There are 3 primary physical limitations on production in robotic milking systems. The first is milking capacity, or the number of robots. The second is housing capacity, or the number of stalls. The third is the market, or how much milk the market will accept.
Secondary limitations determine how completely each of the primary limitations is used. For example, higher production per cow can increase the productive capacity of each robot. If cows move through the system 24 hours a day, 7 days a week, the number of animals per stall can be increased. In a quota market, there is no point in increasing the number of cows or production per cow if you are penalized for the sale of extra milk. Feed availability may be limiting, but purchased feed can stretch that secondary limit.
Robotic milking systems are too expensive to operate below capacity, and they don’t perform well when they are over capacity. Maintaining the optimum number of cows is a key to maximizing the 3 primary physical limitations. This requires realistic culling expectations, judicious use of sexed semen vs beef semen, and controlling seasonal fluctuation.
Realistic culling expectations
We determined that a customer had a 20% cull rate for the past year. That’s a great! Or is it? The nutrition consultant pointed out that we were not meeting projected cow numbers because we were not realistic about culling expectations. We could project growth with a 20% cull rate. But we couldn’t maintain it long term because we were keeping cows we shouldn’t have. That left no room for voluntary culling. It is possible, and maybe profitable, to achieve a 20% cull rate. It’s better to plan for 30% or more.
Judicious use of beef on dairy
A realistic cull rate is an important tool for planning use of beef semen, conventional semen, and sexed semen. It’s tempting to use more beef when that black calf puts $800 in the checking account now, while the black and white heifer calf takes a lot longer to generate income. We are all know the high cost of raising heifers we don’t need. There are too many robot barns waiting for the herd to grow while 30% of the pregnancies are from beef semen. Fill the barn first, with a realistic cull rate and at least 10% more heifers than you think you need.
Controlling seasonal fluctuation
Look beyond the number of calves produced every year, to the number of calves produced every month. If you freshen a lot of cows in spring and fall, a lot of calves are born in spring and fall, and those calves will freshen 24 months later in spring and fall. Seasonal fluctuation will not solve itself. Break the cycle by using sexed semen to create more heifer calves in the months when you need more cows. Then use beef semen to reduce the number of heifer calves born in the months when you have too many cows. It will take some time, but fluctuating cow numbers can be managed. This keeps the system consistently full – whether the primary limitation is robots, or stalls, or market. Seasonal fluctuation optimizes some systems – like grazing. The same tools can be used to maximize seasonal fluctuation. The point is, seasonal fluctuation should be managed – not accepted.
Purchased Replacements
Buying and selling replacements are also tools to manage cow numbers. There may be value in maintaining a closed herd. Availability of replacements may be limited. But filling the barn now may be more profitable than filling it a year from now. Some very successful herds plan to purchase replacements. Other very successful herds plan to sell replacements.
Cow Corner can help you determine the optimum number of cows for your system. I can also help you project cow numbers into the future, and develop a program to change cow numbers to match future needs.