DAIRY DECISION COLUMN
APRIL 14, 1998
AGGRESSIVE HEIFER GROWTH PROGRAMS

At the Midwest American Dairy Science Association meetings in late March at Des Moines, Iowa; several invited papers were presented on raising heifers by Michigan, New York, and Wisconsin researchers. Tremendous opportunities exist for improving Midwest dairy heifer operations.

Opportunity 1. The average age of heifers entering herd on DHI average 26 months of age. With aggressive management programs, heifers can enter the milking herd at 23 months of age, weigh over 1250 pounds after calving (large breed heifers), and produce higher levels of milk compared to older heifers. The minimum target age possible with top quality feed and management is 19 to 20 months of age according to Michigan State researchers. Pat Hoffman, University of Wisconsin researcher, reported it costs $1.81 per day to maintain and feed a heifer over 1100 pounds.

Opportunity 2. Grouping heifers is one key for optimal growth and management. The following age groups should minimize small heifers from being "bullied" by older heifers, allow optimal breeding to occur, and control feed costs. * Group 1: 3 to 4 months of age with ration 1 * Group 2: 4 to 6 months of age with ration 1 * Group 3: 6 to 9 months of age with ration 2 * Group 4: 9 to 12 months of age with ration 2 * Group 5: 12 to 15 months of age with ration 3 A.I. breeding and heat detection pen * Group 6: 15 to 21 months of age with ration 3 Pregnant animals (clean up bull if needed) * Group 7: Over 21 months of age, springing heifers receiving dry cow micro nutrients, support the fetus, and maintain desired growth If facilities allow, more groups of younger heifers would be desirable to minimize competition. Calves would be weaned and adjusted to a group prior to entering group 1 listed above.

Opportunity 3. Rations guidelines for accelerated heifer growth patterns are listed below which correspond to the ages and ration numbers above. Age (months) 3-6 6-12 over 12 Dry matter intake (lb) 7-13 14-19 20-28 Crude protein (%) 17-18 15-16 14-15 UIP (% of crude protein) 30-35 25-30 20-25 TDN (%) 70-74 66-70 60-65 ADF (%) 19-20 > 22 > 25 Calcium (%) 0.60 0.50 0.50 Phosphorus (%) 0.35 0.30 0.30 Limit the amount of pasture, corn silage, and wet haylage (over 60 percent moisture) to heifers less than six months of age. All forages should test over 0.55 Mcal net energy maintenance per pound of dry matter. Feeding 2 to 5 pounds of grain may be needed for heifers under one year with added protein supplement fed to heifers under six months of age (depending on forage quality and type). All heifers should be force-fed a mineral supplement and an ionophore (for growth and coccidiosis control).

Opportunity 4. Most dairy managers can quickly tell you their rolling DHI herd average or average milk yield per cow. Few managers can report average daily gains, wither or hook height, or body condition scores for growing heifers. For large breed heifers, average growth or gain should be 1.6 to 1.9 pounds per day, body condition scores below 3 prior to breeding, and over 52 to 56 inches wither height at calving. Small breed heifers should gain 1.3 to 1.5 pounds per day. Groups of heifers should be measured every four to six months and results compared to standard growth charts to determine if heifer growth slows down. In an Illinois field study, 32 herds monitored growth for two years and discovered heifers grew well up to six months of age and then "stalled out" due to low protein, too much heifer competition, low quality pasture, and parasite problems. Colorado workers reported if heifers freshen 100 pounds too light (for example Holstein calving at 1150 pounds instead of 1250 pounds), the light weight heifers produced 600 pounds less milk in the first lactation (nutrients were diverted to growth instead of milk production). In Summary Dairy manager should review their heifer growing system. For a typical Illinois herd with 30 heifers calving each year, a delay of three months in calving can cost $180 per heifer or $5400 plus the delay in milk income and increase in housing more heifers.

Two points should be remembered:

• Heifer hay and free pasture cost money.
• If you can not measure it, you can not monitor it and you can not manage it.