Figure 1.
Figure 1.

Map of Spain and Portugal with the approximate location of the 9 weather stations (identified with W) and the 16 farms (identified with F).

 


Figure 2.
Figure 2.

Number of observations for farrowing rate and total born in relation to maximum temperature for gilts (sows from parity 1) and sows (parity 2 to 7).

 


Figure 3.
Figure 3.

Means for farrowing rate and total born per °C maximum outside temperature for gilts (sows from parity 1) and sows (parity 2 to 7). An asterisk (*) indicates significance of difference between gilts and sows within each temperature class.

 


Figure 4.
Figure 4.

Pearson correlations between farrowing rate of gilts (sows from parity 1) and daily temperature variables. Farrowing rate was corrected for the systematic effects of herd, year of insemination, the interaction between herd and year of insemination and service sire. Day zero was the day of first insemination in a parity. Vertical bars in a) and b) show SE of the correlations. Heat load in c) was estimated as deviation from the upper critical temperature (UCT) considering 3 levels of UCT (i.e., 15°C, 19.2°C, and 25°C). A sixth degree polynomial function was fitted to the correlations.

 


Figure 5.
Figure 5.

Pearson correlations between farrowing rate of sows (parity 2 to 7) and daily temperature variables. Farrowing rate was corrected for the systematic effects of herd, year of insemination, the interaction between herd and year of insemination and service sire. Day zero was the day of first insemination in a parity. Vertical bars in a) and b) show SE of the correlations. Heat load in c) was estimated as deviation from the upper critical temperature (UCT) considering 3 levels of UCT (i.e., 15°C, 19.2°C, and 25°C). A third degree polynomial function was fitted to the correlations.

 


Figure 6.
Figure 6.

Pearson correlations between total born of gilts (sows from parity 1) and daily temperature variables. Total born was corrected for the systematic effects of herd, year of insemination, the interaction between herd and year of insemination and service sire. Day zero was the day of successful insemination in a cycle. Vertical bars in a) and b) show SE of the correlations. Heat load in c) was estimated as deviation from the upper critical temperature (UCT) considering 3 levels of UCT (i.e., 15°C, 21.7°C, and 25°C). A third degree polynomial function was fitted to the correlations.

 


Figure 7.
Figure 7.

Pearson correlations between total born of sows (parity 2 to 7) and daily temperature variables. Total born was corrected for the systematic effects of herd, year of insemination, the interaction between herd and year of insemination and service sire. Day zero was the day of successful insemination in a cycle. Vertical bars in a) and b) show SE of the correlations. Heat load in c) was estimated as deviation from the upper critical temperature (UCT) considering 3 levels of UCT (i.e., 15°C, 21.7°C, and 25°C). A third degree polynomial function was fitted to the correlations.

 


Figure 8.
Figure 8.

Means for farrowing rate (corrected for the systematic effects of parity, herd, year of insemination, the interaction between herd and year of insemination and service sire) in relation to maximum temperature on the 21st day before first insemination for daughters from sires grouped according to their sensitivity or robustness to high temperatures. The symbols show the corrected daughter averages for each temperature class and the lines show the estimated effect of maximum temperature on the 21st day before first insemination on farrowing rate for daughters from robust and sensitive sires.

 


Figure 9.
Figure 9.

Means for total born (corrected for the systematic effects of parity, herd, year of insemination, the interaction between herd and year of insemination and service sire) in relation to maximum temperature at day of successful insemination for daughters from sires grouped according to their sensitivity or robustness to high temperatures. The symbols show the corrected daughter averages for each temperature class and the lines show the estimated effect of maximum temperature at day of successful insemination on total born for daughters from robust and sensitive sires.