A genomic selection tool that is helping New Zealand sheep farmers lift animal performance is getting a revamp.
Sue McCoard says she and her fellow researchers, in partnership with the industry, are researching different feeds and feeding management options and their impact on whole-of-life performance.
This work will help to contribute evidence-based knowledge to support best-practice feeding systems that will enable farmers and calf rearers to make decisions on options that best fit with their farming system and target outcomes. And it includes cost-benefit evaluation of early life interventions on lifetime performance.
She says it’s important to understand how feeds and feeding management affect animal performance pre- and post-weaning in dairy and dairy-beef animals. A young calf undergoes much physiological development early in life. It is important to meet the nutritional requirements of young calves during this period, especially in artificial rearing systems.
McCoard says it can be a challenge with artificial rearing systems to replicate what a cow does well in caring for its offspring. They are trying to develop approaches that improve the growth, health and welfare of calves through improved nutrition. The research includes understanding how different feeds (e.g. colostrum, milk, solid feeds) and feeding management approaches (e.g. early weaning) affect animal physiology including development and function of the digestive tract and microbiome, mammary gland and the immune system. The implications of early growth and development on lifetime performance of beef and dairy animals are also being evaluated.
“The knowledge generated from this research will contribute to strategies which optimise how calves are reared, and quantify the benefits of investing in the early phase of a calf’s life in terms of profitability, health and lifelong productivity. This can be challenging in artificial systems because of the pressures put on the rearers as a result of the cost of feed and labour and the number of calves born each day in seasonal systems.
“It is important for us to be thinking about different rearing systems and tools to optimise calf performance. Then that thinking can lead to useful information for farmers which provides evidence of the potential benefits of the investment in calf rearing practices.”
It is important to think long term when calf rearing, and to consider the future use of the animal, e.g. replacement heifer or beef production.
She says a large proportion of calves born on a dairy farm are used for beef production, therefore understanding how early-life nutrition impacts on time to slaughter, meat yield and quality (e.g. tenderness and marbling) are as important as improving performance of dairy heifer replacements.
McCoard says they have found that feeding good quality colostrum over the first two days is important the rest of the calf’s life.
“This is the first milk out of the gland -- otherwise known as ‘gold colostrum’. We already knew health benefits of feeding gold colostrum but what we have found is that there are additional benefits of feeding the gold colostrum. It doesn’t just improve immune function of the animal; it also improves the development of the gut, reduces scours (and thus health interventions) and improves growth rate of that calf in the first five weeks of age.”
The team’s research, focused on the calf rearing phase, has also highlighted that feeding greater volumes of milk accelerates pre-weaning growth and improves gut and mammary gland development. Also, despite the current dogma, their research has shown that though feeding large milk volumes with no concentrates restricts rumen development pre-weaning, it does not negatively affect the weaning transition or post-weaning growth rates.
McCoard says the role of science is not to find the best calf rearing system, but to come up with evidence-based options that help an individual farmer make decisions about what will suit their specific farming system or business goals.
“Coming up with the knowledge that farmers can use to inform their decisionmaking on farm.”
Investment not a cost
A key message to calf rearers, says Sue McCoard, is to get lots of information about how the calves have been managed in the first four days of life on the dairy farm -- particularly whether they have been fed ‘gold colostrum’.
She says even paying a premium for calves that have been treated well and fed gold colostrum could be important for a four-day-old calf they are buying.
She says in rearing systems there are many different options.
“What we are trying to understand is how different feeds and feeding management affect the performance of calves in a pasture based farming system once they have been weaned, and how to improve lifetime performance through early life interventions.
“This work not only focuses on colostrum, milk and solid feeds (e.g. meal and pasture), but also potential novel feed additives and how to promote beneficial gut microbes that contribute to nutrition and health in calves, and rumen function in mature animals. There was a time when the bobby-calf was seen as a by-product of the dairy industry, effectively surplus to requirements. But because of the current value of beef there is growing focus on options to use more calves for beef production and this will require a quality product.”
McCoard says while genetics are important, feeds and feeding management of calves can impact lifetime performance. Their work with Hereford Friesian-cross heifers has shown that feeding large milk volumes, plus early access to good quality pasture over the first summer and autumn, can accelerate growth and reduce time to slaughter (sold before their second winter) despite restricted early rumen development.
The benefit of feeding good quality forage to calves over their first summer and autumn, irrespective of the pre-weaning rearing system, is also highlighted.
While the extra investment in milk feeding is not more profitable from a financial perspective for beef production at current milk prices, this system provides additional benefits. Accelerating growth rates through improved feeding in the first six months of life can substantially increase the number of cattle sold before their second winter.
Other benefits include reduced exposure during droughts and feed deficits by getting animals off the farm earlier, reducing overall feed demand, potential to reduce pasture damage and requirements for winter cropping.