Observations on the Modified Serving Capacity Test for beef bulls

Area of Science:

• Veterinary Science
• Animal Reproduction
• Beef Cattle Production

Background:

• Breeding soundness evaluations are crucial for maintaining beef herd productivity.
• Traditional physical examinations may not identify all causes of reduced male fertility.
• The Modified Serving Capacity Test (M.S.C.T.) was developed to assess bull reproductive fitness.

Purpose of the Study:

• To evaluate the efficacy of the M.S.C.T. in diagnosing breeding unsoundness in beef bulls.
• To identify common causes of reproductive failure in bulls.
• To assess the impact of M.S.C.T. on improving herd fertility rates.

Main Methods:

• Physical examinations were conducted on 466 beef bulls between 1979-83.
• Blockley's Modified Serving Capacity Test (M.S.C.T.) was employed to assess serving ability.
• Breeding records from two beef herds utilizing the M.S.C.T. were analyzed.

Main Results:

• Seventy-eight out of 466 bulls (16.7%) were diagnosed as unsound for breeding.
• The M.S.C.T. detected 64 of the 78 unsound bulls (82% detection rate).
• Common issues included penile deviation (33), low libido (14), intromission failure (11), and locomotor abnormalities (6).
• Two beef herds using M.S.C.T. showed a 4-5% increase in in-calf rates.

Conclusions:

• The M.S.C.T. is a valuable tool for identifying breeding unsoundness in beef bulls.
• Implementing M.S.C.T. can lead to significant improvements in herd reproductive efficiency.
• Consideration of animal welfare aspects is important in the application of M.S.C.T.