Influence of temperature stimulation during the last 6 days of incubation on hatching results and later performance in Pekin ducks

In three incubation trials and three growing trials the influence of temperature manipulation at the end of incubation on hatching results and performance in Pekin ducks was investigated for 49 days. A total of 1730 eggs (Pekin duck) were incubated from Days 1 to 22 under normal incubation conditions (37.6°C) and then sorted into two hatch incubators (37.0-37.2°C: control; 38.0-38.2°C, 2 hours daily: short-term warm stimulation - Trial 1; 36.0-36.2°C, 2 hours daily:short-term cold stimulation - Trial 2 and 3). In Trial 3, 1-day old ducklings were selected by sex. In Trial 2 and 3 duckling quality was analysed in a random sample using the Pasgar©score. In growth Trial 1 and 2, a total of 192 unsexed ducks from each incubator and in Trial 3, 36 male and 36 female ducks from each incubator, were used for a 49-d fattening period. The short-term warm stimulation reduced the percentage of hatched ducklings. The short-term cold stimulation did not change the hatching results. Further, under these incubation conditions the ratio of hatched female to male ducks shifted in favour of the female ducks. In the control group and the short-term cold stimulated group the Pasgar©score was between 9 and 10. In the first subsequent duck growth trial, the mean daily feed intake and weight gain for the short-term warm stimulated ducks was statistically lower than for the control group in the first three weeks. In Growing Trial 2 (without sex sorting) short-term cold stimulation had no influence on feed intake. But, in Growing Trial 3 (with sex sorting), it could be demonstrated that short-term cold stimulation had an opposing influence on feed intake in male and female ducks; in male ducks feed intake was decreased and in female ducks increased, especially in the first growing period (Day 1-21). Body weight gain in the same growing period and body weight on Day 21 were statistically significantly higher in the short-term cold stimulated group in Growing Trial 2. Similar results were obtained in Growing Trial 3, but the statistically significant increase in both parameters was exclusively found in female ducks. On the other hand, short-term cold stimulation improved feed to gain ratio during the whole growing period exclusively in male ducks. The male and the female ducks from short-term stimulated group reached statistically higher crude protein content in the breast meat compared to ducks of same sex from the control group at the end of the trial.