Cow longevity

HOW COW LONGEVITY AND WELFARE IMPROVE HERD MANAGEMENT OVER THE LONG RUN

By Gabriel M. Dallago, Elsa Vasseur, Valérie Bélanger and Shelley Crabtree CONTRIBUTORS

Animal welfare is an important part of herd management, but what does the industry know about the relationships between welfare, herd performance and economics? Using Quebec data, researchers identified five herd profiles with various levels of welfare—from poor to good. The profile with the best overall welfare status also had the highest longevity, profitability and productivity.

Dairy cow longevity is a key aspect of achieving a sustainable dairy industry. As a result, longevity is one of the major components of the Industrial Research Chair in Sustainable Life of Dairy Cattle and research conducted by Gabriel M. Dallago, PhD candidate at McGill University.

The longer the cows remain productive in a herd, the more profitable the herd will be since cows only become profitable after the third lactation. This is when revenue from milk sales breaks even with all the costs associated with the rearing period (Pellerin et al., 2014). Mature cows in their third lactation or greater also produce more milk, resulting in more revenue compared with younger animals (Dallago et al., 2021). In addition, when cows are culled earlier than expected, it is often because of health and welfare issues. Therefore, improving cow longevity means improving cow welfare and vice versa.

Established by Novalait and its partners at McGill University in Quebec, the Industrial Research Chair in Sustainable Life of Dairy Cattle is headed by researcher Elsa Vasseur. The research team focuses on cow longevity in relation to cow profitability and welfare. Chair partners include Dairy Farmers of Canada, Lactanet and the Natural Sciences and Engineering Research Council of Canada.

CURRENT LONGEVITY STATUS

Increasing dairy cow longevity has been identified as a problem in the industry. However, longevity status is not always consistently reported by dairy herd improvement agencies or national databases. As a result, researchers focused on developing a standard methodology to estimate longevity in different countries to allow them to analyze the status and trends over time and make a fair comparison between countries.

The longevity metric length of productive life, which measures the length of time between first calving and culling or death, was estimated using yearly official statistical publications from high milk-producing countries (Figure 1). New Zealand was the only country where longevity increased. Meanwhile, no change was observed in the United States, Germany and the Netherlands, and longevity decreased in the remaining six countries, including Canada.

Once scientific evidence confirmed dairy cow longevity has decreased, the focus of the analysis shifted toward early life conditions potentially associated with longevity. Identifying those early life conditions could help improve the current situation by providing guidance on how to increase longevity.

Figure 1: Linear trend of longevity, measured by the length of productive life (year), in 10 high milk-producing countries as estimated using statistical models

EARLY LIFE INDICATORS OF LONGEVITY

Early life has been neglected when studying dairy cow longevity. The rearing period represents 40 per cent of a cow’s life, assuming the rearing period is two years and the productive life is three years, which are both the current average in Canada. Most research on cow longevity overlooks the rearing period and instead, focuses only on cows that have already calved for the first time.

As a result, the research team evaluated the effect of birth ease, birth size and twinning on female Holstein cows’ longevity in Quebec dairy herds. Researchers found small size at birth, complications during birth and occurrence of twinning greatly increased the chances of an animal being culled earlier once she reached the productive life stage. This was one of the first scientific studies that showed the long-term effect of such early life conditions on female offspring, providing new insights for early selection of replacement candidates.

Continued on page 34

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Figure 2: Five unique herd welfare profiles (clusters) of Quebec dairy herds based on welfare outcome measures collected on 2,696 farms between 2016 and 2019 *Welfare description and associations with performance and profitability of each profile is shown in the boxes. *The number of farms in each profile are shown between parentheses. *HSI = Herd status index, a composite index, which combines DHI indicators covering aspects, such as longevity, nutrition, profitability and reproduction, to conduct a remote assessment of herd welfare status.

How does cow longevity, profitability, welfare complement one another?

cont’d from page 33

Higher cow longevity indicates the animal’s biological functions and health are not impairing the length of her life. From a welfare perspective, this means longevity could be seen as a global indicator of animal welfare. However, there is lack of scientific knowledge about the relationship between welfare, longevity, profitability and productivity.

HERD WELFARE, LONGEVITY, PROFITABILITY AND PRODUCTIVITY

Along with other aspects of sustainable farming, animal welfare is part of certification programs. Even though the implementation of animal welfare solutions is linked with their economic returns, the relationship between animal welfare, herd performance and economics is unclear, and the information researchers have collected so far was obtained from a small number of farms.

To overcome the limitations of existing information, a third study was conducted to profile the welfare status of Quebec dairy herds based on welfare outcome measures collected on 2,696 farms between 2016 and 2019 through proAction. Researchers evaluated the relationship between the welfare profiles with longevity, profitability and productivity. Five unique herd welfare profiles were found, and the profile with the best overall welfare status also had the highest longevity, profitability and productivity (Figure 2).

This research confirmed issues associated with longevity and provided new insights for early selection of replacement candidates. The research also confirmed the value in adopting best management practices to improve welfare and longevity, as well as discover early life indicators to help dairy farmers identify cows that will have a long and productive life.

Gabriel M. Dallago

is a PhD candidate at McGill University.

Elsa Vasseur

is a professor at McGill University.

Valérie Bélanger

is the transfer officer at Novalait.

Shelley Crabtree

is the communications and KTT specialist at the Dairy Research Cluster.