LH, FSH and testosterone variations were compared during the prepubertal period in Romanov and Ile-de-France ram lambs born in the spring. Mean plasma LH levels increased significantly between the 1st and 8th week of age in the Romanov and between the 1st and 12th week of age in the Ile-de-France. At 1 month of age, the number of LH and testosterone pulses per hour was higher in Romanov than in...

Prolific breeds of sheep (Romanov, Finn and Booroola Romanov crosses heterozygous for the Booroola gene (F+) were compared with breeds of lower prolificacy (Ile-de-France, Finn X Scottish Blackface, Merino X Blackface and Booroola X Romanov not carrying a copy of Booroola gene (++] by in-vivo monitoring of follicular kinetics by ink labelling during the late luteal phase and follicular phase of...

During terminal development of antral follicles, granulosa cells progressively lose their proliferative activity. Romanov (ovulation rate = 3) and Ile-de-France (ovulation rate = 1) breeds of sheep were compared for fractions of proliferating granulosa cells, determined by in vitro continuous [3H] thymidine labelling. In both breeds, the fraction of proliferating cells decreased with increasing...

Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed [Composite III (CIII) and northwestern whiteface (WF)], mating season (March and May), and their interactions on reproductive traits of mature F1 ewes in spring mating seasons. A total of 1,099 F1 ewes produced 1,754 litters of 2,995 lambs from exposures to Suffolk rams during March a...

The objective of this study was to evaluate the relationship between polymorphism at the MnlI site of MTNR1A gene and production traits of Shal and Romanov crossbreeding. The crossbreeding between Shal and Romanov was done on 600 Shal ewes. For this reason, Shal ewes were laparoscopically and artificially inseminated with the semen of Romanov breed. For the preparation of genomic DNA, a total o...

Pedigree information was analyzed in 7 small populations of sheep raised in France (Bleu du Maine, Charmoise, Cotentin, on-farm Romanov, Romanov ex situ in vivo, Roussin de la Hague, Solognote) to estimate their genetic variability. The pedigree information for each breed, estimated by the number of equivalent generations traced, ranged from rather poor (4.6) to very good (10.5) when compared w...

The objectives of this study were to evaluate intestinal cellularity and vascularity in mature ewes in response to dietary restriction and pregnancy status and to quantify the response of these variables to increased nutrient demand of fetal growth. In Exp. 1, 28 mature Dorset x crossbred white-faced ewes (61.6+/-1.8 kg initial BW) were fed a pelleted, forage-based diet. Treatments were arrange...

Remarkable seasonal variations are observed in the reproductive activities of small ruminants living in temperate latitudes (Luridiana et al. 2015). Thus, a great alteration is induced by lamb reproductive seasonality and its consequent meat market price. Alternatively, out-of-season reproduction is induced through a wide use of hormonal treatments in some countries. However, there is a need fo...

The five Northern European short-tailed sheep breeds present in North America are the Finnsheep, Romanov, Icelandic, Shetland and Gotland. The Finnsheep and Romanov were first imported in 1966 and 1986, respectively, for their high reproductive performance. The Shetland, Icelandic and Gotland breeds were first imported in 1980, 1985 and 2005, respectively, for the uniqueness of their physical a...