The basic job of a dairy cow is to produce large quantities of high quality milk. It also doesn't hurt if she has some heifer (female) calves along the way. Calves are key because a cow doesn't start to produce milk until after she gives birth to her first calf which is often around 2 years of age. After the cow has calved and starts producing milk it is important to make sure that she receives the proper diet to enable her to perform to the best of her abilities. The goal is for her to make the most milk possible and feed efficiency is an important factor. So how do you get a high producing dairy cow? Surprisingly it begins long before she calves with the foundation for her future success being laid more than a year before she will ever produce milk.
Starting at around 2-3 months of age the mammary gland (milk secreting tissue) of a heifer calf enters a phase of allometric growth. Allometric growth is when one part of the body grows faster in relation to the rest of the body. So while some may see the diet and growth of heifers as a lesser priority due to the fact that they are not currently producing income the diet that heifers receive is as vital as that fed to lactating cows. All future success is dependent on the mammary development that occurs during this phase of allometric growth, which lasts about 7-9 months ending during puberty.
So what can a farmer do to ensure that their heifers excel during this phase? One key fact to remember is that what you feed your heifers directly impacts their body composition. If you feed them too much energy they will get fat, if you don’t feed them enough they will grow slowly or not at all. During the phase of allometric mammary development there is an increased impact on the developing mammary tissue. If an animal is putting on extra fat on their body there will also be a greater proportion of fat deposited in the mammary tissue. Fat deposited in the mammary gland reduces the density of milk secreting tissue potentially decreasing future production. If the animal is not receiving sufficient nutrients then there will be a reduction in the mammary development possibly stunting future production.
The best thing you can do to ensure maximum future production from your heifers is to feed them a good well rounded diet. They need enough energy and protein to grow big and strong as fast as possible but not so much energy that they get fat. While spending extra money on making sure your heifers get a proper diet can seem like a drag because they produce no current income, future production and income is usually increased when heifers are fed to properly satisfy their requirements.
This goes directly against the old adage “a penny saved is a penny earned.” The opposite can actually be true in this case. Scrimping on the diet you feed your heifers often results in decreases in future productivity and income. This is a case of investment now resulting in greater future earnings.