Butorphanol tartrate acts to decrease sow activity, which could lead to reduced pig crushing

The objective of this study was to determine whether administration of an a nalgesic to sows immediately after farrowing would allow them to Lie more r estfully. Sows lying on their pigs, causing them to be "crushed," is a majo r cause of pig mortality. Most deaths due to crushing occur during the firs t 3 d postpartum. For modern, lean-type sows, farrowing crates are relative ly hard and unforgiving, even though they may be equipped with plastic-coat ed, expanded metal flooring. Indeed, many sows develop pressure sores on th eir shoulders, and this may contribute to the sows' discomfort. These sores may cause a sow to change position frequently to alleviate pain, thus incr easing its chances of crushing pigs. Sixteen production sows were assigned to either a control group (C, n = 8) with litter size 11.71 +/- .78 or an e xperimental group (B, n = 8) with litter size 11.63 +/- 1.22. Pigs born to C and B sows weighed 1.60 +/- .04 and 1.37 +/- .04 kg, respectively. The C sows were given no treatment, whereas the B sows were administered an i.m. injection of butorphanol tartrate at a dose of .15 mg/kg BW every 6 h until 3 d after farrowing. Data were collected on all sows using time-lapse phot ography (1 frame/.4 s) for a 3-d duration upon the initiation of farrowing. To assess the degree of comfort of each sow, body position changes were re corded when sows switched between lying, sitting, and standing. Data were a nalyzed by 12-h periods using Wilcoxon-Mann-Whitney equations. During the 7 2-h period, B sows tended to perform fewer position changes than C sows (P = .10). Specifically, position changes were fewer for B sows from 48 to 72 h postpartum (P < .06). There were no differences in position changes betwe en treatments from 0 to 48 h postpartum (P > .50). There was no difference in the rate of crushing between treatments (C = 5, B = 5). The butorphanol did not seem to affect pig activity or normal behaviors or to create advers e effects, such as diarrhea. Although the sows given butorphanol showed a r educed number of position changes, the dose was intermediate, and a higher dose may have a greater effect. If pig mortality can be decreased, an analg esic protocol that is simple to administer and readily available to produce rs can be developed. Alternatively, using of more pliable flooring or an in crease in sow body fat may allow sows to lie more stationary.