The post-calving period is a time of major metabolic change for a cow, and ensuring her nutrition needs are met over the next few months is critical in hitting a 365-day calving interval.
Recent climate conditions have lead to great variability in spring weather. The stark fluctuations between warm and cold temperatures make the transition from indoor forage-based rations to outdoor grazing more difficult to plan and manage.
“The very dry weather combined with cold night temperatures for April really hampered grass growth and for many farmers, there was a deficit of grass at turnout.
“If, as a result, cows start to lose body condition in the lead-up to service there could be a marked impact on fertility,” says Dr Tim Potter, senior clinical director at Westpoint Farm Vets, part of the VetPartners group.
Below, Dr Potter shares his advice on the nutritional management of suckler cows in the run-up to, and during, the service period.
1. Prioritise at-risk cows
Certain cows are more likely to experience difficulty getting back in-calf, and these should be prioritised for potential management interventions.
At-risk cows include those that:
- Were over-fat or too thin at calving
- Had a difficult birth or caesarean section
- Experienced metabolic diseases such as hypocalcaemia
- Were affected by conditions such as retained cleansings and metritis.
Cows rearing twins should also be singled out because of the additional demand of growing two foetuses plus heightened requirements for milk production.
While isolated problems are always to be expected, if you have experienced reoccurring problems at calving, it would be worthwhile identifying the root cause now.
There could well be a simple solution and a change in management or routine could help overcome the problems for next year.
2. Monitor grass quality and availability
Nutrient intakes are typically easier to manage when cows are inside, with forage routinely analysed and suitable rations formulated accordingly.
Ensuring a smooth transition between winter forage rations and grazed grass is important to avoid a negative energy balance.
Test fresh grass quality and use a plate meter to monitor the level of grass available.
If there’s insufficient grass on the grazing platform then supplementary feeding should be considered to prevent a decline in body condition.
Ideally, cows should be at a body condition score of 2.5-3 and on a rising plane of nutrition at the point of service.
While supplementary feeding may not be required on a whole-herd basis, consideration should be given to at-risk cows, with the option to manage them separately.
The clock starts ticking as soon as the cow calves and if she fails to get back in-calf within the three-month window, this will extend the calving interval and reduce profitability.
3. Consider micronutrition
Poor micronutrient status can be common but varies widely between herds and often comes down to localised areas of grazing, with different soil types between regions and even between fields.
If you’ve had trouble with fertility and extended calving intervals in the past or noticed signs or symptoms that may indicate a deficiency, it’s worth investigating.
As the first port of call, you should find out what micronutrition is being provided in the grass or forage.
This can vary significantly and may highlight a specific trace element or vitamin shortfall.
Then, work with your vet to rule out other causes of disease, cows not returning to cyclicity, higher rates of infection during calving, or the production of weaker calves.
If there are no obvious causes, consider specific diagnostic tests, such as blood samples or liver biopsies, to test for trace element deficiencies.
Which micronutrients are important for fertility, and how should they be supplemented?
Tom Butler, group technical manager at Brinicombe, says that while they form a small part of cattle diets, micronutrients are crucial when it comes to fertility.
He says certain ones are key:
- Iodine is particularly important pre- and post-calving for hormone production, which is key to support fertility and early foetal growth. Iodine deficiency in pregnancy can lead to poor calf vigour at birth.
- Trace elements such as manganese, zinc, and copper also aid fertility as well as enhancing skeletal development.
- Other trace elements work with vitamins to improve breeding performance. For example, selenium helps support a healthy immune system and acts as an antioxidant in conjunction with vitamin E. Cobalt is essential for the production of milk and vitamin B12, as well as improving conception and growth rates.
- The inclusion of vitamin A within diets can also help boost conception rates.
- Vitamin D3 aids calcium and phosphorus absorption.
There are a variety of options when it comes to mineral supplementation, and the best option will depend somewhat on your system.
Cattle can be supplemented in many ways, including adding minerals within total mixed rations and offering free-access mineral licks. Boluses are a popular option due to their reliability and longevity in supply.
“While there’s the handling of the animal involved in administering the boluses, beyond that point no further labour is needed,” says Mr Butler. “And many farmers like to have peace of mind that trace element and vitamin requirements are taken care of for the duration of the grazing season.”
Dr Potter agrees that boluses are useful in delivering a controlled amount of nutrients to individual animals, similar to administering an injection.
“Bolusing can be built into management plans. With the micronutrients slowly released directly into the reticulum, you can be certain they are receiving the correct daily level,” he says.
“However, there are various boluses on the market which offer differing levels of micronutrients – speak to your vet about which is best for your herd.”