H.R. Conrad, W.P. Weiss, and J.W. Hibbs
Department of Animal Sciences
Dairy calves can be fed diets based on forage, rather than concentrate, and maintain acceptable growth rates and good health. Calves as young as 8 weeks old can use intensively managed pastures to obtain substantial amounts of nutrients. Calves between 8 and 12 weeks of age should be fed 1 to 2 pounds of concentrate in addition to pasture. Acceptable growth rates can be achieved with 3 pounds of concentrate plus pasture for older heifers. Another high forage system, called the Ohio High Roughage System, for raising calves is based on hay. Good quality legume hay comprises two-thirds of the diet, and concentrate makes up one-third of the diet. The maximum amount of concentrate fed is capped at 4 pounds/day. Growth rates of 1.7 pounds/day from weaning to 6 months of age have been achieved with this system. The high roughage system can reduce feed costs compared with a typical high concentrate diet.
Feed costs account for more than 50% of the total cost of raising replacement heifers. About 10% of the feed costs is for liquid feed (milk or milk replacer), and about 90% of the feed costs is from concentrates and forages. Until recently, low corn and protein supplement prices provided little stimulus for dairy producers to use high forage systems for raising young heifers. Grains are now at historically high prices, and increased forage feeding can help lower the soaring feed costs associated with raising replacments. Pasture or high quality hay can provide a signficant portion of the diet for calves between 8 weeks and 6 months of age. Certain precautions and guidelines are needed to make high forage systems work.
Pasture Systems. Intensively-managed grazing requires more day-to-day management choices be made by producers than with confinement systems. Young calves require even more attention when grazing. When grazing, concentrate should make up most of the diet until calves are about 3 or 4 months of age. At that age, calves should be consuming about 2.5 pounds of concentrate; the remainder of the diet can be high quality pasture. From 4 months of age until freshening, concentrate can be limited to 2.5 to 3 pounds/day when high quality pasture is available. The concentrate should be low in protein, contain the proper minerals (usually only salt, selenium, magnesium, and perhaps phosphorus), and have an ionophore such as Rumensin or Bovatec. A mix with corn or oats plus supplemental minerals is usually adequate.
The digestibility of forage from a rotational grazing system is very high. First growth grass harvested around May 1 can be more than 80% digestible; 15 to 20 days regrowth can be more than 65% digestible. Protein concentrations can range from 18% in midsummer to more than 30% in early spring. Most major minerals also are sufficient in high quality pasture.
One problem that sometimes occurs when young calves are grazing is scours. The high protein and soluble mineral content and low fiber content of early season pasture may initiate scours. Water turnover in the gut is increased when calves are fed pasture; the high potassium concentration in pasture exacerbates this condition. Proper balancing of minerals, feeding a low protein concentrate, and feeding about pound of mature grass hay/day will reduce the prevalance of scours when calves are grazing.
A second problem that can occur when calves graze pastures with white clover or alfalfa is bloat. In one experiment conducted at OARDC, 13 cases of bloat occurred when heifers were grazing ladino clover. None of the calves required treatment. Bloat in calves, however, does reduce feed intake, and that will reduce growth rates. To avoid this problem, pastures should be managed so that a mixed grass-legume sward is maintained.
The Ohio High Roughage System. For more than three decades, research was in progress at the Ohio Agricultural Research and Development Center (OARDC) aimed at raising healthy dairy calves with maximum dependence on good roughage and with minimum use of grain concentrate protein supplements and milk. From the results of this research, the Ohio High Roughage Calf Feeding System emerged. Until recently, with low corn and protein supplement prices, there was little economic incentive to use the High Roughage System. However, with present prospects for continued high prices for grain and protein supplements, the High Roughage System can help lower the soaring costs of raising dairy herd replacements. The system relies on homegrown forage. Production costs for forage are usually less than the costs of purchased concentrate. The system involves milk or milk replacer feeding limited to 5 to 7 weeks. After weaning, calves are fed a diet consisting of 2 parts high quality legume hay and 1 part concentrate. The High Roughage System encourages early development of rumen function, including both capacity for adequate hay consumption and the establishment of microorganisms needed for its digestion. In this system, the calf's requirements for high quality protein, amino acids, and B complex vitamins are provided by rumen microorganisms. The hay eliminates the need for complex, high-textured calf starters.
The economy of the High Roughage System is based on 1) the consumption and digestion of large amounts of good quality roughage made possible, in part, through early rumen development; 2) the use of low cost grain mixture fed in limited amounts; and 3) limited milk or milk replacer feeding, some of which can be colostrum.
A suggested whole milk (or a good quality milk replacer) feeding schedule is shown in Table 1. Extra milk is supplied during the first 2 weeks to meet the high energy needs of the calf during this early period. This tends to eliminate the loss of weight during the first 2 weeks. Feed one-half the daily amount at each of the two feedings. Calves can be weaned before 7 weeks when they are eating at least 1 pound of dry feed/day. Reducing milk feeding after 4 weeks will encourage dry feed consumption.
Use of a good milk replacer, all milk protein (at least 20%) and lactose (no sucrose or starch added) with at least 18% fat, can reduce the cost of milk feeding if substituted for whole milk after the second week. Extending the colostrum feeding period beyond 3 days will further reduce feeding costs. Fresh, frozen, or fermented colostrum can be used. Recent research has shown that providing the entire day's allowance of milk at one feeding does not reduce growth rates or impair the health of calves. This practice may be useful when labor supply is limited; however, calves should be observed more than once daily. Some calves may be unwilling to consume the double feeding of milk and will need to be fed twice daily.
| Table 1. Whole milk feeding schedule. | ||
| Days of age | Large breeds
(Holsteins) |
Small breeds
(Jerseys) |
| (Pound/day) | ||
| 0 to 3 | Nurse dam1 | Nurse dam |
| 4 to 142 | 12 | 8 |
| 15 to 21 | 10 | 6 |
| 22 to 28 | 10 | 6 |
| 29 to 35 | 10 | 6 |
| 36 to 42 | 10 | 6 |
| 43 to 45 | 8 | 4 |
| 46 to 49 | 4 | 2 |
| 50 to | 0 | 0 |
| 1 Either nurse dam or hand-feed colostrum.
2 Milk replacer can be used after 1 week. | ||
| Table 2. Grain feeding schedule.1 | ||
| Age | Large breeds
(Holstein) |
Small breeds
(Jerseys) |
| (Weeks) | (Pound/day) | |
| 0 to 4 | 0.0 | 0.0 |
| 5 | 0.3 | 0.2 |
| 6 | 0.5 | 0.4 |
| 7 | 0.7 | 0.6 |
| 8 | 1.0 | 0.8 |
| 9 & 10 | 1.3 | 1.1 |
| 11 & 12 | 2.0 | 1.5 |
| 13 & 14 | 2.5 | 1.8 |
| 15 & 16 | 3.0 | 2.0 |
| 17 & 18 | 3.3 | 2.2 |
| 19 & 20 | 3.8 | 2.4 |
| 21 & 22 | 4.0 | 2.6 |
| 23 & 24 | 4.0 | 2.8 |
| 25 & 26 | 4.0 | 3.0 |
| 1 To be used with free choice feeding of high quality hay beginning at 3 days of age. | ||
Good quality hay containing at least 17% protein, preferably hay that is soft, immature, second or third cutting containing at least 60% legumes, should be offered free choice after the third day. Always feed 10 to 15% more than the calf will finish. Feed bunks should be emptied daily (refused feed can be fed to older heifers). Weigh or estimate frequently how much hay is consumed (not fed). Based on hay intakes, adjust the amount of concentrate fed. The diet should be 2 parts hay to 1 part concentrate. Table 2 has a suggested grain feeding schedule that, when followed, will simplify maintaining a 2:1 hay-to- grain ratio when hay is fed free choice.
A concentrate mix that contains about 50% cracked or rolled corn, 35% ground or crimped oats, 13% soybean meal, 1% trace mineralized salt, and 1% dicalcium phosphate works well. Recommended vitamin supplementation is 10,000 IU of vitamin A, 1000 IU of vitamin D, and 100 IU of vitamin E per pound of concentrate.
When the amount of grain listed in Table 2 is fed during the weeks indicated, and if hay is fed ad libitum starting at 3 days of age, calves should consume a diet of approximately 2 parts hay to 1 part concentrate. Adjustments should be made for extra large and small calves so that a 2:1 hay-to-grain ratio is maintained. The maximum amount of concentrate fed is 4 pounds/day for large breeds and 3 pounds/day for small breeds (e.g., Jerseys). No limit is placed on hay consumption.
The regulation of the desired hay-to-grain ratio also may be simplified by chopping or coarsely grinding hay through a 3/4" or 1" screen, mixing it at a 2:1 ratio with concentrate, and feeding a completely mixed ration. The main disadvantage of this method is that the ration can be dusty. Water can be added at the time of feeding to prevent the irritation of dust and the unpalatability of the feed. Best results, however, occur with long hay.
Fresh water always should be provided. Calves fed dry, high roughage diets must be encouraged to drink water early in life (during the milk feeding period). In cold weather, warm water offered after milk feeding will help.
Data from experiments conducted at OARDC on the High Roughage System are in Table 3.
Approximately 40% of the total feed costs to 6 months was for whole milk. At current prices, the use of a good milk replacer after 4 to 7 days of age will reduce milk costs about 50% and the total feed costs to 6 months of age by approximately 20%. A major economic advantage of the High Roughage System is that most of the feeds fed are hay, cereal grains, and milk, which can be produced on the farm. When feed costs to 6 months of age are calculated on the basis of the estimated on-farm production costs, except the protein, mineral, and vitamin supplements, feed costs are reduced by 40% compared to feed costs based on purchased price of feeds.
| Table 3. Calf performance to 6 months, fed baled hay and grain (approximately 2:1). | |||
| Jerseys | Holsteins | Holsteins1 | |
| Whole milk, 7 weeks, pound | 2502 | 3502 | 436 |
| Alfalfa hay, pound | 550 | 820 | 704 |
| Grain, at least
14.5% protein, pound |
260 | 350 | 364 |
| Birth weight, pound | 53 | 98 | 85 |
| Final weight-6 months, pound | 237 | 369 | 361 |
| Gain, pound | 184 | 271 | 276 |
| Feed cost to 6 months3 | $94.23 | $133.55 | $138.33 |
| Feed cost to 6 months4 | $56.33 | $79.97 | $84.56 |
| 1 Thirty-five Holstein females fed milk and grain as
per suggested schedules in Tables 1 and 2, plus hay free
choice with extra milk the first 2 weeks.
2 Fed 1 pound of Holstein milk per 10 pounds of birth weight from birth to weaning. 3 Feed costs used (based on purchase or sale value) were: milk, $12.33/100 pounds; hay, $6.35/100 pounds, grain, $10.95/100 pounds. 4 Feed costs used (based on OSU crop production budget were: milk, $9.34/100 pounds; grain mix, $5.18/100 pounds, alfalfa hay, $3.55/100 pounds. | |||