The effect of body condition and time of mating on the reproductive performance of Masham ewes

Abstract

Masham ewes were mated at three stages of the breeding season, early (15 September to 20 October), mid (20 October to 24 November) and late (15 December to 19 January), at two different body condition scores, 4 and 2, for 3 successive years. The mean scores achieved for body condition 4 were 3-6, 3-7 and 3-9 for early, mid and late respectively and for body condition 2 were 2-4, 2-3 and 2-2. In the late lambing flock more ewes were marked by vasectomized rams and less ewes were barren than in the early and mid flocks. The ewes in higher body condition at mating had significantly more triplets and fewer singles, and a higher lambing percentage (183 versus 165). This effect of body condition on litter size distribution was significant at each time of mating, with the ewes at the late mating producing significantly fewer triplets and more singles; this difference was caused by a reduction in the performance of the body condition 4 ewes in the late group. Young ewes in the body condition 4 group produced significantly fewer triplets and more singles than the mature ewes in the same body condition group, but at the lower body condition age had no effect on litter size distribution.

Review of sheep body condition score in relation to production characteristics

“…In contrast, other studies report a positive effect of BCS on the number of lambs born in Scottish Black Face , Masham (Newton et al 1980) and various other breeds (Pollott & Kilkenny 1976).…”

“…The end point from a reproductive perspective for farmers is often the numbers of lambs weaned per ewe presented for breeding. Kleemann et al (2006) in an across-flock analysis with Merino ewes, Newton et al (1980) with Masham ewes, and Saul et al (2011) with Merino ewes all reported that BCS at breeding and/or mid-pregnancy was positively correlated with the number of lambs weaned per ewe exposed to the ram. Vatankhah et al (2012), with Lori-Bakhtiari ewes, reported that BCS at breeding had a positive effect on the number of lambs weaned per ewe, but only to a BCS of 3.0 before it plateaued.…”

“…Therefore, it may not be surprising to suggest that a similar relationship would be observed for pregnancy rate. This may help to explain why no difference in pregnancy rates was observed between Masham ewes fed to maintain BCS of 2.0 or BCS of 4.0 (Newton et al 1980). Table 5).…”

“…Scottish Blackface ewes, with lower BCS, had a delayed start to the breeding season (Gunn & Doney 1975, Table 4), while late in the breeding season, Masham ewes with higher BCS were more likely to display oestrus (Newton et al 1980). Rasa Aragonesa ewes with higher BCS had a longer breeding season, predominately due to a later onset of seasonal anoestrous (Forcada et al 1992), and a shorter total seasonal anoestrous period (Rondon et al 1996).…”

Relationship Between Ewe Body Condition Score (Bcs) at Breeding Season and Reproductive Traits

“…Çalışmada bulunan sonuçlar Gibb and Treacher (1982), Litherland et al, (1999), Thompson et al, (2011);Al-Sabbagh et al, (1995), Aliyari et al, (2012), Verbeek et al, (2012) ile benzer; Gibb and Treacher (1980), Kenyon et al, (2004), Kenyon et al, (2011), Mathias-Davis et al, (2013 ve Molina et al, (1991) Merinoslarda (McInnes and Smith 1966), Suffolk ırkında (Rozeboom et al, 2007) ve İvesi ırkında (Aliyari et al, 2012) yapılan çalışmalarda VKS ile fertilite ve litter size arasında ilişki olmadığı belirtilmiştir. Ancak bu durumun aksini iddia eden çalışmalarda mevcuttur Newton et al, 1980;Geisler and Fenlon 1979).…”