Inverted teats in gilts – effect on piglet growth rate

Helena Chalkias¹, Nils Lundeheim¹, Magdalena Jacobson²

¹Dept. of Animal Breeding and Genetics; ²Dept. of Clinical Sciences,

Swedish University of Agricultural Sciences, Uppsala, Sweden

Email address: Helena.Chalkias@slu.se 

The aim of this study was to evaluate the growth rate of piglets that have suckled previously inverted teats that have protruded before farrowing. The study is based on five Yorkshire gilts and one Yorkshire*Landrace gilt with 4, 4, 4, 5, 6 and 8 inverted teats, respectively,  as recorded at 100 kg live weight. The gilts where inseminated with Hampshire boars. Except for two gilts, all inverted teats had protruded at farrowing (one teat in each gilt, respectively, remained inverted). After farrowing, all excessive teats were blocked with bandage to ensure that each piglet only had access to one single teat. The piglets were weighed individually each day during the first week and thereafter once a week until weaning at 4 weeks of age. For each piglet, the type of teat was registered (protruded or normal). The two piglets that suckled the inverted teats, were not able to emerge the teats by stimulation and were euthanized 4 and 8 days after birth, respectively, due to loss of body weight (150 g and 80 g). Both these piglets were still fighting for other teats the day they were euthanized, but necropsy revealed empty intestines and sparse amount of feed in the stomach. Totally 72 piglets were born (70 live born and 2 stillborn) and when excluding piglets that died before weaning, as well as piglets that developed some kind of disease (especially lameness), 48 pigs remained for analysis (26 pigs nursed normal teats and 22 pigs nursed protruded teats).

The average live weight of the piglets at 28 days of age was 9.1 kg in the control group and 8.7 kg in the group with protruded teats. The weight and growth rate was analyzed using repeated observation mixed-model analysis of variance. Fixed effects included in the statistical model were sow, sex, teat type (normal/protruded), day after farrowing for weight and week after farrowing for growth rate and also the interactions day*teat type or week*teat type. Piglet was included as a random effect nested within teat type. There were no significant differences in weight/growth rate between the two groups, but numerically, piglets nursing protruded teats had lower weight gain.

It was unexpected that the majority of the inverted teats protruded several weeks or even month before farrowing. We can conclude that if teats remain inverted at farrowing they do not have any functional value.