AUTUMN calving dairy and beef suckler herds are approaching a critical time period for nutritional requirements, says Dr Elizabeth Berry, Veterinary Director with Animax.
“Seventy-five per cent of foetal development and growth takes place during the last trimester, significantly increasing energy and mineral needs of the dam,” Dr Berry says.
During this dry period, dry matter intake should be approximately two per cent of the cow’s bodyweight to reach target body condition score (BCS) for calving and to provide adequate energy for foetal development. While this will vary between cows, aim for 80 per cent of cows within 3-3.5 BCS at the end of lactation.
“If a cow is either in too poor or too fat body condition this can affect health and performance post-calving. Problems due to ketosis, milk fever, metritis and mastitis can occur along with an impact on fertility.
“It is best to work with your vet and nutritionist for the energy and protein requirements of your herd to make sure the target BCS is met,” explains Dr Berry.
Ration mixing and availability of trace elements pre-calving is critical. Cows being fed high fibre forage prior to calving need to have ad lib access to ensure intakes are not restricted due to hierarchy in the herd and the extra space the growing calf takes.
According to Dr Berry, inadequate feed availability can then lead to lower intakes of energy and protein but also essential trace elements such as copper, cobalt, selenium and iodine.
“Iodine regulates metabolism and supports foetal development and growth. If deficient, calving can be delayed and slowed, calves can have poor vigour, and the risk of still-births increases.
“Selenium not only supports the immune system for the dam to mitigate infections like mastitis, but it also provides immunity for the calf against things like white muscle disease,” says Dr Berry.
“Cobalt helps manufacturer vitamin B12 and supports the production of red blood cells and energy metabolism.”
Supplementation for copper, which is essential for optimising growth rates and fertility, will depend on pasture conditions or other factors such as animal genetics.
Many antagonists to copper are present in soil and high intakes of soil can occur under many conditions – tight grazing, and wet or dry weather result in more soil contamination of the grass. The dry matter intake of the cow can contain up to 18 per cent soil as well, when grazing over the summer.
“Copper deficiency is linked to poor fertility and depressed immunity, which can come with some significant economic consequences,” explains Dr Berry.
“If left untreated, this can also lead to poor growth, anaemia, weight loss, and diarrhoea. However, copper toxicity can occur if over supplemented, so it is essential a need is identified.”
According to Dr Berry, supplementation for the essential trace elements should begin 6-8 weeks before calving.
One of the most effective ways to ensure that ruminants receive optimum supplementation is to give a slow release trace element bolus.
Once a bolus enters the animal’s rumen or reticulum, trace elements begin to release. Animax’s Tracesure boluses use a proven and unique leaching bolus technology that provides trace elements at a steady, continuous rate for up to six months.
“Animax’s unique slow release bolus technology ensures optimum levels are supplied for a prolonged period of time,” adds Dr Berry.
“Not only will this take care of the dam’s trace element requirements for herself and foetal development ahead of calving, but it will support her immunity and production during lactation.”
As a significant amount of calcium is used in colostrum and milk production, dairy cows are vulnerable to milk fever just before or after calving.
“Milk fever typically happens within one day of calving along with when a cow’s body is most stressed.
“The cow has to mobilise large amounts of calcium from her bones and also take in calcium from her diet more efficiently, along with reducing excretion of calcium from the kidneys – this is a lot to manage,” explains Dr Berry.
Generally, calcium supplementation is reduced during the dry period leading up to calving, particularly the last few weeks, to increase the efficiency of mobilising calcium at calving. After calving, cows with conditions which put this at risk, including two or more lactations, laminitis infections, poor BCS, or a history of milk fever, can be given calcium in a drench or bolus form.
“A high calcium supplement like Easycal can be given around or after calving to increase blood calcium for 12-15 hours. Repeat calcium can be given as needed with no restriction on timing as Easycal contains a no-irritant calcium source,” concludes Dr Berry.