BullManagementL6

• Calving Heifers


  Process of birthing young female cattle
• Why's Bull Breeding Soundness Exam (BSE) important?

  Critical to obtain optimum reproduction in beef cow herd and maintain a concentrated calving pattern, predicts potential fertility of a bull
• What does BSE involve?


  History/health status of herd of origin of bull or existing herd, PE, semen collection/exam, libido or serving assessment
• What does a physical evaluation of bulls involve?

  Palpation of scrotum and testes, vet evaluates testicular tone which relates to testicular function, look for deviations (hard, soft, inflamed) can affect consistency/size resulting in abnormal sperm production
• What is the relationship between scrotal circumference and sperm production in bulls?

  Scrotal circumference and testicular size are directly related to sperm production in bulls. As scrotal circumference increases, motility and percent normal sperm increase, and sperm abnormalities decrease.
• How can you measure scrotal circumference in bulls?

  Pull both testicles down into the scrotum and measure it with a tape.
• What factors affect the size of a bull's testicles?

  The size of a bull's testicles varies by breed and age of the bull
• What's highly correlated to testicular weight which is related to sperm producing capacity?

  Scrotal circumference
• How many cows can a bull with larger testicles mate with?

  Bulls with larger testicles can mate with up to 60 cows
• What is the minimum scrotal circumference recommended for bulls?

  Around 32-34 cm
• At what scrotal circumference do most British breed cattle reach puberty?

  Around 30 cm
• What is the relationship between scrotal circumference and female fertility?

  SC has a high positive genetic correlation to age of puberty of the bull's daughters, meaning that there is a relationship between SC and female fertility. Additionally, SC is highly heritable.
• Is there any relationship between libido, sexual activity, and semen production in bulls?

  No relationship
• How can the serving capacity of bulls be estimated?

  Via serving capacity tests
• What do serving capacity tests count for?

  Number of serves a bull performs in a set time with restrained females
• What is the Blockey test used for?

  Number of services that a bull achieves during the first three weeks of natural mating in the paddock
• Do all bulls have the same serving capacity?

  No, some bulls complete as few as 0-5 services while others serve 150, 200 or 250 times in three weeks
• How does high serving capacity of bulls affect the chances of pregnancy in cows?

  Bulls can detect cows in heat more efficiently, serve cows more than once, increasing the chances of pregnancy
• What is the yard serving capacity test used for?

  To count the number services a bull completes on a restrained cow in a 20-minute test and to detect unsound bulls and low servers (0 or 1 serve) who when mated to 40 cows get less than 40% pregnant in the first three weeks of mating
• How accurate is the yard serving capacity test in predicting a bull's paddock mating serving capacity?

  90% accurate
• What is the serving capability test?

  A simpler test that only gives a bull a couple of test serves
• Yearling bulls aren't easy to test
• Is there any ranking in serving capability tests?

  No, but the capability is proven
• Serving capability test less stressful on animals
• What are the benefits of serving capability tests?

  Detects arthritis and joint problems, particularly with older bulls
• Why do some bulls fail BSEs?

  Detects arthritis and joint problems, particularly with older bulls
• Why do some bulls fail BSEs?

  Immaturity, poor condition/heath status, lameness, penile damage, inadequate testicular size
• What are some selection criteria for bulls in breeding programs?

  Body condition: need energy reserves without being over-fat

  Feet, legs, joints, need to be excellent

  Pelvic measurements are a high heritability measure, but are generally found to be a poor predictor of calving difficulty.
• What are some of the challenges faced by a bull when it comes home?

  When a bull comes home, it faces several challenges such as adjusting to new yards and surroundings, a long journey, loss of mates, and the need to get vaccinated.
• Why is temperament important when dealing with a bull?

  Can be unpredictable and dangerous if it becomes agitated or aggressive
• What should you give a bull once it comes home?

  Recommended to give it a mate such as a steer or an old cow
• What should you avoid when placing a bull in a mob?

  A mob with older bulls, as this can lead to aggression and fighting
• Why should you consider giving a bull access to hay?

  May be used to good quality feed and hay, providing it with hay can help it adjust to its new environment and maintain its health and condition
• What should you note about rising 2-year-old bulls?

  Many rising 2-year-old bulls sold have not cut their second teeth, can be stressful causing them to lose condition when they do cut their second teeth
• What is the normal ratio of bulls to cows?

  Often 3% (3 per 100 cows)Some use 1 bull to 40 cows
• What is the ratio of young bulls to cows?

  Only have a ratio of 1/30 or less
• What factors determine the ratios of bulls to cows?

  Environmental conditions such as paddock size and terrain
• What is the ratio of heifers to bulls?

  Heifers have a lower ratio of 1:30
• Why do some people increase the cow-to-bull ratio?

  Decrease bull costs
• How many cows can a bull easily impregnate in a 60-day mating period?

  60 cows in a 60-day mating period