NOTES ON BEEF COW HERD NUTRITION 1. Body condition scores (BCS) range from 1 [thin] to 9 [obese], with a range of 4 to 6 being ideal. Each BCS change is about 75 lbs. of weight change on a mature beef cow. 2. Nutrient needs during the lactation and breeding period are much greater than during the dry period. 3. Peak lactation occurs 60 to 90 days after calving and this should occur when forage quality and availability is greatest. 4. Feed costs are approximately 50% of the total costs of producing a weaned calf. 5. It is wise to sort cattle into separate management groups in order to match feed resources with cattle requirements. For example: a. Weaned heifer calves b. Bred heifers c. Coming two year olds and thin cows. d. Mature cows e. Dry cows versus lactating cows. f. Herd sires. 6. Daily dry matter intake of a cow is related to forage quality and her stage of production. When expressed as a % of cow body weight, expected daily dry matter intakes will be: a. Low quality forages (dry grass, straw, etc.) i. Dry cow 1.5% ii. Lactating cow 2.0% b. Average quality forages (native, brome or orchard grasses) i. Dry cow 2.0% ii. Lactating cow 2.3% c. High quality forages (alfalfa, silage or green pastures) i. Dry cow 2.5% ii. Lactating cow 2.7% 7. Weather changes including wind chill can dramatically alter a cow’s daily nutrient requirements. 8. Mineral supplementation is usually provided free choice to brood cows and normal consumption is about 3 lbs. to 5 lbs. per cow per month. Both macro and micro minerals must be supplied. a. Forages tend to be relatively good sources of calcium, while grains tend to be high in phosphorous. b. Soils influence trace mineral content of plants. Michigan soils tend to be deficient in cobalt, iodine, selenium and marginal in copper. 9. Dry matter losses of harvested forages depends upon length of storage time, storage method and feeding method. See tables 1, 2 and 3 on the reverse side of this handout. It will be necessary to harvest, store and feed greater amounts of forages to compensate for these losses. Table 1. Percent dry matter loss of round hay bales Storage Method Storage Period Up to 9 months 12 to 18 months Exposed Ground 5 – 20 15 – 50 Elevated 3 – 15 12 – 35 Covered Ground 5 – 10 10 – 15 Elevated 2– 4 5 – 10 Under roof 2- 5 3 – 10 Enclosed barn Less than 2 2- 5 From Huhnke, 1993 The lower value in each range represents well formed bales in low rainfall areas (>25 in./yr.) The higher values are for areas with higher rainfall (<40 in./yr.) and relatively high humidity. Table 2. Effect of storage system on d.m. loss of ryegrass hay stored 7 mo. Source of Loss Storage System Storage Animal Refusal Total Ground 28 22 50 Gravel 31 17 48 Tires 35 6 41 Rack 26 6 32 Rack with cover 12 2 14 Barn 2 1 3 From Redmon, 1996 Table 3. Dry matter loss of large round hay bales due to transporting and feeding Range Average Transporting hay 1–5 3 Feeding method Hay ring 1 – 20 10 No hay ring 5 – 45 20 Rolled out 5 – 25 15 Adapted from Wheaton, 1980; Anderson and Mader, 1985 Table 4. Effect of feeder type on intake and waste of round-baled hay Round Bale Feeder Type Ring Cone Cradle Hay DM disappearance Lb./cow/day 26.8 26.4 28.4 Hay DM waste/cow/day 1.6 0.9 4.2 DM intake/cow/day 25.1 25.4 24.3 Waste %, dm basis 6.1 3.5 14.6 DM intake, % cow body wt. 1.84 1.76 1.82 From Buskirk, et.al., 1999 Trailer 30.6 3.5 27.1 11.4 1.96