays in umbilical cord blood. Clinical Endocrinology 19, 405–413.Google Scholar
Hafez, ESE 1952. Studies on the breeding season and reproduction of the ewe Part I. The breeding season in different environments Part II. The breeding season in one locality. Part III. The breeding season and artificial light Part IV. Studies on the reproduction of the ewe Part V. Mating behaviour and pregnancy diagnosis. The Journal of Agricultural Science 42, 189–265.Google Scholar
Hare, L, Bryant, MJ 1985. Ovulation rate and embryo survival in young ewes mated either at puberty or at the second or third oestrus. Animal Reproduction Science 8, 41–52.CrossRefGoogle Scholar
Hawker, H, Kennedy, J 1978. Puberty and subsequent oestrous activity in young Merino ewes. Australian Journal of Experimental Agriculture and Animal Husbandry 18, 347–354.Google Scholar
Huisman, AE, Brown, DJ 2009. Genetic parameters for bodyweight, wool, and disease resistance and reproduction traits in Merino sheep. 3. Genetic relationships between ultrasound scan traits and other traits. Animal Production Science 49, 283–288.Google Scholar
Kenyon, PR, Morris, ST, West, DM 2010. Proportion of rams and the condition of ewe lambs at joining influences their breeding performance. Animal Production Science 50, 454–459.Google Scholar
Kleemann, DO, Walker, SK 2005. Fertility in South Australian commercial Merino flocks: relationships between reproductive traits and environmental cues. Theriogenology 63, 2416–2433.CrossRefGoogle ScholarPubMed
Malau-Aduli, AEO, Bond, GH, Dunbabin, M 2007. Influence of body weight and body condition score at breeding on conception and prolificacy of Merino and Composite Coopworth, East Friesian, Romney and Texel sheep in Tasmania, Australia. Journal of Animal Science 85 (suppl. 1), 663.Google Scholar
Martin, GB, Durmic, Z, Kenyon, PR, Vercoe, PE 2009. Landcorp lecture: ‘Clean, green and ethical’ animal reproduction: extension to sheep and dairy systems in New Zealand. In Proceedings of the New Zealand Society of Animal Production 69, 140–147.Google Scholar
McGuirk, BJ, Bell, AK, Smith, MD 1968. The effect of bodyweight at joining on the reproductive performance of young crossbred ewes. In Proceedings of the Australian Society of Animal Production 7, 220–222.Google Scholar
McMillan, WH, McDonald, MF 1985. Survival of fertilized ova from ewe lambs and adult ewes in the uteri of ewe lambs. Animal Reproduction Science 8, 235–240.Google Scholar
Roberts, CA, McCutcheon, SN, Blair, HT, Gluckman, PD, Breier, BH 1990. Developmental patterns of plasma insulin-like growth factor-I concentrations in sheep. Domestic Animal Endocrinology 7, 457–463.CrossRefGoogle ScholarPubMed
SAS Institute 2010. SAS/Stat user's guide, version 9.3. SAS Institute Inc., Cary, NC, USA.Google Scholar
Smith, GD, Jackson, LM, Foster, DL 2002. Leptin regulation of reproductive function and fertility. Theriogenology 57, 73–86.CrossRefGoogle ScholarPubMed
Southam, ER, Hulet, CV, Botkin, MP 1971. Factors influencing reproduction in ewe lambs. Journal of Animal Science 33, 1282–1287.CrossRefGoogle Scholar
Quirke, JF 1981. Regulation of puberty and reproduction in female lambs: a review. Livestock Production Science 8, 37–53.Google Scholar