Reproductive performance of ewes treated with an estrus induction/synchronization protocol during the spring season

The aim of this study was to evaluate the reproductive performance of ewes treated with eCG and an exogenous progestagen protocol during the spring season. Forty - eight mixed - breed wool and hair ewes ( body condition score of 2.8 ± 0.5 and 41 ± 3 kg ) were randomly assigned into two groups ( n = 24/group), which received (G - Sync) or not (G - Control) an intravaginal device ( Day 0) containing 60 mg of medroxyprogesterone acetate. On D ay 7, ewes of the G - Sync were injected with 300 IU of eCG and 30 ug of d - C loprostenol, im . On D ay 9, the device was removed and 12 h later males were introduced into the G - Sync and G - Control groups in a proportion of 1:6. Estrus response observation and mating were performed during D ays 10, 11 and 12 from 7 to 9 AM and 4 to 6 PM. After D ay 12, males were s eparated from females for 10 days and later reintroduced into the flock for 45 days. Estrus rates for the G - Control and G - Sync group s during D ays 10, 11 and 12 were 4 and 88 % (P < 0.05) , respectively . Pregnancy rates fr om initial mating on D ays 10, 11 and 12 were 0 (G - Control) and 4 6% (G-Sync;P < 0.05). Total pregnancy rates for the whole mating season were 50 (G-Control) and 79% (G-Sync;P< 0.05). The exogenous progestagen protocol plus eCG used for estrus induction/s ynchronization improved the pregnancy rate of mixed-breed wool and hair ewes by about 29% points at the end of the breeding season. Thus, this procedure seems to be appropriate to be implemented as part of the reproductive management of some ovine farms during the non-breeding season.

Reproductive performance of ewes treated with an estrus induction/synchronization protocol during the spring season

The aim of this study was to evaluate the reproductive performance of ewes treated with eCG and an exogenous progestagen protocol during the spring season. Forty - eight mixed - breed wool and hair ewes ( body condition score of 2.8 ± 0.5 and 41 ± 3 kg ) were randomly assigned into two groups ( n = 24/group), which received (G - Sync) or not (G - Control) an intravaginal device ( Day 0) containing 60 mg of medroxyprogesterone acetate. On D ay 7, ewes of the G - Sync were injected with 300 IU of eCG and 30 ug of d - C loprostenol, im . On D ay 9, the device was removed and 12 h later males were introduced into the G - Sync and G - Control groups in a proportion of 1:6. Estrus response observation and mating were performed during D ays 10, 11 and 12 from 7 to 9 AM and 4 to 6 PM. After D ay 12, males were s eparated from females for 10 days and later reintroduced into the flock for 45 days. Estrus rates for the G - Control and G - Sync group s during D ays 10, 11 and 12 were 4 and 88 % (P < 0.05) , respectively . Pregnancy rates fr om initial mating on D ays 10, 11 and 12 were 0 (G - Control) and 4 6% (G-Sync;P < 0.05). Total pregnancy rates for the whole mating season were 50 (G-Control) and 79% (G-Sync;P< 0.05). The exogenous progestagen protocol plus eCG used for estrus induction/s ynchronization improved the pregnancy rate of mixed-breed wool and hair ewes by about 29% points at the end of the breeding season. Thus, this procedure seems to be appropriate to be implemented as part of the reproductive management of some ovine farms during the non-breeding season.(AU)

Effect of indole acetic acid on the in vitro activation and survival of bovine (Bos indicus) preantral follicles

The objective of this study was to evaluate the development of preantral follicles from the Nelore breed of Bos indicus after in vitro culture of ovarian cortices in different concentrations of indole acetic acid (IAA). In addition, this study investigated the possible association of mammalian genes with IAA activity in bovine preantral follicles using an in silico approach. Ovaries (N = 8) from Nelore heifers were collected, and the ovarian cortex was divided into 14 fragments were cultured individuallu for two or siz days in Minimum Essential Medium (MEM) with 0, 10, 40, 100, 500 or 1000 ng/ml of IAA. Follicles were classified as primordial or as developing (primary and secondary) follicles. The in silico approach to search for auxinresponsive candidate genes was performed with bioinformaties tools, such as GenBank and SWISS-PROT database, Kyoto Encyclopedia of Genes and Genomes (KEGG) and the Clustal W program. Compared to the control culture, the percentage of primordial follicles was reduced (P < 0,05) and the percentage of developing follicles was increased ( P < 0,05) after 2 or 6 days of culture in all media tested. Furtherimore, culture of the ovarian cortex for 6 days reduced the percentage of healthy, morphologically normal follicles when compared with the control (P < 0,05). In contrast, cultures supplemented with 10 ng/ml of IAA were the only samples that had similar (P < 0,05) percentages relative to the control group. Finally, we found a mammalian gene that was homologous to the plant gene, ROOTY, which may be involved in the oocyte response to IAA. We conclude that the 10 ng/ml concentration of IAA promoted follicular survival and activation of nelore bovine preantral follicles after 6 days of culture in vitro.(AU)

Effect of indole acetic acid on the in vitro activation and survival of bovine (Bos indicus) preantral follicles

The objective of this study was to evaluate the development of preantral follicles from the Nelore breed of Bos indicus after in vitro culture of ovarian cortices in different concentrations of indole acetic acid (IAA). In addition, this study investigated the possible association of mammalian genes with IAA activity in bovine preantral follicles using an in silico approach. Ovaries (N = 8) from Nelore heifers were collected, and the ovarian cortex was divided into 14 fragments were cultured individuallu for two or siz days in Minimum Essential Medium (MEM) with 0, 10, 40, 100, 500 or 1000 ng/ml of IAA. Follicles were classified as primordial or as developing (primary and secondary) follicles. The in silico approach to search for auxinresponsive candidate genes was performed with bioinformaties tools, such as GenBank and SWISS-PROT database, Kyoto Encyclopedia of Genes and Genomes (KEGG) and the Clustal W program. Compared to the control culture, the percentage of primordial follicles was reduced (P < 0,05) and the percentage of developing follicles was increased ( P < 0,05) after 2 or 6 days of culture in all media tested. Furtherimore, culture of the ovarian cortex for 6 days reduced the percentage of healthy, morphologically normal follicles when compared with the control (P < 0,05). In contrast, cultures supplemented with 10 ng/ml of IAA were the only samples that had similar (P < 0,05) percentages relative to the control group. Finally, we found a mammalian gene that was homologous to the plant gene, ROOTY, which may be involved in the oocyte response to IAA. We conclude that the 10 ng/ml concentration of IAA promoted follicular survival and activation of nelore bovine preantral follicles after 6 days of culture in vitro.

Reproductive performance of ewes mated in the spring when given nutritional supplements to enhance energy levels

The objective of this study was to evaluate the reproductive performance of ewes mated in the spring when given nutritional supplements to enhance energy levels. Ewes were assessed for weight and body condition at the beginning and end of flushing periods. Lambing rates and rates of proliferation were also evaluated. Crossbred woolly ewes (n = 46), 36 ± 2 months of age and rated 3.0 ± 0.1 on a body condition scale that spanned from 1 to 5 were divided into four treatment groups. One group received no feed supplements (NFS), while the others were supplemented for 64 days: 21 days before and 43 days during the mating season. The latter groups were fed soybean hulls at 0.6% (S06), 0.9% (S09) and 1.2% (S12) of their body weight (BW), calculated using dry mass. Ewes were mated for 50 days with four rams by means of natural breeding in October and November, which is spring in Brazil. There was no significant difference among the treatments based on mean BW of the ewes before and after the supplementation period (P > 0.05). Similarly, no differences were found in the rates of proliferation (P > 0.05). The S09 treatment presented the highest lambing rate (82%, 9/11), while the NFS treatment correlated with the lowest rate (42%, 5/12; P < 0.05). There was a positive linear effect for body condition score as the supplementation level increased (P < 0.05). We conclude that a supplementation level of 0.9% BW seems to improve lambing rates for ewes that undergo springtime mating.(AU)

Reproductive performance of ewes mated in the spring when given nutritional supplements to enhance energy levels

The objective of this study was to evaluate the reproductive performance of ewes mated in the spring when given nutritional supplements to enhance energy levels. Ewes were assessed for weight and body condition at the beginning and end of flushing periods. Lambing rates and rates of proliferation were also evaluated. Crossbred woolly ewes (n = 46), 36 ± 2 months of age and rated 3.0 ± 0.1 on a body condition scale that spanned from 1 to 5 were divided into four treatment groups. One group received no feed supplements (NFS), while the others were supplemented for 64 days: 21 days before and 43 days during the mating season. The latter groups were fed soybean hulls at 0.6% (S06), 0.9% (S09) and 1.2% (S12) of their body weight (BW), calculated using dry mass. Ewes were mated for 50 days with four rams by means of natural breeding in October and November, which is spring in Brazil. There was no significant difference among the treatments based on mean BW of the ewes before and after the supplementation period (P > 0.05). Similarly, no differences were found in the rates of proliferation (P > 0.05). The S09 treatment presented the highest lambing rate (82%, 9/11), while the NFS treatment correlated with the lowest rate (42%, 5/12; P < 0.05). There was a positive linear effect for body condition score as the supplementation level increased (P < 0.05). We conclude that a supplementation level of 0.9% BW seems to improve lambing rates for ewes that undergo springtime mating.