The Animal Biology

INDICES OF RENEWAL OF EWE SEXUAL ACTIVITY AND ITS CORRELATION WITH AGE, WEIGHT, TRADITIONAL REPRODUCTIVE TRAITS AND CLIMATIC CONDITIONS

I. V. Lobachova, O. V. Ivanyna

This email address is being protected from spambots. You need JavaScript enabled to view it.

Institute of Animal Husbandry in Steppe Regions “Ascania-Nova” named after M. F. Ivanov’s —
National Scientific Selection-Genetic Centre of Sheep Breeding,
1 Soborna str., Ascania-Nova, Chaplynskyy district, Kherson region, 75230, Ukraine

To evaluate the quality of renewal of the sexual activity in ewes during the insemination campaign next indices were developed: IH_i — the index of heat (0 or 1), IHT_i — the index of heat time (from 1 to 4), ICT_i — the index of conception time (from 1 to 4) and IL_i — the index of lambing (from 0 to 3). Relationships between the indices and age, weight, part of animals with the heat (E%), fertility (F%), fecundity (Fm%), prolificacy (Pf) and climatic condition were researched. Data of Ascanian Merino ewes of 6 years was used.

Dependences between the indices and age, weight, change of weight and reproduction traits were non-linear. The IH_i index was increasing with the rise of age, but after 6 years began to decrease. The mean IHT_i index was the highest in the youngest and oldest animals indicating that the first heat delays in ewe lambs and ≥8-years old animals. Change of the ICT_i index showed that the youngest and oldest animals had the lowest success to become pregnant during the first heat. Level of correlation between the weight and its change from the one side and the indices from the other was high (R>0.7) in young (≥2 years old) and moderate–noticeable (0.3<R<0.7) in more aged animals. The IHT_i index had noticeable relationship with E%, F%, Fm% and low (R<0.3) with Pf, the ICT_i index — high with F% and Fm% and low with Pf. The IHT_i index reliably negatively correlated with the average air temperature in May and June, the ICT_i and IL_i — with mean temperature in July. The average humidity in June reliably positively correlated with E%, in July — with Pf.

It was supposed that the created indices may be useful to evaluate the efficiency of the applying of technological and selection approaches allowed to reducing of seasonality of sheep reproduction.

Keywords: EWE, REPRODUCTION, SEXUAL ACTIVITY, INDEX

1. Aktaş A. H., Dursun Ş., Doğan Ş., Kiyma Z., Demirci U., Halıcı İ. Effects of ewe live weight and age on reproductive performance, lamb growth, and survival in Central Anatolian Merino sheep. Arch. Anim. Breed, 2015, vol. 58, issue 2, pp. 451–459. https://doi.org/10.5194/aab-58-451-2015
2. Bartlewski P. M., Beard A. P., Cook S. J., Rawlings N. C. Ovarian follicular dynamics during anoestrus in ewes. J. Repr. Fert., 1998, vol. 113, pp. 275–285. https://doi.org/10.1530/jrf.0.1130275
3. Cameron J., Malpaux B., Castonguay F. W. Accelerated lambing achieved by a photoperiod regimen consisting of alternating 4-month sequences of long and short days applied year-round. J. Anim. Sci., 2010, vol. 88, issue 10, pp. 3280–3290. https://doi.org/10.2527/jas.2010-2911
4. Chanvallon A., Sagot L., Pottier E., Scaramuzzi R. J., Fabre-Nys C. Interactions among seasonality of reproduction, genotype and the ram effect. Archiva Zootechnica, 2009, vol. 12, no. 3, pp. 73–81.
5. Eteqadi B., Ghavi Hossein-Zadeh N., Shadparvar A. A. Genetic analysis of basic and composite reproduction traits in Guilan sheep. Ann. Anim. Sci., 2017, vol. 17, issue 1, pp. 105–116. https://doi.org/10.1515/aoas-2016-0016
6. Gushwa W. T., Bradford G. E., Stabenfeldtt G. H., Berger Y. M., Dally M. R. Ram influence on ovarian and sexual activity in anestrous ewes: effects of isolation of ewes from rams before joining and date of ram introduction. J. Anim. Sci., 1992, vol. 70, issue 4, pp. 1195–1200. https://doi.org/10.2527/1992.7041195x
7. Karsch F. J., Bittman E. L., Foster D. L., Goodman R. L., Legan S. J., Robinson J. E. Neuroendocrine basis of seasonal reproduction. Recent Prog. Hor. Res., 1984, vol. 40, pp. 185–232. https://doi.org/10.1016/B978-0-12-571140-1.50010-4
8. Lobachova I. V. Ovary morphology in ewes in different months of year. The Animal Biology, 2016, vol. 18, no. 1, pp. 77–86. (in Ukrainian) https://doi.org/10.15407/animbiol18.01.077
9. Lôbo A. M. B. O., Lôbo R. N. B., Paiva S. R., Oliveira de S. M. P., Facó O. Genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population. Genet. Mol. Biol., 2009, vol. 32, no. 4, pp. 761–770. https://doi.org/10.1590/S1415-47572009005000080
10. O’Ferrall M. G. J. A comparison of sheep breeds and crosses for ewe productivity. Ir. J. Agric. Res., 1975, vol. 14, no. 3, pp. 285–296.
11. Notter D. R., Copenhaver J. S. Performance of Finnish Landrace crossbred ewes under accelerated lambing. I. Fertility, prolificacy and ewe productivity. J. Anim. Sci., 1980, vol. 51, issue 5, pp. 1033–1042. https://doi.org/10.2527/jas1980.5151033x
12. Notter D. R. Genetic aspects of reproduction in sheep. Repr. Domestic Anim., 2008, vol. 43, issue s2, pp. 122–128. https://doi.org/10.1111/j.1439-0531.2008.01151.x
13. Notter D. R. Genetic improvement of out-of-season breeding through selection. In: D. G. Morrical (ed.) Out of Season Breeding Symposium. Iowa State Univ., Ames., 1992, pp. 55–81.
14. Notter D. R., Smith J. K., Akers R. M. Patterns of estrous cycles, estrous behavior, and circulating prolactin in spring and summer in ewes selected for autumn lambing and exposed to ambient or long-day photoperiods. Appl. Anim. Behav. Sci., 2011, vol. 129, issue 1–2, pp. 30–36. https://doi.org/10.1016/j.anireprosci.2011.10.008
15. Oldham C. M., Martin G. B. Stimulation of seasonally anovular Merino ewes by rams II: Premature regression of ram-induced corpora lutea. Anim. Reprod. Sci., 1978, vol. 1, issue 4, pp. 291–295. https://doi.org/10.1016/0378-4320(79)90014-9
16. Ptáček M., Ducháček J., Stádník L., Fantová M. Effects of age and nutritional status at mating on the reproductive and productive traits in Suffolk sheep kept under permanent outdoor management system. Czech J. Anim. Sci., 2017, vol. 62, pp. 211–218. https://doi.org/10.17221/63/2016-CJAS
17. Rubaines E., Menchaca A., Gil J., Olivera J. Reproductive performance of a new timed artificial insemination protocol (Synchrovine™) in sheep. Repr. Fert. Dev., 2004, vol. 16, p. 508.
18. Sawyer G. J., Lindsay D. R., Martin G. R. The Influence of radiant heat load on reproduction in the merino ewe. III Duration of oestrus, cyclical oestrous activity, plasma progesterone, LH levels and fertility of ewes exposed to high temperatures before mating. Aust. J. Agric. Res., 1979, vol. 30, no. 6, pp. 1151–1162. https://doi.org/10.1071/AR9791151

Download full text in PDF