Effect of the Feed Level on the Seasonality of the Sexual Activity of Timahdite Ewes: Role of the Leptin and IGF System

The effects of the feed level on the seasonality of the sexual activity were studied in Timahdite ewes in the Middle Atlas region of Morocco (33°N). Non pregnant and non lactating adult ewes (3-4 years) were allocated to two groups according to two diet levels: HL (n = 10) received double the maintenance requirements and LL (n = 9) the maintenance requirements. Over a one-year period, estrus was recorded twice daily and blood samples were collected weekly to determine progesterone, leptin, IGF-1, IGFBP-2 and IGFBP-3 plasmatic levels. The higher feed level stimulated the reproductive activity in HL ewes, which presented a longer reproductive season and a significantly higher number of normal estrous cycles than LL ewes (7.8 ± 1.4 vs 3.9 ± 1.9, respectively; P 0.05). These results showed that the Timahdite ewe exhibited a seasonal reproductive pattern which was modulated by the feed level

Body weight, oestrous and ovarian activity in local Burundian ewes and goats after parturition in the dry season

To compare body weight losses and post-partum anoestrus, twelve local Burundian ewes and twelve goats which had lambed or kidded at the middle of the dry season were followed from parturition until eight months. Each dam was weighed every month and bled three times a week to assess the ovarian activity resumption by plasma progesterone (P4) profiles. For the two species, the body weight decreased significantly (

Sensitivity of follicles from prepubertal calves ovaires to in vitro stimulation with LH and FSH

Ovaries from prepubertal calves were harvested in an abattoir and quickly brought to the laboratory for the dissection of the follicles. The intact entire follicles were put in individual chambers and continuously perifused with TCM199 at the rate of 1ml/30 min. The medium was added LH at the time 60–90 min and FSH at the time 120–180 min. The perifusion lasted 5 hours and the perifused medium was collected every 30 min. The samples were assayed for Progesterone, D4-Androstenedione and Estradiol. Four different stimulations were assayed: LH +FSHc (FSH commercial with an estimated 20% LH contamination), LH + FSHp (pure FSH, with 0% LH activity), FSHc alone, and FSHp alone. No difference were observed between the treatments; this confirms the results of De Roover eet al. (this workshop) that the absence of LH is not the reason for the lack of Estradiol peak after FSH stimulation of calves ovaries in vivo. Only large follicles (diameter ³ 13 mm) were able to produce Estradiol in vitro. According to the follicular size, no difference can be measured in D4 production, but medium sized follicles produced significantly more Progesterone than small or large ones. It can be interpreted as a growing ability to produce Progesterone and the late acquisition of ability to produce Estradiol. The observation of the small proportion of follicles with diameter ³ 13 mm may be the explanation of the lack of E2 peak production after in vivo stimulation. High levels of Estradiol are suspected to be necessary for the acquisition of the oocyte competency to develop into viable embryos. The incapability of most of the follicles present in ovaries of prepubertal calves to produce significant level of E2 might be the reason of the poor results in embryo development after ovum pick-up in this kind of animal

Pre-ovulatory follicular characteristics and ovulation rates in different breed crosses, carriers or non-carriers of the Booroola or Cambridge fecundity gene

Terminal follicular dynamics and ovulation rates (OR) were compared in different local breeds after introducing fecundity genes of different origin. Crossbred ewes which were carriers (F +) or non-carriers (+ +) of Booroola ((B)Fec) or Cambridge genes ((C)Fec) were included: Cambridge x Cambridge (CC), Cambridge x Suffolk (CS), Cambridge x Texel (CT), Booroola x Texel (BT) and Booroola x German Mutton Merino (BGM). The numbers of small (diameter 2-3.5 mm), medium (diameter > 3.5-5.0 mm) and large (diameter > 5.0 mm) growing follicles, the maximum diameter before ovulation and the regression and artesia rates of ovarian follicles ≥ 2 mm in diameter were studied laparoscopically and repeatedly during the last 5 days of an induced oestrous cycle. The ORs were determined one cycle before and two cycles after the repeated laparoscopy. (B)Fec and (C)Fec significantly enhanced the OR of all crossbreeds. Carriers of (B)Fec or (C)Fec did not have significantly different ORs due to any crossbreeding effect. The same observation was made for non-carriers of both Fec gene types. Whatever the crossbreed, the number of small, medium and large growing follicles were similar between carriers and non-carriers in spite of a higher number of ovulating follicles in carriers of both Fec gene types. The diameter of ovulatory follicles did not differ among crossbreds, or between carriers and non-carriers except in the BT (5.2 ± 0.2 vs. 6.5 ± 0.8 mm, respectively) and CC (6.6 ± 0.2 vs. 5.6 ± 0.3 mm) ewes. The higher OR in the presence of the Booroola gene was associated with a low atresia rate of large follicles in all crossbreeds (BT: 52 ± 8% (F +) vs. 61 ± 7% (+ +); BGM: 51 ± 6% vs. 75 ± 5%). The high OR of the carriers of the (C)Fec gene seemed to be associated with a lower number of large growing follicles with a lower (P < 0.05) atresia rate as compared with Booroola crossbreeds. In conclusion, follicular features were similar between purebred Cambridge and its crossbred CS and CT. In ewes carrying the (B)Fec or (C)Fec gene, the reduction in follicular atresia seemed to be one of the main follicular features implicated in the higher OR. (C) 2000 Elsevier Science B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Pre-ovulatory follicular characteristics and ovulation rates in different breed crosses, carriers or non-carriers of the Booroola or Cambridge fecundity gene

Terminal follicular dynamics and ovulation rates (OR) were compared in different local breeds after introducing fecundity genes of different origin. Crossbred ewes which were carriers (F +) or non-carriers (+ +) of Booroola ((B)Fec) or Cambridge genes ((C)Fec) were included: Cambridge x Cambridge (CC), Cambridge x Suffolk (CS), Cambridge x Texel (CT), Booroola x Texel (BT) and Booroola x German Mutton Merino (BGM). The numbers of small (diameter 2-3.5 mm), medium (diameter > 3.5-5.0 mm) and large (diameter > 5.0 mm) growing follicles, the maximum diameter before ovulation and the regression and artesia rates of ovarian follicles ≥ 2 mm in diameter were studied laparoscopically and repeatedly during the last 5 days of an induced oestrous cycle. The ORs were determined one cycle before and two cycles after the repeated laparoscopy. (B)Fec and (C)Fec significantly enhanced the OR of all crossbreeds. Carriers of (B)Fec or (C)Fec did not have significantly different ORs due to any crossbreeding effect. The same observation was made for non-carriers of both Fec gene types. Whatever the crossbreed, the number of small, medium and large growing follicles were similar between carriers and non-carriers in spite of a higher number of ovulating follicles in carriers of both Fec gene types. The diameter of ovulatory follicles did not differ among crossbreds, or between carriers and non-carriers except in the BT (5.2 ± 0.2 vs. 6.5 ± 0.8 mm, respectively) and CC (6.6 ± 0.2 vs. 5.6 ± 0.3 mm) ewes. The higher OR in the presence of the Booroola gene was associated with a low atresia rate of large follicles in all crossbreeds (BT: 52 ± 8% (F +) vs. 61 ± 7% (+ +); BGM: 51 ± 6% vs. 75 ± 5%). The high OR of the carriers of the (C)Fec gene seemed to be associated with a lower number of large growing follicles with a lower (P < 0.05) atresia rate as compared with Booroola crossbreeds. In conclusion, follicular features were similar between purebred Cambridge and its crossbred CS and CT. In ewes carrying the (B)Fec or (C)Fec gene, the reduction in follicular atresia seemed to be one of the main follicular features implicated in the higher OR. (C) 2000 Elsevier Science B.V