The productive lifetime of the dairy cow
The average productive lifetime of the dairy cow in intensive milk production is decreasing around the world, with averages like 2.4 lactations in the US and Denmark. This shorter lifespan is mainly a result of what has generally been considered as sound economic decisions on profitability. However, much of the decrease in dairy cow longevity is mainly the result of involuntary culling due to poor health or fertility problems. This can lead not only to lower profitability, but also to concerns from consumers, who are becoming increasingly aware of animal welfare issues.
Lifetime Daily Yield (LDY) as an indicator of performance
Instead of focusing only on milk yield per lactation, it can be beneficial to also think in terms of volume of milk given over a cow’s lifetime. Lifetime daily yield (LDY) i.e. yield per day from birth to culling, can be used as an overall indicator of technical performance at the farm, as it averages out total milk production over every day a cow has been alive. Cows that start milking at a young age, have a short calving interval and are healthy enough to last several lactations, will have a much higher LDY than those who are older at first calving, do not get back in calf very quickly and have poor longevity. A high yielding cow that doesn’t make it to the third lactation because of poor health or fertility will have a lower LDY than a cow that reaches fifth lactation but with a lower average yield per day.
The four things to take into account when calculating lifetime daily yield are:
- milk yield
- age at first calving
- calving interval/lactation length, and
- involuntary cullings/number of lactations.
The starting point to increasing daily lifetime yield is reducing age at calving. A first calving age above 25 months has a negative impact on lifetime performance, and is tying up excess capital and increasing the farm’s carbon footprint. The goal is to have the first calving at the age of 24 months, and through good young stock rearing practices, it is possible to inseminate the heifers at an average age of about 14 – 15 months. However, it is always important to measure the height and the body weight of the heifers to monitor the growth. A young calf must attain at least 70 percent of calving time weight at the time of first insemination.For the prevention of problems at calving time, it is of utmost importance that the heifers are well developed. A young calf must attain at least 70 percent of calving time weight at the time of first insemination. The optimal time of first insemination is more dependent on body weight than age. Some heifers may be able to achieve the desired weight in 14 months; others may achieve the same in 16 months of age. We recommend following the Penn State University Heifer Growth Chart.
Another issue that is often overlooked is record-keeping of involuntary cullings. If you don’t measure you can’t manage, so it is important to keep good records of all cows that have to leave the herd because of lameness, mastitis, fertility or disease. Gathering that information will draw attention to problem areas, and might over time help to change the mentality of only focusing on yield per lactation.
LDY is not an indicator of profitability, as the farmer milking his cows for many lactations may be spending a fortune on vet bills, but it is a very good indicator of performance. And it puts the cow’s health and fertility in the centre.
The cost of involuntary culling
Keeping a healthy cow in the herd for another lactation, instead of culling her, increases her LDY with as much as two liters, depending on the situation. An additional lactation increases the amount of time available for the cow to pay back the investment in rearing her (15-20% of the total expenses related to milk production) and start making profit. In the US involuntary losses of cows in early lactation is estimated to cost $500 to $1000 per cow, and this is just the tip of the ice berg. The incidence of the underlying diseases is a lot higher than what can be seen in the culling rate.
Charlotte Hallén Sandgren, veterinarian and Dairy Development Director at DeLaval International has worked many years with animal health and welfare, among other things as national project leader for the Swedish Dairy Cattle Health programme. She has become increasingly concerned with the decreasing average productive lifetime of the dairy cow. It is a waste of resources, investing so much in rearing the calf, and then loose her before she has reached her peak condition, because of production diseases and less than optimal barn designs.
“It is more profitable to keep the animals healthy, so that we can decide which cow to cull and when, and not have to rear and introduce all heifers into the herd, regardless of their potential.”
Putting the dairy cow and her environment in the center
The concern for dairy farm profitability and animal welfare has led to a commitment from DeLaval to host a conference on this subject at their farm in Tumba, Sweden on 28-29 August.
“There is a lot of knowledge out there and a need for a holistic approach. It is time to put the dairy cow and her environment in the center and get people from different parts of the world and different fields of expertise together, to learn from each other. We can then take these findings to the farmers, so that they can use this knowledge on farm.”
Cutting-edge knowledge in replacement economy, animal health, management and barn design, and more will be presented by experts from North America, Europe and New Zealand. Together they will identify risk factors in the barn and the most profitable and efficient management practices.
“We [DeLaval] want to make sure that we know what is important, what is best for the cow and for the farmer, so that we know how best to help improving farm profitability with our expertise,” says Charlotte Hallén Sandgren.
The Cow Longevity Conference 2013 will cover four topic areas:
• Increasing the cow's lifetime – why bother?
• A cow’s view of barn design
• Health management to reduce involuntary culling
• Critical periods during the cow’s life
For more information about the Cow Longevity Conference, go to the Conference web site.
The conference will be covered by Milkproduction.com, and reports will be available here on the web site.
Download the proceedings here (pdf 2,6 MB)
To read more about what will be covered at the conference read interviews with some of the speakers under each of the topic area pages above.