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The naked truth about mink births

Ground-breaking movie shots of mink births reveal that there is potential for producing more mink kits.

900 video hours of births is probably more than even the most gung-ho expectant father can live up to when recording the delivery of the little ones on film. However, that is what scientists at the Faculty of Agricultural Sciences at the University of Aarhus have done. In just one year – as the first in the world – they have recorded 900 hours of movies of mink births.

The movie shots are quite ground-breaking since the births usually take place inside the minks’ straw-packed nest boxes, where even the most curious of mink farmers has no access without disturbing the nest. The films show how the mink dam solicitously helps each kit into the world while at the same time keeping track of the other kits in the newborn litter.

The most surprising observations, however, are how many kits are born compared to the number that farmers usually count, and how long the delivery lasts for some of the dams. Now the researchers are expanding on their newly found wisdom and will investigate how more kits can be saved and how the protracted deliveries can be shortened.

Shorter deliveries – more live kits

The videos show that on average it takes a mink female nine hours to deliver her whole litter. The average number of kits at birth is 9.6. Already one day later this number is reduced to 7.0 live kits. That means there is great potential for producing more mink without having to increase the number of dams, if more knowledge can be gained about why mink kits die perinatally.

The film shots show that the duration of the delivery has a strong influence on how many mink kits survive. In dams that did not lose any of their kits, the delivery only lasted five hours. In dams that lost 88 percent of their liveborn kits, the delivery lasted twice as long, on average 10 hours. Therefore, there is every reason to investigate the factors that affect duration of the litter’s delivery. There is a great variation between mink dams and it looks like their possibility to build a nest as well as their condition has some bearing on this.

Fat dams have a greater risk of protracted delivery. Both thin and fat dams often have births that are irregular. That means births that start, stop, start and stop. It seems that the optimal case is a satisfactory condition at birth. But whether it is the dam’s condition itself or the way in which the condition was achieved, for example due to various levels of activity, remain to be seen. The scientists are at present investigating that.

For further information please contact senior scientist Jens Malmkvist, Department of Animal Health, Welfare and Nutrition, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 1314, e-mail: [email protected]

Wednesday 09 May 2007 | Communication Unit