If you tuned into President Donald Trump’s Inauguration or kept up with any news surrounding the inauguration, you may have noticed that while security efforts were high, no one was named as the designated survivor.
The U.S. has a tradition of naming a designated survivor, typically someone in the president’s cabinet, who remains in a secure location during a large event (like the inauguration) to ensure that person is available to take over the presidency in case of a catastrophic event. While I imagine choosing a designated survivor is difficult, there are general principles that are used to make the selection. In a similar fashion, dairy farmers follow general principles when deciding which cows stay in the herd, or which cows are the “designated survivors”.
For farmers, deciding which cows stay in the herd is a management decision largely based on economics. The “designated survivors” on a farm are the cows that are most profitable, the cows that are high producing, have good health, and reproduce successfully. These are typically the older, mature cows. Thus, one way to improve the profitability of a herd is by improving productive life.
Productive life is defined as the time from first calving, when the cow begins producing milk, to when the cow is culled. The average lactation number can be used as an alternative for productive life, so the more lactations a cow completes, the longer her productive life. If we break down a farm’s milk production by lactation, it is the healthy, mature cows that have the highest production. Dr. Albert De Vries from the University of Florida created a model published in the Journal of Dairy Science in 2020 that demonstrated the key factors that influence the optimal productive lifespan from an economic perspective. De Vries’s model used total herd structure costs that consider replacement cost, lack of maturity cost, aged cow cost, genetic opportunity cost, and calf value opportunity cost. Considering these 5 costs, De Vries concluded that the optimal productive lifespan is 5 years or 5 lactations. However, according to Dr. Gavin Staley with Diamond V, the average productive life for dairy cows is actually much shorter than that. For many dairy herds, the average is 2.6 lactations.
To improve productive life, Dr. Staley suggests focusing on creating “platinum” heifers that turn into mature and healthy “golden girls”. Any successful dairy program begins with a successful heifer management program. Heifers that are well-grown are the ones that turn into high-producing cows. It’s important that heifer growth is not rushed. Weighing heifers at regular intervals is important to ensure that heifers are achieving acceptable average daily gain, 1.7 to 2.2 lb/d, and that they reach the goal breeding weight in a reasonable amount of time. The Dairy Calf and Heifer Association recommends breeding heifers for the first time when they reach 55% of their mature body weight, and after calving heifers should be 85% of their mature body weight. The average mature body weight will vary between herds but can be determined by finding the average weight of cows in their third or fourth lactation in your herd when they are at peak lactation.
Investing in heifer growth will increase the likelihood of your animals making it past the breakeven point, which is when they have brought the farm enough income to cover the cost of their heifer rearing. For most cows, this breakeven point doesn’t occur until their second lactation. These cows that make it to their second lactation and greater are what Dr. Staley refers to as the “golden girls”. To be most profitable, these golden girls should make up a large percentage of cows in your herd. According to Dr. Staley, the demographics of a herd by parity should look like a Christmas tree, or a “lactree”. The top of this lactree is where you find cows in their fifth and sixth lactations. To establish an extended productive life model in a herd, these cows must make up 12 to 15% of your herd demographic. Overall, to implement the productive life model farmers should strive for about 45% of their herd to be made up of cows in their third lactation or greater. While it may be tempting to cull older cows as they may experience more lameness or health challenges, or because you want to make more room for incoming heifers with greater genetic potential, these are the cows that produce the most milk and bring in the most money for the farm. Implementing proactive preventative management strategies can aid in avoiding premature culling and keep more “golden girls” on the farm.
While on a dairy farm we would never choose just one designated survivor like the U.S. government does, the ultimate goal is to raise our animals to all be worthy of being a designated survivor. We want to grow strong and healthy heifers so the decision of what cows need to leave the herd is a difficult one. The best-producing herds are the ones that have a majority of their cows in their third lactation or greater, and this stems from a successful heifer rearing program. Extending productive life can be difficult to accomplish and takes time, but in the end, it results in herds that are profitable, sustainable, and worthy of your investment as designated survivors.
— Emily Bourdeau