Expression of adipokine and lipid metabolism genes in adipose tissue of dairy cows differing in a female fertility quantitative trait locus.

We have previously characterized 2 haplotypes (Fertil+ and Fertil-) of Holstein dairy cows differing in 1 female fertility quantitative trait locus (QTL) located on chromosome 3 (QTL-Fert-F-BTA3) between positions 9.8 and 13.5 cM. This QTL is composed of 124 genes, some of them being involved in metabolism or reproduction. Primiparous Fertil+ and Fertil- cows exhibited 69 and 39% pregnancy rate at first service, respectively. A difference in plasma nonesterified fatty acid concentrations observed between both haplotypes might indicate a difference in adipose tissue mobilization. We compared adipose tissue gene expression in Fertil+ and Fertil- cows during their second lactation, at 2 physiological stages, implying either intense lipid mobilization (1 wk postpartum) or fat storage (5 mo of gestation). We investigated by reverse-transcription quantitative PCR the mRNA gene expression of 5 positional candidate genes located in the QTL-Fert-F-BTA3, as well as 18 other functional candidate genes encoding proteins involved in lipid metabolism and several adipokines. Among them, genes involved in either lipolysis or lipogenesis were chosen as controls because they were previously described in dairy cow adipose tissue. A hierarchical clustering was performed to group genes according to their expression pattern, allowing 2 clusters to be determined. Cluster 1 was composed of genes that were overexpressed during mobilization (ADIPOQ, ADIPOR2, LIPE, FABP4, PLIN1, RARRES, LEPR, and CPT1A) and cluster 2 of genes overexpressed during reconstitution of body reserves (ACACA, FASN, and SCD). Genes belonging to cluster 1 (LIPE, FABP4, PLIN1, and CPT1A) are known to be involved in lipolysis and fatty acid oxidation, and genes belonging to cluster 2 (ACACA, FASN, and SCD) are known to be involved in fatty acid synthesis. The expression of 5 genes from cluster 1 was correlated to plasma nonesterified fatty acid levels and thus to mobilization of body reserves in dairy cows (ADIPOQ, ADIPOR2, LIPE, PLIN1, and FABP4). During the mobilization stage, none of the positional candidate genes belonging to QTL-Fert-F-BTA3 (ADAR, MTX1, SHC1, SPTA1, and PAQR6) showed a difference in expression between the 2 haplotypes. Interestingly, ADIPOQ and ADIPOR2 were the only genes showing a significant mRNA overexpression in Fertil- cows at the mobilization stage. Further studies focusing on plasma adiponectin level and adipokine actions on the ovary are needed to investigate its potential role in dairy cow fertility.

Morphometry and depth of inseminating catheter penetration in prolific and non- prolific ewes at different ages: A post mortem study.

The ewe's cervix structure is highly variable among females, which may limit the application of transcervical artificial insemination (TCAI). This work aimed to study the variation in cervix anatomy in two different prolificacy breeds (D'man a prolific and Boujaâd a non-prolific sheep). Reproductive tracts were collected from D'man (n = 64) and Boujaâd (n = 187) females aged between 1 and 4 years. The weight of the uterus, length of the cervix and depth of penetration of the inseminating pipette were recorded. The number of cervical rings was counted and their arrangement graded. The cervix anatomy of D'man ewes differs from that of Boujaâd. The cervix morphology of Boujaâd ewes is more complex compared to D'man ewes; this complexity depends on the age of the ewe. No significant difference was found regarding the depth of penetration of the insemination catheter for the two breeds at 1, 2 and 4 years old (P > 0.05). However, at 3 years old, the highest depth of penetration (P < 0.05) was recorded in D'man ewes. In addition, for both breeds, grade 2 was the most frequent (P < 0.05), and the cervix became less complicated for TCAI with advanced age (4 years old). To conclude, the cervix of D'man ewes is less complex and more favorable to TCAI. In addition, to overcome the complexity of the cervix in Boujaâd sheep, a selection of 4-year-old ewes will make the penetration of the artificial insemination catheter possible.

Influence of heparin or the presence of cumulus cells during fertilization on the in vitro production of goat embryos.

Considerable research has been focused on in vitro production (IVP) of goat embryos to improve its efficiency. In Experiment 1, the effect of the cumulus cells by comparing slaughterhouse-oocytes denuded on purpose (DOP) prior to IVF to intact COC, and the effect of heparin during IVF were assessed. In Experiment 2, oocytes that were already denuded at collection (DOC), DOP and intact COC were studied. Three treatments used oocytes denuded at collection: DOC oocytes were cultured alone for both IVM and IVF; DOC and COC were cultured together for both IVM and IVF or DOC were IVM alone and then mixed with COC for IVF. In other treatments, COC were allocated to four IVF treatments: Intact COC; COC were denuded prior to IVF; COC were denuded and IVF with added cumulus cells; COC were denuded and IVF mixed with intact COC giving two sub-treatments: Denuded oocytes that were IVF with COC; and COC that were IVF with denuded oocytes. After fertilization, all presumptive zygotes were cultured for 8 days. In Experiment 1, the yield of blastocysts as a proportion of total oocytes was greater (P<0.05) for COC that were IVF in the presence of heparin (54%) than without heparin (42%) or oocytes already denuded at collection that were IVF with or without heparin (41%; 38%; respectively). In Experiment 2, the developmental potential of oocytes denuded at collection was reduced (cleavage and blastocyst rates calculated from total oocytes: 34%; 11%, respectively) as compared to COC (77%; 59%, P<0.05). However, when equal numbers of both were mixed at the start of IVM, the rates were not significantly different to COC alone (68%; 45%), but when both were mixed equally only for IVF, the rates were reduced (57%; 40%, P<0.05). Denuded oocytes co-cultured with cumulus cells were not significantly different to intact COC (76%; 55%). The effect of adding COC during IVF to oocytes denuded after IVM was similar to adding cumulus cells to the same type of oocytes. In conclusion, both the use of heparin and the association of oocytes with cumulus cells, either detached or in intimate contact, during IVM and/or IVF significantly improve IVP of goat embryos. Furthermore, some oocytes that are already denuded at collection will develop satisfactorily to blastocysts when matured and fertilized with intact COC.

Reproductive cycle of goats.

Goats are spontaneously ovulating, polyoestrous animals. Oestrous cycles in goats are reviewed in this paper with a view to clarifying interactions between cyclical changes in tissues, hormones and behaviour. Reproduction in goats is described as seasonal; the onset and length of the breeding season is dependent on various factors such as latitude, climate, breed, physiological stage, presence of the male, breeding system and specifically photoperiod. In temperate regions, reproduction in goats is described as seasonal with breeding period in the fall and winter and important differences in seasonality between breeds and locations. In tropical regions, goats are considered continuous breeders; however, restricted food availability often causes prolonged anoestrous and anovulatory periods and reduced fertility and prolificacy. Different strategies of breeding management have been developed to meet the supply needs and expectations of consumers, since both meat and milk industries are subjected to growing demands for year-round production. Hormonal treatments, to synchronize oestrus and ovulation in combination with artificial insemination (AI) or natural mating, allow out-of-season breeding and the grouping of the kidding period. Photoperiodic treatments coupled with buck effect now allow hormone-free synchronization of ovulation but fertility results after AI are still behind those of hormonal treatments. The latter techniques are still under study and will help meeting the emerging social demand of reducing the use of hormones for the management of breeding systems.