Performance and behavior of dairy heifers according to their milk dietÉdith Charbonneau, Doris Pellerin, Marc-André Sirard, Débora Santschi, Elsa Vasseur
- Raising an excessive number of heifers has a direct impact on the expenses and costs associated with premature culling.
- At a cost of $3,207 per heifer, a reduction in the cow replacement rate from 33.9% (average rate in Quebec) to 30% for a herd of 60 cows would result in a decrease in the company’s expenses of more than $15,000 per year, merely in relation to heifer rearing costs.
- When heifers are selected, genetics is often the only criterion used even though it is now known that many other factors can influence a heifer’s future productivity, including immunity transfer, lacto-replacer consumption and average daily weight gain.
- Using a tape measure to record thoracic circumference is the tool that is most frequently used on farms to assess weight. However, correlations with this measurement and weight have not been validated for animals weighing more than 100 kg. It would be beneficial to verify if this tool also works for younger animals.
- The milk feeding phase can affect growth and production.
- Epigenetics also offers an interesting explanation of gene regulation and a way to determine the factors influencing weight gain and future milk production.
The objectives of this project are:
- to evaluate the effect of different milk feeding management scenarios on weight gain (preweaning performances), productivity (postweaning performances) and gene methylation (epigenetics);
- to evaluate the different milk feeding management scenarios on calf behavior;
- to validate the use of a tape measure to assess the weight of very young heifers.
Results and potential benefits
To attain these objectives, one experiment involving more than 300 heifers is currently underway on two dairy farms implementing a milk feeding phase with an automated calf feeder. The experiment has two different milk feeding management scenarios (restricted vs. unrestricted) as treatments. Data collection until weaning is complete. Data have been collected three times per week for the first three weeks of life, and then every two weeks until the calves are weaned. To date, more than 300 calves have been recruited for the project and more than 5,000 data entries on weight and height have been recorded. The experiment continues on one farm to obtain the impacts of treatments on postweaning performances. Thus, the heifers will also be weighed and measured before their first insemination and in the days preceding calving. Milk production will also be recorded during the first three months of lactation on the farm. In addition, a sub-sample from the first experiment will be used for epigenetic analysis. Data on milk supply programs (restricted versus unrestricted) will provide recommendations to farmers. There is currently a lack of guidelines for the feeding of young heifers in Quebec.
- Marwa Hasnaoui, master’s student, tape measure validation
- Ousmane Magassa, master’s student, calf behaviour
- Another master’s student will be recruited, Relationship between the milk feeding phase, preweaning performances and gene expression
- Another master’s student will be recruited, Relationship between the milk feeding phase on postweaning performances of heifers
Special call for proposals in dairy production and processing (2016–2021)
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Quebec consortium for industrial bioprocess research and innovation (CRIBIQ)
- Fermes Algério and Ferme M. G. L’Heureux