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Heifers entering their first breeding season require additional management. Although they should already be cycling before breeding, young females are often less reproductively active after winter than mature cows.
Breeding is one of the most important management aspects in a mixed farming enterprise and should never be left to chance. To assist producers in this regard, Stockfarm spoke with Dr Bastiaan Fouché of Parys Animal Hospital and Dr Paul Reynolds of Vrede Animal Hospital to compile a practical breeding season checklist.
According to Dr Fouché, a well-planned checklist helps maximise the benefits of every breeding season. Most cattle producers make use of two breeding seasons each year: one in summer from November to January, and the other in winter from May to August. The winter season often serves as a supplementary breeding period. Because cows are polyoestrous, they are not seasonally dependent and can come into heat (oestrus) throughout the year. A breeding season can therefore occur at any time, depending on management and economic considerations.
Cash flow and a second opportunity for females to conceive are important, he notes. For example, if 80% of cows conceive during the summer breeding season, the remaining 20% can be moved to the winter breeding season. The two- to three-month interval also allows sufficient time for pregnancy diagnosis and timely management decisions.
Select strictly for fertility
Dr Fouché explains that a standard breeding season in a beef cattle herd typically lasts from 42 to 63 days. However, the period must be shorter for heifers and form part of the checklist of every breeding season. A shorter period allows for deliberate selection for fertility. A 42-day breeding season gives heifers only two oestrus cycles in which to conceive, based on an average cycle length of 21 days. Those that conceive within this period have demonstrated superior fertility and good breeding values.
Once these heifers join the cow herd, the breeding season is extended to 63 days, covering three oestrus cycles of 21 days each. Dr Fouché explains that cows, particularly after calving, may occasionally skip a cycle. The longer breeding period therefore provides them with a better chance of returning to oestrus and conceiving.
The correct bull-to-cow ratio
The bull-to-cow ratio is one of the most important items on any breeding checklist. Dr Fouché recommends one bull for every 25 to 33 females, depending on the bulls’ age, condition, and fertility. Enough bulls must be available to ensure optimal mating. Use at least three bulls in a herd of 100 cows, although four are preferable.
Every bull should undergo a breeding soundness evaluation before the mating season. Dr Fouché’s golden rule is to place only bulls with a good body condition score and that have passed a fertility test with females. Bulls should also be screened for reproductive diseases before joining the herd. Trichomoniasis and vibriosis are two important diseases that infected bulls can spread, resulting in reproductive issues and abortions. Sheath scraping can be used to test for both diseases.
Nutrition and camp management
Dr Reynolds explains that nutrition and camp management are closely linked when preparing for the breeding season. The goal is for females to reach and maintain an optimal body condition score. “In the Eastern Free State, silage, greenfeed and spare camps with sufficient roughage are used as flush feed before the breeding season to improve body condition,” he says.
These camps can also serve as calving camps. Cows that maintain good condition during calving are more likely to reconceive within the desired breeding period. An effective lick programme forms part of the same management strategy. Every breeding checklist should therefore provide for flush feed and appropriate production licks. Dr Reynolds notes that animals whose body condition improves through flushing are more likely to come into oestrus than animals that lose condition or fail to improve. Feed sources will vary according to regional conditions and available resources.
Give heifers special attention
Heifers entering their first breeding season require additional management. Although they should already be cycling before breeding, young females are often less reproductively active after winter than mature cows. “A mature cow has already proven that she is reproductively functional,” says Dr Reynolds. “With heifers, producers must ensure that management does not compromise reproductive performance.”
To successfully select for fertility, heifers and first calvers should be managed separately from the main breeding herd. Dr Reynolds recommends grouping two- to four-year-old animals, including first calvers, together. Placing them in separate kraals reduces competition at feed and lick troughs, allowing younger, subordinate animals better access to nutrition. This helps them maintain body condition, improve reproductive performance, and conceive successfully.
| Conception (%) | |||
| Condition score | 130 cows | 340 cows | 2 000 cows |
| 1,5 | 0 | 0 | 0 |
| 2 | 25 | 38 | 50 |
| 2,5 | 50 | 49 | 75 |
| 3 | 74 | 73 | 88 |
| 3,5 | 91 | 88 | 95 |
| 4 | – | 100 | – |
Vaccination and supplementation
Dr Fouché emphasises effective control of abortion-causing diseases, such as brucellosis, to minimise reproductive losses. This will help ensure a high conception rate and calving percentage. Brucellosis testing should form part of every breeding season checklist, especially in herds experiencing poor conception rates. Dr Reynolds agrees and adds that vaccination is an essential component of reproductive management.
Read more: Manage bull and cow health in the breeding season
Heifers bred for the first time should receive the appropriate live vaccines. Vaccination delivers an excellent return on investment by protecting animals and improving reproductive percentages. Important diseases to vaccinate against, especially in young heifers, are enzootic abortion, bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR) and brucellosis, for which the RB51 vaccine is commonly used.
In older cows that have already calved, inactivated vaccines are generally administered for these diseases where live vaccines do not already form part of the herd health programme. The RB51 vaccine is usually avoided in older cows unless there is an issue on the farm. If the farm is clean and the animals have already been vaccinated, only the enzootic abortion (chlamydia) vaccine and the IBR/BVD combination vaccine are administered.
IBR and BVD are often associated only with respiratory disease, yet both are major contributors to reproductive issues and abortions. Where vibriosis or trichomoniasis has previously occurred, vaccination of cows and heifers may also be considered in consultation with a veterinarian. The trichomoniasis vaccine is not yet fully registered and must be specially ordered, while bulls can be vaccinated with Vibrin in selected herd health programmes.
Mineral supplementation is another essential component of reproductive management. Minerals play a supportive role during stressful periods such as calving, winter, and weaning. According to Dr Reynolds, research has shown that sufficient mineral supplementation not only reduces the effects of stress but also improves the animals’ response to vaccination.
He also highlights the important distinction between vaccination and immunisation. Vaccination refers to administering a vaccine, whereas immunisation is the successful development of protective immunity. Effective immunisation can only occur when animals are in good nutritional and physiological condition. A well-planned health and mineral supplementation programme is therefore essential for a successful breeding season. – Christal-Lize Muller, Stockfarm
For more information, contact Dr Bastiaan Fouché at 072 110 8273 or vet@parys.co.za or Dr Paul Reynolds at 082 587 7607 or beeste.paul@gmail.com
