Synchronisation of oestrus in sexually mature gilts can be achieved by suppressing the ovarian activity with progesterone analogues for the period longer than the lifespan of corpora lutea, according to S. Jacob of Ceva in Libourne, France and co-authors there and Scent Istvàn University in Hungary.

After the withdrawal of such inhibition, new follicular phase will start in all treated animals at the same time, resulting in synchronised onset of oestrus (Martinat-Botté 1989).

In numerous studies, the administration of altrenogest to the gilts resulted in the increased fertility rate compared to non-treated animals.

The objective of this study was to compare the efficacy of Altresyn® (Ceva) with another altrenogest product and the control, not synchronised gilts.

Material and Methods

Puberal gilts were allocated into three groups G1-G3 with 40 animals in each group. After the first observed heat G1 was treated with Altresyn for 18 days, G2 with product A for 18 days and G3 included gilts in their second spontaneous heat.

All gilts were inseminated twice with 12 hours interval after the standing heat was observed in the presence of the teaser boar. Four weeks after insemination, the gilts were tested for pregnancy by ultrasonography.

Results

All gilts came in heat after the treatment. The average interval between the end of treatment was six days in G1 and 6.5 days in G2. In the treated groups, three gilts were re-inseminated (one in the Altresyn group and two in the group G2), while four gilts were re-inseminated in the control group. There were no statistically significant differences among the groups (P>0.3589), however more gilts were re-inseminated in the control group than those in the treated groups.

In each treated groups, two gilts were not found pregnant while there were four non-pregnant gilts in the control group. There were no statistically significant differences among the three groups (P=0.6752), however more gilts were non-pregnant in the control group (two versus four).

	Oestrus rate	Non-returns	Pregnancy rate
Altresyn	100%	97.5%	95%
Product A	100%	95%	95%
Control	N/A	90%	90%

Conclusion

Treatment of gilts for 18 days with product A and Altresyn resulted in 100 per cent induction of oestrus within a predicted time interval.

The pregnancy rate was numerically increased in treated gilts in comparison to the controls, however the difference was not statistically significant.

Altresyn proved to be a highly efficient product when used for managing the oestrus in replacement gilts.

Bibliography

Martinat-Botté F.: Proc.JRP, 1989, 21; 125-58.