How are we studying dairy cow longevity at CowLife McGill?

This blog post was written by Gabriel M. Dallago

Maximizing the length of time cows remain productive in the herd is essential to achieve a sustainable dairy industry. For that reason, cow longevity is one of the major components of the Industrial Research Chair in Sustainable Life of Dairy Cattle. This is the focus of my research as a Ph.D. Candidate and there is so much news that I would like to share with you.

Keeping cows longer in the herd and, consequently, increasing longevity has been pointed out as a problem in the industry. However, this statement becomes even more intriguing when we see that the longevity status is not always consistently reported by Dairy Herd Improvement (DHI) agencies or national databases. The first step in my research was to develop a standard methodology to estimate longevity in order to get a picture, at the country level, on the longevity status of dairy cows and to also be able to fairly compare countries.

Figure 1. Literature review presented at the IECA 2020 conference on cow longevity.

By using yearly official statistical publications from high milk-producing countries, we were able to estimate the longevity metric called the length of productive life, which measures the length of time between first calving and culling/death. In doing so, we found that dairy cow longevity in fact decreased in most countries evaluated, confirming the concerns raised by the industry. We were happy to have these results presented as a literature review at the 1st International Electronic Conference on Animals (Figure 1). What made us even happier was that after the conference, we were also invited to submit our work for publication in the Special Issue for IECA 2020 in the Journal Animals. You can check out the Open Access full paper by clicking on Figure 2 below.

Figure 2. Invited literature review published in the IECA Special Issue of the Journal Animals.

Once we confirmed that longevity had decreased, we started looking for early life conditions that might be associated with the length of time a dairy cow remains in the herd. We started by evaluating offspring birth conditions (i.e., birth ease, birth size, and twinning) routinely collected on Quebec dairy herds by Lactanet, the Canadian DHI agency. The results of this study showed the long-term effect of early life events on offspring, providing new insights on early life selection of the best candidates for replacement. We could not keep these results to ourselves! So, we were happy to present them at the 44th edition of the Symposium Sur Les Bovins Laitiers (Figure 3).

Figure 3. The study presented at the 44th edition of the Symposium Sur Les Bovins Laitiers.

The news does not stop there (!!), but this time we switched gears a little bit. Moving from early life to adult life, we conducted a study to profile the welfare status of Quebec dairy herds based on welfare indicators measured in lactating cows, and to evaluate its relationship with not only longevity, but also productivity and profitability. We found 5 unique welfare profiles and the profile with the best overall welfare status also had the highest longevity, productivity, and profitability. If you are interested in hearing more about this study (and also a 3-min presentation of my PhD Thesis), I will be presenting it at the Forum Techno 2021 between June 8th and 10th. The online event is organized by Novalait and this time it will be a joint event with the IDF International Cheese Science and Technology Symposium. Registrations are open!

Conferencing will continue over the summer with a couple of presentations to the scientific community at ADSA and in the fall I will be busy wrapping up my thesis (!!). More to come!