Bull and Ram Breeding Soundness Examinations
A complete bull breeding soundness exam is quite possibly the most effective management tool that a producer can implement to increase pregnancy rates and produce more calves faster. A bull impaired fertility can cost breeders time, money, and in extreme cases an entire calf/lamb crop. The risk of this can be diminished with routine screening of all breeding bulls before the breeding season.
Decreased fertility or serving capacity of bull can lead to lower conception rates and pregnancy rates in affected flocks and herds. A complete breeding soundness exam 30-60 days prior to the breeding season can alert producers to problems with the male and prevent substantial pregnancy loss due to bull fertility problems.
Complete Breeding Soundness Exams include the following:
- Brief physical exam
- Scrotal circumference measurement
- Palpation of prostate, vesicular gland etc.
- Semen Collection
- Semen evaluation using phase contrast microscopy
What is Phase Contrast and why is it important?
Sperm cells (spermatozoa) are microscopic; they must be examined under a microscope. Regular light microscopes have some degree of light refraction which makes examination of membrane edges very difficult. The anatomy of the head of the spermatozoa (acrosome) and the appearance of the nuclear material within the head are very important in predicting the fertility of that bull. Using a phase contrast microscope one can clearly pick up most acrosomal and nuclear irregularities on spermatozoa. Unfortunately a regular light microscope which is used by most veterinarians, does a poor job picking up these defects. This is important to note. The acrosomal and nuclear material defects are highly correlated to fertility performance in the bull. Phase contrast will pull out about 8-10% of bulls for being unsatisfactory that would be called satisfactory using regular light microscopes.
|
