Rearing heifers is a significant cost to dairy businesses with that investment often not recouped until their second lactation; and yet, on average, 17% of milking heifers exit the herd before this point.
A previous AHDB study found that only 24% of farms reached a profit during the first lactation. On most farms, the heifers weren’t repaying their cost of rearing until the second lactation. And in most cases, they were well past halfway through that lactation.Giving heifers the opportunity to calve down for a second time is therefore not only important for your bottom line but also for herd longevity, your carbon footprint and consumer perceptions.
Monitoring performance for successful transition
Monitoring performance of your milking heifers is key, as well as considering management changes that will help them adapt to herd life, finish growing and realise their genetic potential.Ideally heifers should calve at about 24 months, at around 80-85% of their mature body weight. It’s a busy time as they’ve still got plenty of growing still to do once they’ve entered the milking herd and they’re also expected to get back into calf.
The consequences of a poor transition at calving can be metabolic diseases such as ketosis and milk fever as well as other reproductive issues such as retained placenta or metritis. There is growing evidence that suggests inflammation is a key factor in the development of transition disorders as it can suppress the immune system and impede nutrient uptake.
The importance of good foot health
In-calf heifers need extra care as they continue to grow, particularly around their feet as there’s a substantial body of evidence that shows that lameness in cows starts young.The soft tissues of the sole inside the hoof, known as the fat pad, is not only thinnest in younger animals but particularly maiden and milking heifers. On top of this, it’s also thin around calving, which can increase her risk of sole bruising and ulcers.
A Canadian study showed that cows diagnosed with sole lesions spent more time standing during the transition period compared to those that didn’t develop any lesions.
AHDB’s Dr Jenny Gibbons, Senior Animal Health and Welfare Scientist said: “Interestingly, the study found that most of the extra standing was perching in their cubicles. When cows perch, they typically stand with their front two feet in the cubicle so that much of their weight is going down through to their hind hooves putting pressure on those sensitive tissues.”
Another AHDB funded study found that giving heifers anti-inflammatories at calving, as well as every time she became lame, reduced her risk of becoming lame in the future.
Managing heifer behavior and group dynamics
After calving, thinking about a heifer’s behaviour can help to minimise stresses on a cow’s feet. They have different social, feeding and lying behaviours, compared with older cows. They feed more slowly, ruminate less, are lower in the pecking order, can be easily chased away from feed space or lying areas and will often avoid cubicles previously used by dominant older cows.Consideration should be given to the impact of changing groups on fresh heifers. Is there more pushing and shoving, particularly at feed areas, water troughs or cubicles that’s putting extra pressure on her feet?
“Just spending a bit of time looking at how they move around the shed can be insightful. What is the cow flow like? Are there any dead ends in the shed where they could get cornered and standing for too long?” said Dr Gibbons.
Running a heifer only group for the first four months until they reach peak yield is one way to reduce bullying, competition for feed and minimise stress.
Introduce heifers into the milking cow group in the quieter afternoon period as there’s less competition at the feed face and gives her an opportunity to explore her new environment. Moving heifers in pairs or small groups can help them adapt to their new home.
“Anything you can do to give them a stress-free environment with more space and easier access to lying and feed areas will give them the best chance to continue to grow and get back into calf,” says Dr Gibbons.
Space allowance and its impact on milk yield
The importance of space for cows should not be underestimated. Another study funded by AHDB and conducted at University of Nottingham reported higher milk yields in heifers compared with the older cows when given more space.Researchers compared 9sq m of total space with 14sq m. The heifers with the higher space allowance yielded an average of 600 litres more per heifer over a 305-day lactation. They also lay down for an extra hour each day and spent 10 minutes longer feeding. Heifers were able to access feed and cubicles more easily with less interaction with older, more dominant cows.
Before calving, heifers should eat a close-up dry cow ration and ideally be housed separately from older dry cows. If this isn’t possible, move them to the dry cow pen at 60 days before calving to allow them time to adjust to competing with older cows.
After calving, it can be beneficial to continue to house first calvers separately from older cows to reduce pressure on feed space and monitor for any fresh cow disease. However, if fresh heifers need to be housed with mature cows, stocking density in a pen should be 90% or less based on feed space.
Improving fertility and health to ensure these heifers calve down for a second time is not only beneficial to farmer’s bottom lines, but also their carbon footprint and the industry’s drive to achieve net zero carbon by 2040.
Top tips for a smooth heifer transition
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