Zu den Auswirkungen der Rangposition auf die Fruchtbarkeitsleistung von Sauen
Abstract. Title of the paper: Impact of rank position on fertility of sows
The investigations were carried out with 460 sows from two farms (farm A: housing the sows in small groups of 8 animals each, farm B with a large group of 100 sows) and a total number of 901 matings. The number of agonistic interactions was registered for each sow during 48 h after mixing soon after weaning the piglets. The individual rank place in the social hierarchy was calculated on the basis of wins and defeats and the sows were divided in high and low ranking sows. At farm B the rank position was estimated on the basis of the daily feeding order at two electronic feeding stations (first half = high ranking, second half of the sows in the feeding order = low ranking). Additionally, the following parameters were recorded for each sow: parity, farrowing rate and litter size (total and alive born piglets). The analysis showed that sows with a high rank position had a significantly higher farrowing rate (89.8 %) compared to pen-mates with low rank places (83.9 %, p<0.05)(farm A). Sows with a high rank position reached a significantly higher litter size of total born piglets (12.51, 16.14 piglets per litter respectively) than the low-ranking pen-mates (12.00, 14.83 piglets/litter respectively – farms A and B). In tendency the difference concerning the litter size between sows with high and low rank position was larger in sows with parity 2 than in sows with a higher parity number (farm A). When mixing sows, the time and the conditions (e.g. group size, space allowance per sow) have to be considered to prevent the negative influence of (low) rank order on fertility.