Breeding EDGE key takeaways
The MLA Breeding EDGE workshop is a content-packed three-day workshop hosted by knowledgeable industry professionals. There are several key takeaways from the workshop which can be used by producers to increase their knowledge in herd reproduction and boost herd performance and profits.
1. Take a measure of your current herd performance
It’s important to know how your herd is currently performing in terms of reproductive ability.
The first step includes setting clear aims and objectives for your herd. Think about what you want to see in your herd in the next 5, 10 or 15 years. Some of your objectives could be:
- Example: increase fertility in the herd with improved conception rates by 10%
- Example: improve weaning rates by 5%.
It’s important to establish a baseline of conception rates to see where improvements can be made and identify where losses may be occurring. Using an experienced pregnancy tester will help provide information on where to improve your herd. Taking accurate records of pregnancy and weaning rates will provide a foundation and if used correctly can help make decisions on selection and retention of females to improve desirable traits.
2. Breeder herd management and plan
There are several things producers can focus on in their breeder herd to improve production.
Nutrition and supplementation:
Good breeder nutrition is key to a high performing herd. Adequate nutrition provides the best chance for breeders to cycle, conceive, raise a calf and resume cycling in as short amount of time as possible. Breeders require a minimum body condition score 3 at calving for lactational requirements. This requires keeping paddocks to recommended carrying capacity and frequently reviewing your forage budget. Nutrition also includes supplementation where required, such as phosphorous when grazing in deficient areas.
First calf heifers have lower reproduction rates in comparison to seasoned breeders. Heifers in particular need to be supported to ensure they cycle and reach critical mating weight (CMW) prior to joining. After weaning, heifers should be segregated into paddocks separate from the main breeding herd and supplemented accordingly. It’s important to monitor pastures and supplementation to ensure heifers grow to their full potential and reach puberty as early as possible. Segregation should continue until their first calf is weaned for retention or culled based on early life heritable or undesirable traits. If this is not possible, other ways of identifying them can be employed.
Age and weight at puberty
Age and weight at puberty is breed specific and highly heritable traits. Average Brahman weight at puberty, known as critical mating weight (CMW), was found to be 340kg. It’s important heifers be at their CMW at joining to achieve pregnancy. If nutrition and supplementation requirements are good and there are no other issues, genetic improvements can be made on selecting heifers who conceived earliest in the joining period.
Post-partum anoestrus interval
The period between calving and conceiving is known as the post-partum anoestrous interval (PPAI). PPAI is genetic and can be a factor for low conception rates when all other factors such as disease or nutrition are sound. First calf heifers require monitoring when rejoining to ensure heifers are selected based on low PPAIs.
Joining and calving date
Producers should aim for breeders to conceive and calve at certain times of the year to maintain body condition in the dry season. For controlled mating, the joining date should occur one month after the green date – otherwise known as the beginning of the growing season. In a controlled mating herd, bulls should be joined over 4 months with conception to occur within months (P4M). The aim is to calve down approximately 6 weeks before the green date so peak lactation requirements coincide with peak pasture production point.
In continuously mated herds, a good heifer management program is recommended to start the breeders’ calving at the right time when lactational requirements coincide with the feed production peak. Continuous mating herds can employ foetal aging pregnancy diagnosis to cull or segregate and manage cows calving out of season to limit poor nutritional consequences.
Time of weaning is important for preserving breeder body condition and improving future reproductive performance. Weaning can also reduce grazing pressure as it reduces the nutritional requirements of the breeder. For continuous mating herds it’s recommended two rounds of mustering and earlier weaning is employed to reduce the adverse effects of lactational requirements when breeders calve in the dry season. Ideally, the breeder should already be pregnant when the calf is weaned.
3. Bull management
A fertile bull will impregnate 60-70% of 50 females in the first cycle and 90% of females across three cycles.
Bull fertility is based on:
- Soundness (structural)
- Reproductive soundness
- Semen quality
- Libido and serving quality.
When buying bulls, potential bulls should be assessed against herd objectives using Estimated Breeding Values (EBVs) as well as other selection tools. Bull performance and soundness should be assessed by using BULLCHECK for soundness evaluations and sperm morphology. A BULLCHECK examination will assess bulls on their:
- Scrotum: sheath, scrotum including circumference and testicles
- Physical: overall structure free from defects including legs, feet, eyes, mouth/teeth
- Semen: quality and quantity
- Serving and libido.
Bulls with good libido will cover more cows thereby reducing the need for more bulls. Bulls purchased for libido using BULLCHECK can reduce the bull percentage required from 4% to 2.5%.
Annual re-examinations and pre-joining checks should be carried out to ensure bulls are in good reproduction health prior to mating.
The examinations should include:
- Structural soundness: testicle and scrotum palpation, examination of the penis, prepuce and sheath; palpation of internal sex organs; semen testing for quantity and quality (per cent normal sperm).
- Bull to cow joining ratio should be assessed.
- Nutrition: aim for 3-4 body condition score.
- Dominance effects: keep bulls of similar ages and libidos in the same mating group to ensure body condition is maintained and fighting reduced.
4. Reproductive disease management
The most common diseases that affect herd fertility are pestivirus, vibriosis and trichomoniasis. These diseases act by increasing the bodies temperature and effecting spermatogenesis (production or development of sperm). These diseases can have no signs or symptoms in the carrier bulls yet can have a great effect on reproduction rates.
A biosecurity plan is an important part of managing diseases.
Bull disease management
When joining bulls, mate young, unexposed bulls to heifers or first calf cows to reduce the likelihood of infection to diseases.
- Vaccinate for vibriosis, leptospirosis, botulism and three-day sickness
- Tick fever vaccination for bulls travelling from no-tick to tick areas
- Annual vaccination for leptospirosis, three day and vibriosis
- Young bulls should be vaccinated with 7in1 at branding, then again 4 ̶ 6 weeks later
- New bulls vaccinated for vibriosis with two injections given 6 ̶ 8 weeks apart, thereafter an annual booster given 4 weeks prior to joining.
Care should be taken when introducing new bulls to ensure persistently infected (PI) bulls are not introduced to a herd. Request this information from the vendor – an ear notch test can be taken to ensure they are not PI.
Female disease management
- Maiden heifers: vaccinate prior to joining:
- Vibriosis: make sure bulls are vaccinated before joining. If high risk to vibriosis, vaccinate twice, 4-6 weeks apart
- Leptospirosis: if possible, give booster shot prior to joining or vaccinate when pregnancy testing
- Pestivirus: a high rate of previously exposed animals in the herd means vaccination for pestivirus is unwarranted.
- Cows: annual boosters
- Vibriosis (only in high-risk areas)
- Leptospirosis – vaccinate at pregnancy testing
- Pestivirus – annual shot at pregnancy diagnosis. A whole herd vaccination program will mean continuing vaccination is recommended.
5. Genetic improvement and selection
Selecting bulls to buy and heifers or cows to retain should be based off several tools.
When selecting bulls, use a combination of estimated breeding values (EBVs) and BULLCHECK to determine the suitability of a bull to your breeding objectives. Some bull EBVs have a correlation to the daughter’s reproduction traits. To improve genetic traits, select bulls based on:
- Above breed average ‘Days to Calving’ EBVs which reduces the PPAI
- Scrotal circumference is moderately correlated with age at puberty. Selecting a bull for above average scrotal circumference can reduce their daughters’ age at puberty.
- Per cent normal sperm (PNS) is correlated with days to calving.
In a breeding herd, genetic improvements can be made through heifer selection and culling with the following tactics:
- Over-mate and retain heifers who got into calf earliest in the joining period.
- Retain those heifers who reached puberty earliest.
- Retain first calf heifers who got into calf again in the next joining period while lactating.
- Cull heifers when CMW cannot be reached by two years of age even in good nutrition. PPAI and weight at puberty are heritable so culling can improve reproductive traits.
This article is a summary of the MLA Breeding EGDE course. If you want to learn more about improving your herds reproduction rates, find a course near you.