When planning a feeding program for a dairy herd, it is important to recognize the difference in feeding dry cows versus feeding lactating cows. This is important not just to ensure proper nutrition for the dry cow, but also to help producers keep their feed budget in check.
The right feeding program will keep a dairy herd performing at its best in the long run, whether dry or lactating, and will keep the producer’s bottom line where it should be.
In order to properly feed for the dry period, producers have to understand the dry period. Restoring body energy and nutrient reserves is more efficient if accomplished during late lactation rather than during the dry period.
The number of mammary secretory cells is a major factor affecting milk yield. These secretory cells normally proliferate during the later part of the dry period. The dry period is necessary, however, to allow the mammary gland to go through a normal period of involution and to ensure that the mammary cell numbers continue to proliferate normally during early lactation. A short or absent dry period greatly reduces the number of secretory cells in the mammary gland.
According to dairy industry experts and Penn State University Extension, the amount of milk produced during a cow’s lactation can be influenced by the length of her dry period. Many studies have shown that cows dry for 60 days give approximately 250 pounds more milk the following lactation, compared to cows dry fewer than 40 days, which produce around 500 pounds less milk the following lactation.
Dry periods longer than 60 days show only a moderate decline in milk production compared to those cows dry 60 days. The reason for keeping dry periods close to 60 days is short dry periods do not allow enough time for mammary gland involution while long dry periods result in excess body condition.
Dry cows should be fed an adequate ration to keep their condition scoring between 3 and 4 on the BCS scale (with 1 being too thin and 5 being too fat).
This body score on a dry cow can be achieved by feeding a relatively low energy ration that provides adequate, but not excessive, levels of protein, minerals and vitamins. Providing proper levels of these nutrients allows cows to calve with adequate, but not excessive, body fat, protein, and metabolite reserves.
Once a cow freshens, she will need to rely on her energy reserves for the next six to eight weeks to achieve maximum milk production. If the dairy cow does not have these reserves, she will develop a severe negative energy balance, which will limit her peak milk production and cause excessive body weight loss.
It is also recommended that a dry cow’s ration should include good quality grass hay and between 3 to 5 pounds of grain or other concentrate per head daily.
The University of Missouri Extension cautions producers against over-conditioning during dry periods. Over-conditioning usually begins during the last three to four months of lactation when milk production decreases, but grain intake remains too high. Prolonged dry periods and overfeeding grain or corn silage during the dry period also may lead to over-conditioned cows. An over-conditioned cow would score 4 to 5 on the BCS scale.
With proper feeding, dry cows will be well conditioned and ready to go when it comes time for them to freshen.
