Epsilon Archive for Student Projects

Abstract

Knowledge in reproduction in the Swedish lynx (Lynx lynx) is important for
several reasons. Situated on top of the food chain, lynxes may be at risk of being
exposed to environmental toxins that could have adverse effect on reproduction.
The population of lynxes is today managed by restricted hunting which demands
knowledge about both the lynxes numbers and their reproduction. In addition,
lynxes may function as indicators of climate change for instance if their season of
heat would be earlier or prolonged due to a warmer climate. Today’s knowledge
in reproduction in Swedish lynx is mainly based on information gathered from
radio collared animals. The Swedish National Veterinary Institute (SVA) gather
reproduction organs from lynxes on regular basis, both from hunted animals and
from animals found dead. In earlier studies, the method of placental scar counting
has been used to estimate pregnancy rate and litter size. Lynxes differ from other
felids as their corpora lutea remains in their ovaries for a long time, maybe several
years. In earlier studies classification and counting of corpora lutea and Graafian
follicles has been done to estimate ovulation frequency. This work, which
includes reproductive tracts from 32 female lynxes, aimed to evaluate which
methods would be appropriate to use when evaluating reproductive tracts in
lynxes. In addition, basic data were gathered for continuing environmental
monitoring and assessment. When counting placental scars pregnancy rate was 72
percent. The number of placental scars ranged from 1-4 and were on average 2,24
+ - 0,70. This data accords with previous data on pregnancy rate and litter size of
the lynxes. Corpora lutea remains in the ovaries for more than a year making it
hard to properly count the corpora lutea due to difficulties to determine how old
they are. When determining stage of the oestrous cycle it is useful to consider
several parameters. Two lynxes had paraovarian ectopic adrenal tissue in the
ovarian ligament, to the author’s knowledge not previously described in the lynx.