At any given time 10-15% of rams will fail to mate with ewes or mate and fail to get ewes pregnant, this can be caused by a variety of factors which can include:
- poor libido due to illness, old age or being immature
- physical injury or damageto penis, hernia, lame foot or sores on the brisket
- disease such as Brucella Ovis infection
- poor nutrition or sudden change in diet can cause nutritional stress or ‘melt’
- fever or heat stress through environmental conditions
- excessive body condition or malnutrition
- low testosterone levels
The critical temperature at which ram semen begins to die off is 40oC or 104oF, it is important to monitor ram temperature, in the 6 weeks prior to the breeding season. The temperature of the testicles does not have to be raised very much or for long, for significant damage to semen production and semen quality to occur.
The testicles need to be kept 4-5oC cooler than the ram’s core body temp as over-heating destroys semen producing cells in the testicles and the testicles may become soft and small. When a ram is identified as having a raised temperature of over 39.9oC, you should administer treatment as advised by your veterinary surgeon as soon as possible.