Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
RESEARCH ARTICLE

Shearing Merino ewes at different stages of pregnancy: effects on fleece characteristics of progeny

E. H. van Reenen A , P. R. Kenyon B C , R. G. Sherlock B , R. E. Hickson B and S. T. Morris B
+ Author Affiliations
- Author Affiliations

A Ministry of Agriculture and Forestry, PO Box 2526, Wellington 6140, New Zealand.

B Sheep Research Centre, Massey University, PB 11-222, Palmerston North 4442, New Zealand.

C Corresponding author. Email: p.r.kenyon@massey.ac.nz

Animal Production Science 50(6) 603-607 https://doi.org/10.1071/AN09175
Submitted: 3 December 2009  Accepted: 14 April 2010   Published: 11 June 2010

Abstract

Shearing strong-wool ewes at different stages of pregnancy has been shown to influence the follicle population of the offspring which may result in a finer, heavier fleece. The aim of this study was to investigate the effect of shearing time of Merino ewes on the liveweight, fleece characteristics and follicle population of their progeny.

Pregnant Merino ewes were allocated to one of three shearing times; mid-pregnancy (d106; 106 days from the introduction of the ram), late-pregnancy (d141) and post-lambing (d191). A skin biopsy was taken from the mid-side of 128 lambs at d359 (~7 months of age) and analysed for primary and secondary follicle density. Mid-side wool samples were collected at d359, d499 and d716. Samples from d359 and d716 were analysed for washing yield, colour and fibre diameter. Greasy fleece weight was measured on d499 and a mid-side sample was taken to measure staple length and staple strength.

Shearing time of Merino ewes had no effect on lamb liveweight at any stage of the experiment. Lambs born to ewes shorn during pregnancy had a lesser (P < 0.05) follicle density, secondary follicle density, follicle number index (FNI) and secondary FNI than those born to ewes shorn post-lambing. However, there was no effect (P > 0.05) of dam shearing treatment on fleece characteristics of progeny. The results indicate that, under the conditions of this study shearing Merino ewes in mid-to-late pregnancy did not alter the fleece characteristics of their progeny.


Acknowledgements

We would like to acknowledge the financial support of the Vernon Willey Trust, the New Zealand Merino Co. Ltd, the Sinclair Cummings Trust and the Institute of Veterinary, Animal and Biomedical Sciences, Massey University and the on-farm support of Evan Gibson and Gus McAllister, Mt Grand, Wanaka.


References


Belschner HG, Carter HB, Turner HN (1937) Fleece characteristics of stud Merino sheep in relation to the degree of wrinkliness of the skin of the breech. III. Australian Veterinary Journal 13, 16–28.
Crossref | GoogleScholarGoogle Scholar | open url image1

Corbett JL (1979) Variation in wool growth with physiological state. In ‘Physiological and environmental limitations to wool growth’. (Eds JL Black, PJ Reis) pp. 79–98. (CSIRO: Sydney)

Dun RB, Grewal RS (1963) A comparison of the productive performance of single and twin born merino ewes. Australian Journal of Experimental Agriculture and Animal Husbandry 3, 235–242.
Crossref | GoogleScholarGoogle Scholar | open url image1

Fozi MA, Van der Werf JHJ, Swan AA (2007) Inclusion of skin follicle traits in selection indices in breeding programs improves genetic gain in Australian fine-wool Merinos. Australian Journal of Agricultural Research 58, 921–927.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hocking Edwards JE (1999) Reduction in wool follicles prior to birth in Merino sheep. Reproduction, Fertility and Development 11, 229–234.
Crossref | GoogleScholarGoogle Scholar | CAS | open url image1

Hocking Edwards JE, Birtles MJ, Harris PM, Parry AL, Paterson E, Wickham GA, McCutcheon SN (1996) Pre- and post-natal wool follicle development and density in sheep of five genotypes. Journal of Agricultural Science (Cambridge) 126, 363–370.
Crossref | GoogleScholarGoogle Scholar | open url image1

IWTO (1998) ‘Specification IWTO-47-98. Measurement of the mean and distribution of fibre diameter using an optical fibre diameter analyser (OFDA).’ (International Wool Secretariat: London)

Kenyon PR, Morris ST, Revell DK, McCutcheon SN (2002) Maternal constraint and the birthweight response to mid-pregnancy shearing. Australian Journal of Agricultural Research 53, 511–517.
Crossref | GoogleScholarGoogle Scholar | open url image1

Kenyon PR, Morel PCH, Morris ST (2004) Effect of ewe liveweight and condition score at mating and mid-pregnancy shearing on twin lamb birthweights and growth rates to weaning. New Zealand Veterinary Journal 52, 145–149.
CAS | PubMed |
open url image1

Kenyon PR, Sherlock RG, Morris ST, Morel PCH (2006) The effect of mid-and late-pregnancy shearing of hoggets on lamb birthweight, weaning weight, survival rate, and wool follicle and fibre characteristics. Australian Journal of Agricultural Research 57, 877–882.
Crossref | GoogleScholarGoogle Scholar | open url image1

Larsen JWA, Anderson N, Vizard AL, Anderson GA, Hoste H (1994) Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae. Australian Veterinary Journal 71, 365–372.
Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | open url image1

McCloghry CE (1997) Histological technique for the determination of wool follicle density. Wool Technology and Sheep Breeding 45, 129–145. open url image1

Nancarrow MJ, Nagorcka BN, Purvis IW (1998) Skin and follicle attributes contribute to differences in clean fleece weight in superfine Merino sheep. Animal Production in Australia. 22, 253–256. open url image1

Revell DK, Morris ST, Cottam YH, Hanna JE, Thomas DG, Brown S, McCutcheon SN (2002) Shearing ewes at mid-pregnancy is associated with changes in fetal growth and development. Australian Journal of Agricultural Research 53, 697–705.
Crossref | GoogleScholarGoogle Scholar | open url image1

SANZ (1984) ‘Method for the measurement of the colour of wool.’ NZS 8707, 1984. (Standards Association of New Zealand: Wellington)

Scobie DR, Young SR (2000) The relationship between wool follicle density and fibre diameter is curvilinear. Proceedings of the New Zealand Society of Animal Production 60, 162–165. open url image1

Scobie DR, Young SR, O’Connell D, Gurteen S (2005) Skin wrinkles affect wool characteristics and the time taken to harvest wool from Merino and halfbred sheep. New Zealand Journal of Agricultural Research 48, 177–185. open url image1

Sherlock RG, Kenyon PR, Morris ST (2002) Does mid-pregnancy shearing affect lamb fleece characteristics? Proceedings of the New Zealand Society of Animal Production 62, 57–60. open url image1

Smeaton DC, Webby RW, Tarbotton IS, Clayton JB (2000) The effects of shearing Finnish Landrace × Romney ewes in mid-pregnancy on lamb survival, birth weight and other weights. Proceedings of the New Zealand Society of Animal Production 60, 58–60. open url image1

van Reenen EH, Kenyon PR, Sherlock RG, Hickson RE, Morris ST (2008) Liveweight and body condition of single- and twin-bearing Merino ewes. Proceedings of the New Zealand Society of Animal Production 68, 67–68. open url image1