What are the consequences of heat stress in sows?

The domestic sow has non-seasonal reproductive cycles every 18-24 days (polyestrous) that are only interrupted by other physiological processes such as pregnancy and lactation, or due to other endocrine disorders. However, we can observe a tendency in breeding sows to show more irregular cycles during the summer months. It is called “seasonal infertility syndrome”, and it is caused by the effect of:

  • high temperatures
  • reduction of the photoperiod
  • physiological basis inherited from the boar

Due to this syndrome, we can observe a negative change on certain reproductive parameters, which are linked to:

  • lower feed intake
  • decrease in hormone production, due to the lower ovarian activity

These effects in reproduction can be:

  • Delayed puberty of gilts
  • Increase in the weaning-oestrus interval, so increase in the percentage of females in anoestrus
  • Decreased fertility and abortions
  • Increased acyclic repetitions due to embryonic losses
  • Decrease in prolificacy

Hence, the preventive measures we can take to lessen the impact of this reproductive seasonality are the following:

  • Photoperiod control throughout the year
  • Efficient ventilation and cooling
  • Optimized feed intake
  • Use of drinking water as a heat conductor
  • Treatment with exogenous hormones



Quiles, A., Hevia, M. 2007. Infertilidad estacional en la cerda. Producción animal., 233: 4-14.

Falceto, M.V.(2006 a). Prevención y tratamiento del anestro en la cerda: Anaporc. Volumen 3, Nº 27, Pp: 32-40.

Rodríguez-Estévez,V.;SánchezRodríguez, M.;Díaz Gaona,C.(2010). La infertilidad estacional porcina.El anestro y la infertilidad estacional de la cerda. Editorial Servet-Grupo Asis



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