TDK conference 2011

The number and the performance of mammary glands (glandulae mammaria) in breeding sows is an important maternal trait. Sows usually have five to nine teats (mamillae) on each side.

Results of relevant research confirmed that piglets realize only 50 or a little over 50 percent of their genetically determined growth potential in spite of the significantly increased milk yield.

1985 randomly selected sows (0.9 percent of domestic breeding sows) were included in the study, all of them within 48 hours after farrowing. Some animals were examined personally; information regarding the others was derived from questionnaires. The study is related to a previous survey performed at the slaughterhouse1,2.

The total number of mammary glands per sow were as follows: 16 mammary glands: 139 sows (7%); 15 mammary glands: 156 sows (7.9 %); 14 mammary glands: 1470 sows (74%); 13 mammary glands: 87 sows (4.4%); 12 mammary glands: 118 sows (5.9%); 10 mammary glands: 15 sows (0.8%). The average number of mammary glands per sow in the study: 14.03; the average number of properly functioning mammary glands: 13,07.

The number of mammary glands being non functional or not functioning properly per sow was 0.96. Following are the main categories of the latter group expressed in numbers and in percentages of the total number of mammary glands: inverted teat: 183 (0.7%); „blind” teat: 217 (0.8%); short teat: 380 (1.4%); mammary gland aplasia: 124 (0.5%); mammary gland hypoplasia: 354 (1.3%); non functioning mammary gland due to trauma or other reasons: 330 (1.2%).

Other anatomical abnormalities: accessory or supernumerary mammary glands: 60 sows (0.2%); supernumerary teats: 95 sows (0.3%). Positional abnormality, asymmetry: 69 sows (0.3%); not adequate space between the mammary glands: 94 sows (0.3%)

It raises ethical, animal welfare, animal health and economical issues if the piglets do not have access to properly functioning mammary glands in sufficient numbers. The technical and breeding selection aspects of increasing the number of properly functioning mammary glands are elaborated. The results of the present study underline the importance of increasing the number of functional mammary glands as well as improving their function.

(1) Kertész Attila Mihály: Numerical anatomical characterization of mammary gland and teat canal of domestic breeding pigs. SzIE, Faculty of Veterinary Science, Students' Research Circle, 2009.
(2) Kertész, A.M., Bíró, H., Sótonyi, P.: The number of mammary glands and teat canals in culled breeding sows. In: Proceedings of 1st European Symposium on Porcine Health Management, Copenhagen, Denmark, August 27th - 28th, 2009. p. 56.