Drinker to Nursery Pig Ratio: Preference for a Drinker Location within a Pen and its Effects on Aggression

The objectives of this study were to (1) calculate aggressive interactions around the water bowl drinkers and to (2) determine preference for a water bowl location when pigs were offered either one, two or three water bowl drinkers per pen. Information is available on the current drinker to nursery pig’s ratios (drinker: pigs). In the UK producers are recommended 1:15, while in the US it is 1:10 for nursery pigs. A total of 225 crossbred were seven weeks of age. Conventional nursery pens had plastic flooring and all pigs had ad-libitum access to a commercially formulated diet. Water was delivered through a single stainless steel water bowl drinker and was provided ad libitum. All pigs received a natural light cycle from a curtain sided building. Nine pens were used for behavioral measures. Three treatments were compared. Treatment one (TRT 1; n = 3) was defined as one water bowl drinker per pen. Treatment two (TRT 2; n = 3) was defined as two water bowl drinkers per pen. Treatment three (TRT 3; n = 3) was defined as three water bowl drinkers per pen. One day prior to visual recording of drinking behavior, all pigs in a pen were identified with an individual number. One 12 V black and white CCTV camera was positioned over each water bowl drinker and behavior was recorded from 0700 to 1300 h over two consecutive days onto a DVR at 1 frame per second. The acquisition of drinking behavior (defined as the pig having its head in the water bowl drinker for 5 s or longer) was obtained by three experienced observers who viewed the recordings using 24 h mode (5 frame / s) onto the Observer software. Total number of aggressive interactions and length of aggression around the water bowl drinker over the 6 h period was not (P \u3c 0.05) different between the treatments. The total amount of time that nursery pigs spent when offered two (F vs. O) water bowl drinkers in a pen did not (P = 0.47) differ. However, when pigs were offered three (F vs. O vs. A) water bowl drinkers in a pen there was a difference (P \u3c 0.0001) for total amount of time spent at all three locations. In conclusion, pigs displayed a water bowl drinker preference with the alley location being the least favored; however, there were no difference in the number or length of aggressive interactions