In good times or bad, your dairy's replacement heifers represent the future of your herd. It makes no difference if the price of milk is up or down or what the price of feed happens to be, your baby calf and heifer raising program should be high up on the list of management priorities. It's not always easy to see that what you do to those calves today will affect their production two to five years down the road. Calf and heifer raising must be a long-term commitment.
I can speak from first-hand experience how much trouble not having enough replacements for your dairy herd will cause you years down the road. Every dairy herd must eventually cull every cow in the herd, and you have only two choices for how to replace those cows: raise them yourself or buy them from someone else. Both options are costly, but at the end of the day, in most cases, raising your own replacements is the less expensive way to do it - provided you do it right. Even if you do everything right, you never get all your heifers to complete that first lactation.
The single most important management factor for getting calves off to a healthy start and decreasing preweaning mortality is the feeding of colostrum immediately after birth. Recommendations for the feeding of colostrum include 3 to 4 four quarts immediately after birth, followed with an additional 2 to 4 quarts at about 12 hours of age to supply the calf with adequate levels of immunity. The ability of the newborn calf to absorb the immunoglobulins from colostrum decreases rapidly after birth, and the effectiveness of colostrum is greatly diminished if fed after 16 hours of age.
Over the years there have been research trials attempting to establish a positive correlation between colostrum feeding and mature milk production. The results of these studies have been variable. However, it is well established that the passive immunity supplied to baby calves by way of colostrum intakes at the time of birth greatly improves their survivability.
Recent research has shown that doubling a baby calf's birth weight by two months of age can increase first lactation milk production by over 1,000 pounds of milk. One study conducted at the Miner Institute, in Chazy, N.Y., concluded that by increasing nutrient intake prior to weaning resulted in over 1,500 pounds of milk at 200 days in milk compared to herd mates that were fed only conventional levels of milk prior to weaning.
If you have a Holstein heifer calf born weighing 100 pounds, your goal is to have her weighing 200 pounds eight weeks later. Gaining 100 pounds in 56 days requires an average daily gain (ADG) of 1.78 pounds. That's an aggressive ADG, but certainly not impossible to achieve. To achieve a doubling of birth weight by two months of age requires feeding milk replacers with 26 to 28 percent protein levels with fat levels from 15 to 20 percent. By the time the calf is a week old the milk replacers must be fed at 2 percent of the calf's body weight. In other words, the bigger the calf gets, the more powder has to be fed.
The question, of course, will invariably surface amongst cost-conscious dairy farmers as to the cost-effectiveness of accelerated growth rates using expensive milk replacers. Dairy farmers often spend more time focusing on the initial cost of raising the calf rather than the economic benefits of getting a heifer fresh and into the milking parlor a couple months earlier than they might otherwise. Ultimately, there is much greater potential for profit increase by reducing the heifer inventory on a dairy farm by improving nutrition and management of calves at the time of birth through weaning.
A Cornell University study shows that the total investment in a heifer that was freshened at 22.2 months of age compared to one that freshened at 24.5 months of age was very nearly identical even though the preweaning cost per pound of gain was almost 20 cents per head per day more (Table 1). The economic advantage comes from a more efficient growth rate with the intensified nutrition.
Research has determined that the protein and energy ratio in heifer diets is fairly constant throughout the two years of growth. To optimize the efficiency of nutrient utilization and structural growth, the recommended ratio of crude protein (CP) to metabolizable energy (ME) is 63 grams CP to 1 Mcal ME from 4 to 10 months of age. The CP level of a growing heifer ration comes out to about 14 percent while the ME level is about 1 Mcal per pound of feed. The CP requirement drops to about 60 grams during the second year of growth while the ME remains the same.
This ratio remains the same regardless of which breed of heifer is being raised. What differs is the amount of dry matter that each will consume. For instance, a 6-month-old Holstein heifer should weigh about 390 pounds while a Jersey heifer will weigh about 280 pounds. The Holstein will consume about 10 pounds of dry matter daily while the Jersey will consume about 8 pounds. The total grams of protein and Mcals of energy will be more for the Holstein since she's eating more feed compared to the Jersey. However, the ratio of the CP:ME will be the same for each breed. This allows for a straightforward application of a single TMR for heifers from 4 months to breeding age, and then again another one for breeding age to springing.
Cornell's work suggests that increasing colostrum status and nutrient intakes in baby calves will have a much greater impact on lifetime milk production than genetic selection. Dairy farmers should work closely with their feed sales professional or nutritional consultant to make sure their calf and heifer diets are adequate to meet the growth requirements that will get those heifers into the barn as early as possible to begin generating income.
The author is a dairy nutritional consultant and works for Central Connecticut Farmer's Cooperative in Manchester, Conn.