The cost of raising dairy heifer replacements represent 20 to 25 percent of the total costs of milk production. Important factors for managing the heifer enterprise include: keeping heifers healthy; developing consistent growth to attain target goals for frame size and body weight by 25 weeks of age without excessive body condition; and reducing feed costs.
Research conducted at the University of Minnesota Southern Research and Outreach Center in Waseca from 2003 to 2005 has evaluated feeding options for dairy heifers based on limit- or full-fed concentrate mixtures with or without access to long hay during part of the feeding period from 2 to 6 months of age. The goal is to provide consistent performances across all seasons of the year. All heifers were from three commercial dairies and housed in grower barns in four or five replicated group pens (six heifers/pen) per dietary treatment.
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Feeding Strategy Options
1. Concentrate diets containing alternative protein sources.
An 84-day study with 90 Holstein dairy heifers (av 222.2 lb BW; hip height, 37.9 in) 13 to 24 weeks of age using three different grower diets. Diets contained 18% crude protein (CP) concentrate mix (DM basis) fed up to a maximum of 5 lb/head/day with access to long hay (16.7% CP). The mix contained: 1) cracked corn (CC) — 66.25% of the diet; soybean meal-based pellet (P) — 32.5%, and fat — 1.25%; or 2) cracked corn — 31.25% and dried distillers grain mix (DDG) — 67.5% at 3.2 lb/heifer daily) and fat — 1.25%; vs. 3) cracked corn — 66.25%, pellet with 0.03 lb/heifer daily of urea partially replacing soybean meal (U) — 32.5%, and fat — 1.25% fat.
|Final BW, lb||398.3||406.2||396.4|
|Total Gain, lb||175.3||182.9||176.6|
|Final Hip Height, in||43.9||43.8||43.7|
Results — Overall heifer performance was not affected by the concentrate mix fed. Limit-feeding a concentrate mix to 5 lb/day with free-choice hay for postweaned dairy heifers supported good growth rates and is a very acceptable program. The addition of dried distillers grain (3.2 lb/day) or urea (0.03 lb/day ) as alternative protein sources in concentrate mixes to help feed utilization are acceptable options.
2. Full- vs. limit-fed whole-shelled corn and protein pellet diets with differing fiber levels.
A 112-day study with 96 Holstein dairy heifers (av 204.7 lb BW; 37.1 in hip height) 9 to 25 weeks of age using four grower diets. Diets formulated were: 1) LFWCP — 16% CP (DM basis) whole corn and pellet mix (6.5% ADF) limit-fed to 6 lb/calf (as fed) for 84 days and to 5 lb/calf daily from 85 to 112 days with free-choice alfalfa hay (20.8% CP); 2) FFWCP — 18% CP whole corn and pellet mix (5.5% ADF) full fed to 84 days with no hay and up to 5 lb/calf daily with free-choice hay from 85 to 112 days; 3) FFHF — 18% CP higher fiber whole corn with pellet (11.3% ADF) fed same as treatment 2; and 4) FFLF — 18% CP lower fiber whole corn with pellet (6.5% ADF) fed same as treatments 2 and 3.
|Initial BW, lb||205.1||204.1||203.8||205.6|
|Final BW, lb||457.6||482.9||485.9||483.4|
|Daily Gain, lb||2.3||2.5||2.5||2.5|
|Hip Height Change, in||7.8||8.0||7.8||7.7|
Results -– Heifers fed free-choice diets with no hay to 84 days averaged 9.82 lb feed DM/day and gained 0.5 lb/head more daily vs. those fed limit-fed concentrates (4.57 lb/day) with hay (5.33 lb/day). Between days 85 and 112, heifers that were switched from free-choice to limit-fed concentrates with hay did not gain as well as those limit-fed throughout. Over 112 days, limit-feeding concentrate grower diets with access to free-choice hay (av 6.25 lb/day) in group pens from 9 to 25 weeks of age resulted in a more consistent heifer performance without excess body condition when compared to full-fed concentrates without hay followed by a period of limit-feeding concentrates with full-fed hay.
3. Conventional vs. whole-shelled corn and pellet vs. complete pellet diets.
A study with 72 Holstein dairy heifers (av 189.8 lb BW; 36.8 in hip height) from 9 to 25 weeks of age. Diets formulated were: 1) GM — 16% CP grain mix (50% cracked corn, 30% pellet, 15% oats, and 5% molasses; 2) WCP — 16% CP whole-corn pellet mix (34% crude protein pellet; or 3) CP — 16% crude protein complete pellet. Grain mixes were limit-fed to 6 lbs/heifer daily with free-choice hay (16.9% crude protein). Diets were fed for 16 weeks.
|Final BW, lb||457.3||462.0||449.5|
|Total Gain, lb||264.5||274.3||260.5|
|Final Hip Height, in||45.0||45.1||44.6|
|Hay DMI/Day, lb||3.9||4.0||4.1|
Results -– There were no overall differences across dietary groups in daily grain intake (averaging 5.4 lb) and hay dry matter intake (just under 4 lb/heifer). Heifers fed the whole-shelled corn and pellet diet had a 3.6 and 5% higher total gain than those fed the grain mix and complete calf grower pellet, respectively. Heifers fed the whole-shelled corn and pellet diet used their feed 2.6 and 7.3% more efficiently than those fed the grain mix and complete calf grower pellet diets, respectively. Limit-fed concentrate diets, with access to free-choice hay, fed to heifers performed at a higher growth rate than anticipated. Feed dry matter intake averaged 2.9% of body weight for the 112-day feeding period.
4. Diets differing in forage quality and supplemented with a low-moisture block.
This 112-day study involved 96 Holstein heifers (av 203.1 lb BW; 37 in hip height) from 3 to 6 months of age. Diets were formulated to include a 16% CP grain mix fed to a maximum of 6 lb/heifer daily for the first 14 days of the study, then decreased to 4 lb/heifer daily for days 15 to 112. The limit-fed grain mix was fed with free-choice alfalfa hay at varying relative feed values (RFV). Treatments were: 1) 100 RFV; 2) LMB — 100 RFV hay plus a low-moisture molasses-protein block fed free-choice (30% CP with vitamins and minerals; 3) 131 RFV; and 4) 154 RFV.
|100 RFV||100 RFV + LMB||131 RFV||154 RFV|
|Final BW, lb||416.5||425.9||438.5||441.4|
|Total Gain, lb||213.4||222.8||235.4||238.3|
|Daily Gain, lb||1.9||2.0||2.1||2.1|
|Final Hip Height, in||44.3||44.1||45.3||44.7|
|Hay DMI/Day, lb||5.3||5.2||5.9||5.5|
Results -– Using a low-moisture block supplement with 100 RFV hay increased daily gain by 4% and feed efficiency by 2.3% compared to feeding 100 RFV hay without a block supplement. Using a 131 RFV hay compared to 100 RFV hay increased daily gain by 9% and feed efficiency by 3%. Using a 154 RFV hay compared to a 130 RFV hay increased daily gain by 1.4% and feed efficiency by 5.9%. Performance of all heifers were very acceptable, and an economic comparison should be the criteria to select the hay of choice when limit-feeding concentrates. The study demonstrated that feeding 6 lb/heifer daily of a 16% CP concentrate mix for the first 14 days followed by 4 lbs from day 15 to 112 when access to free-choice hay, provides sufficient protein and energy for acceptable daily gain and frame growth.
It is important to develop a nutritional management plan for group-fed dairy heifers between 2 to 6 months of age that will provide consistent performance whatever the season of the year with considerations for economic efficiencies. An initial summary of 897 dairy heifers raised at SROC over a two-year period from 2 days up to 6 months of age indicated an average daily gain of just under 2 lb/heifer, a final hip height of 45.1 inches, and a final body weight of 469 lb. These are very acceptable parameters for good quality 6-month-old heifers.
Research conducted by: H. Chester-Jones, J. Linn, and D. Ziegler, University of Minnesota
R. Larson and B. Ziegler, Hubbard Feeds, Mankato.
University of Minnesota Dairy Extension