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Towards ”perfect” heifer management (summary)
The International Symposium on Dairy Cattle Nutrition 2019 (17 January) was happy to host almost 300 international participants for an exchange on the theme “Nutrition and health from dairy calf to heifer”. The symposium was organized by Wageningen University & Research and Utrecht University, in cooperation with Bayer Animal Health, Diamond V, and Zinpro. Eight well-known international speakers presented their vision on various aspects of heifer rearing.
Rearing costs underestimated
Starting with the economics of efficient heifer rearing, first speaker was Michel de Haan of Wageningen Livestock Research. Rearing replacement heifers contributes for about 17% to the total farm costs, with approximately €8.30 per 100 kg of milk. This is much more than expected by farmers: 74% underestimates the costs for heifer rearing. Being able to reduce the replacement rate improves resource efficiency as well as farm economics significantly, with or without the limitations of a phosphate ceiling as in The Netherlands.
Impact of prenatal circumstances
The next speakers continued on aspects of calf nutrition, starting with Prof. Geert Opsomer from Ghent University (Belgium), discussing effects of intrauterine circumstances on future performance. A strong negative energy balance of the cow or other stressors such as heat stress may influence placental development, birth weight, growth and insulin sensitivity. The prenatal circumstances may even influence future performance as a dairy cow.
Collostrum more than immunoglobulins
Prof. Michael Steele of the University of Guelph (Canada) continued with colostrum feeding of the new-born calf. The concept of colostrum feeding may need rethinking: there is more to colostrum than just immunoglobulins, such as oligosaccharides, that will affect gut development. After colostrum feeding, ad libitum milk feeding will support growth - if combined with an adequate gradual weaning strategy.
Energy improves protein metabolism
Prof. Walter Gerrits from Wageningen University finished the morning session with his work on protein metabolism in the growing calf. Protein efficiency of milk-fed calves decreases quickly with age and body weight. Increasing energy intake improves protein efficiency but the effect of amino acid supplementation is limited, which may be due to amino acid metabolism in the gastrointestinal tract.
Abrupt versus gradual weaning
After the lunch break Dr. Christian Koch from Hofgut Neumühle (Germany) continued discussing experiments with intensified feeding strategies and optimal timing of weaning. Weaning too early, with an underdeveloped rumen, may result in fermentation disturbances and health disorders. Ad libitum feeding until 8 weeks increases growth but gradual weaning is important and may last until 14-16 weeks of age.
Sick calves are not normality
Dr. Sam Barringer of Diamond V (USA) discussed the risk of normalization of deviance. Disease incidence, abnormal behaviour or reduced hygiene should never be considered ‘normal’. With some personal anecdotes he stimulated the audience to always ask themselves ‘why’. Understanding a farmer’s motivation is essential for your advice and ideas to land.
Group housing stimulates development
Dr. João Costa from the University of Kentucky (USA) gave his vision on calf behaviour and the importance of group housing for socialization and future performance. Group housing increases learning behaviour as well as feed intake and these effects may be lasting until adulthood. Group housing should be combined with accelerated milk feeding to reduce cross-suckling and prevent competition at the feeder.
620 kgs in 670 days
Dr. Àlex Bach from ICREA (Spain) was the final speaker showing how to raise a perfect heifer – in biological as well as economical perspective. To get there, we should address rearing goals in days instead of months, and aim at a perfect heifer calving at 670 days having at least 620 kg live weight. Reduced growth in an early phase needs to be compensated in later life; therefore it is important to consider the whole rearing period when evaluating heifer management.