South Africa

Health Care

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Preparing Bulls for the Breeding Season Part 1

(This is article 1 of 2 articles on this topic)

Bulls do not always get the necessary attention in preparation for the breeding season. The importance of the genetic contribution to the herd, the costs associated in the buying of quality bulls, and the necessity to optimize reproduction, forces us to attend to the well being and preparation of bulls to be performance ready!

The following areas should get the necessary attention:

1.  Body Condition Score (BCS)

The body condition of the bull leading up to and during the breeding season, is just as important as that of the cow. During the breeding season, bulls' grazing time is limited and they spend a lot of energy which drain their reserves. If the bull's condition is not optimal at the start of the breeding season, it will adversely affect his ability to work, as well as their fertility - especially with a 3 month breeding season. (Figure 1)

Figure 1. Bull too lean to start

It is therefore important to evaluate the condition of the bulls at least 8 weeks before the start of the breeding season and make adjustments in their nutrition if necessary. A condition score of 3 (out of 5), that builds up to at least 3.5 to 4 at the start of the breeding season is desired. (Figure 2)

Figure 2. Optimal condition

Beware of giving bulls too much high-energy concentrate in the run-up to the breeding season. This can lead to the accumulation of fat at the neck of the scrotum, which is detrimental to fertility.

New bulls should preferably not be bought less than 60 days before the start breeding season. Bulls bought at auctions are usually in a very good condition (4+). (Figure 3) These bulls' supplementation must be gradually reduced over a period of at least 4-6 weeks to a BCS of not more than 4. If bulls lose condition too quickly, they can become weak and infertile during the breeding season. If the bulls are joined in an “auction” condition, they will most likely "fall apart" as they go from a concentrate based diet (in preparing them for the auction), to a roughage based diet(veldt / crop residues) on the farm.

 

 

                                             

 

Figure 3. Over conditioned 

NB. Consult with a nutritionist on the best options for the specific circumstances.

2.  Breeding soundness

There is much more to “breeding soundness” than just being “fertile”. Breeding soundness includes:

2.1 Anatomy - the following must be inspected/evaluated:

  • sheath - must not be too long and/or damaged (Figure 4)
  • penis - must be able to come out fully and not be broken/crooked
  • scrotum - must be symmetrical, not too long (testicles hanging too low) and must not be split at the base (Figure 5)
  • testicles - must have a solid consistency, be equal in size and not twisted, be without lumps/injuries and large enough for the age of the bull
  • hooves - must not be grown out and/or cracked
  • joints - must not be stiff/injured to prevent bull from jumping a cow


       Scrotal circumference 1

Figure 5. Scrotum circumference


Figure 4. Good sheath & scrotum

2.2 Libido - the bull should be “interested” in the cows

2.3 Diseases - bulls should be tested on a regular basis and be free of (venereal) diseases like trichomoniasis and vibriosis. Newly bought bulls should be tested to be BVD PI negative.

spermmicro.jpg2.4 Semen quality and quantity. The evaluation of semen should include the following analysis / measurements:

  • Macroscopically - color, density, movement, volume
  • Microscopically - semen morphology (head / tail abnormalities), presence of foreign cells (pus cells)

     

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