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Fertility and metabolism of dairy cows carrying “fertil+” or “fertil-” haplotype for one QTL of female fertility located on the chromosome 3

The decrease of fertility in dairy cows is related, in part, to the intensity of selection on milk production. Studies performed by geneticists allowed the detection of several QTLs (Quantitative trait locus) of female fertility in dairy cow. We have studied fertility and some zootechnic parameters in dairy cows carrying “fertil+” or “fertil-” haplotype for one QTL of female fertility located on the chromosome 3 (QTL-Fert-BTA3).

Prim'Holstein cows grazing. © INRA, SLAGMULDER Christian
Updated on 11/13/2013
Published on 10/17/2013

Fertility and some zootechnic parameters have been studied in dairy cows carrying “fertil+” or “fertil-/-” haplotype for one QTL of female fertility located on the chromosome 3. The results showed a higher fertility (determined by the success of the first artificial insemination) that could be explained by a better oocyte quality and/or a better potential embryo development in “fertil+” animals. “Fertil+” dairy cows have also a better energy balance during the first week of lactation and a lower eating rate.

Context and challenge

In the last decade, the fertility of high producing dairy cows has been continuously damaged, especially in the Holstein breed. This decrease of fertility is related, in part, to the intensity of selection on milk production. Studies performed by geneticists allowed the detection of several QTLs (Quantitative trait locus) of female fertility in dairy cows. We have studied fertility and some zootechnic parameters in dairy cows carrying “fertil+” or “fertil-” haplotype for one QTL of female fertility located on the chromosome 3 (QTL-Fert-BTA3). This QTL is involved in the early pregnancy failures (Druet et al., 2007).

Results

Several parameters have been studied in 41 dairy cows (n = 18 "fertil-" and n = 23 "fertil +") during the first lactation. We observed that "fertil-" animals lost more weight than "fertil +" animals in the first 7 weeks after calving. In this same period, milk production and food intake of primiparous "fertil-" were lower than those observed in primiparous "fertil +". In addition, dairy cows "fertil +" have a slower eating rate (Coyral-castel et al., 2012a). Plasma progesterone profiles showed that "fertil +" animals resumed ovarian activity faster than "fertil-" animals after calving. Finally, we found a higher rate of success of the first artificial insemination in "fertil +" animals than in "fertil-" animals (Coyral-Castel et al., 2011). Since we noted no difference in the number of follicles and the number of follicular waves or cycle between "fertil +" and "fertil -" animals, we suggested a difference of oocyte or embryo quality between the two haplotypes. Analysis of oocytes recovered from preovulatory follicles after ovarian stimulation in heifers showed that oocyte maturation was retarded in "fertil-" than "fertil +" animals in vivo. This last result could reflect a lower potential embryo development in "fertil-" animals (Coyral-Castel et al. 2012). Furthermore, in dairy cows in third lactation (n = 8 per haplotype), the rate of oocyte maturation after in vitro maturation was significantly altered (early arrest or late meiotic maturation) in"fertil-" animals (Brisard et al. 2012). Genes involved in prostaglandin synthesis were lower expressed in cumulus cells surrounding in vivo mature oocytes in "fertil-" animals than in “fertil+”. In contrast, several genes of QTL-F-Fert-BTA3 were similarly expressed in both haplotypes.

Perspectives

To understand the molecular mechanisms involved in the early pregnancy failures in “fertil-” dairy cows and to study the role of some genes included in the QTL-Fert-BTA3 in the reproductive functions.

Publication/patent

-Brisard D, Desmarchais A., Touze JL, Coyral-Castel S., Nuttink F., Dupont J., Uzbekova S. 2012

Analyse de la maturation ovocytaire et de l’expression génique dans les cellules du cumulus chez des vaches laitières portant les haplotypes Fertil+ et Fertil- d’un QTL de fertilité situé sur le chromosome 3. 3R, 5-6 decembre 2012, Paris.

-Coyral-Castel S, Faverdin P, Rame C, Freret S, Guillaume D, Fritz S, Dupont J. 2012a. Significant differences in fertility between dairy cows selected for one QTL located on bovine chromosome 3 are not attributable to energy balance, although eating behaviour is affected. Animal:1-8.

-Coyral-Castel S, Brisard D, Touze JL, Dupont M, Rame C, Uzbekova S, Dupont J. 2012b. Analysis of in vivo oocyte maturation, in vitro embryo development and gene expression in cumulus cells of dairy cows and heifers selected for one fertility quantitative trait loci (QTL) located on BTA3. Theriogenology.

-Coyral-Castel S., Ramé C, Monniaux D, Fréret S, Fabre-Nys C, Fritz S, Monget P, Dupont F, Dupont J., 2011. Ovarian parameters and fertility of dairy cows selected for one QTL located on BTA3. Theriogenology, 75:1239-1250.