Dairy cow health and lifetime productivity can be optimised by taking a ‘marginal gains’ approach from birth, says Merial Animal Health’s Veterinary Advisor Sioned Timothy.
Small changes to herd management throughout a cow’s life can result in big improvements in health, fertility and productivity, thus reducing costs and making dairy herds more efficient.
Key phases in a cow’s productive life include birth and early life, heifer growth, transition to the milking herd, and lactation.
The opportunity to improve productivity starts at birth.
On many farms, calf mortality is highest during the first month of life with neonatal scour the most common disease during this period, accounting for almost 50% of all calf deaths.
Nutrition from birth 'a key factor'
“Good nutrition from birth is a key factor in ensuring heifers are healthy right through until their first calving.
"Optimising calf management at birth can help reduce the likelihood of scouring,” says Ms Timothy.
“Adequate intake of good quality colostrum is vital, ideally within the first 2 to 4 hours of life.
"Where there is concern about the quality of colostrum, or the level of challenge on the farm is known to be high, products such as Locatim®, a lactoserum which is administered to calves soon after birth and contains specific antibodies against E.coli F5 (K99), can help to boost protection against disease.”
Bovine Respiratory Disease (BRD) is common in dairy calves and growing cattle, particularly during the housing period.
Calves which have a compromised immune system, through lack of maternally derived immunity, stress or malnourishment, are more likely to become infected with the bacteria and viruses that cause disease.
Impact of BRD
The impact of BRD is wide reaching and calf pneumonia accounts for almost 40% of deaths at one to four months of age.
Pneumonia infection can result in 66g reduction in daily growth in the first month of life alone3 and infections can impact on a lifetime of productivity with reduced milk yield in adulthood.
Taking steps to prevent BRD is always cheaper than treating outbreaks.
Calves should be housed in adequately ventilated buildings without draughts, and stocking density should be appropriate to the age of calves and the space available.
Avoid mixing calves of different ages and immediately quarantine any unwell animals to reduce cross-infection.
Temperature monitoring tools and careful observation of calves can help identify infections at an early stage, which can help reduce the severity of pneumonia.
Vaccination is also important in preventing BRD infections.
Bovalto® Respi 3 and Respi 4 vaccines provide calves with protection against common causes of BRD, including respiratory syncytial virus (RSV), parainfluenza-3-virus (PI3), bovine viral diarrhoea virus (BVDV) and bovine herpes virus 1 (BHV-1) and Mannheimia haemolytica.
Heifer rearing
Heifer rearing is the next key phase in a cow’s life where improvements can be made to lifetime productivity.
“The wide ranging benefits of optimised heifer rearing systems are now well recognised,” suggests Ms Timothy.
“Efficient heifer rearing can support herd expansion without the need to buy in replacements and can also increase the rate of genetic improvement.
“In order to achieve a 24 month average age at calving heifers must reach approximately 60% of mature weight by 14 months of age."
"This requires an average daily weight gain of at least 0.7-0.8kg during the period between weaning and bulling."
"However, it’s more important that growing cattle meet breed-appropriate target weights since the onset of puberty and breeding is more closely linked to cow weight, body size and condition score than age.”
'Poor parasite control'
Losses in potential liveweight gain due to poor parasite control during a heifer’s first grazing season will not be recouped during the second year at grass.
Affected animals will not catch up, and this will impact on their ability to meet important growth milestones, which could result in an increased age at first calving.
The impact of parasite challenge as heifers approach reproductive age is supported by studies showing increased mammary development and earlier onset of puberty in strategically wormed heifers in comparison to those left untreated.
“Effective worming with anthelmintics such as Ivomec® Classic (ivermectin) can mitigate the effect of parasites on growth and fertility levels in growing cattle, while still allowing them to build the necessary immunity required to prevent clinical disease in adulthood,” advises Ms Timothy.
This focus on growth must be maintained during pregnancy since a continued steady weight gain is required if heifers are to calve at 90% of mature weight, and transition well into lactation.
The weeks following calving present the next opportunity to optimise productivity, by minimising the effect of the energy gap.
Reduced body condition scores may impact on reproduction, increasing the time it takes to get cows back into calf.
The focus should be on maximising dry matter intake to correct the energy imbalance as quickly as possible.
Improved appetites
Studies have shown that cows treated for gutworm have improved appetites, and graze for up to an hour longer than untreated cows.
Parasite challenge during this period may also impact on fertility; heifers treated for gutworm around the time they calve down have been shown to have a 20% higher conception rate at first service than untreated cattle8.
“Dairy farmers should look at employing a range of practical measures throughout the transition period to ensure cows are as productive and efficient as possible,” says Ms Timothy.
“In addition to the recognised impact of gutworm on milk production, parasite burdens have a broader effect on productivity so targeted worming with a zero milk withhold wormer such at Eprinex® (eprinomectin) should be considered at this critical time.
The marginal gains approach can help improve the overall productivity and profitability of each individual cow and the herd as a whole.
It requires dairy farmers to focus on every phase in a cow’s life to improve calf health, heifer growth and fertility, efficient transition and optimised lactation.
This can be achieved through herd health plans and by continual assessment of cow health. Dairy farmers should ask their vet or animal health adviser for more information.
