For 21 sows, teats were hand milked individually in a standard way during farrowing in an attempt to produce an index of teat quality. The piglets' teat selection and 14-day weights were then compared with the hand milking results. Of within-litter variation in 14-day weight, 38.67% was explained by 1-day weight, and only 4.6% extra variation by the index derived from hand milking. Use of the index gave no improvement over previous models involving 1-day weight and teat number (anterior to posterior). Hand milking showed a pronounced decline in colostrum yield from the most anterior teat pair (46.8 g) to the most posterior (13.7 g); this may help to explain the piglets' strong tendency to select anterior positions. Piglets of high, medium and low 1-day weight differed significantly in liveweight gain, but not in their selection of anterior or posterior teats.
Fraser, D., & Lin, C. S. (1984). An attempt to estimate teat quality of sows by hand milking during farrowing. Canadian Journal of Animal Science, 64(1), 165-170.