Limiting Forage Intake for Dairy During Drought
Recommended minimum forage intakes for dairy cattle during drought.
J. W. Schroeder, NDSU Extension Dairy Cattle Specialist Emeritus
When forage is in short supply and purchased forage expensive and unavailable, dairy producers may need to reduce forage intake to recommended minimum levels. Heavier feeding of concentrates or forage substitutes may be used to maintain nutrient intake. It is advisable, however, not to limit normal forage intake for dry cows or springing heifers.
Recommended minimum intakes are found in Table 1. Only normal forage (hay, silage, pasture or green-chop) of sufficient particle size should be used to meet minimum hay-equivalent needs. These are expressed on a pound per hundredweight of bodyweight daily basis and refer to pounds of air-dried forage with a 90 percent dry matter content or its equivalent. The suggested minimum forage intakes in Table 1 are given on both a hay-equivalent and percent of total ration dry matter basis for use in conventional or total mixed rations, respectively. Generally, the lower minimum forage intakes given should be used for only a limited period of three to four months, otherwise more problems with health, reproduction and milk composition or quality may be encountered. However, this lower minimum may be used for longer periods if fiber levels and, preferably, particle sizes are maintained by use of roughages, forage substitutes or concentrates with a relatively high fiber content. Even then, some depression in milkfat test and some increase in health problems may occur.
The majority of particles for a given forage should be 3/8 - 3/4 inch or longer. Alfalfa meal or pellets should not be considered in meeting minimum hay-equivalent needs, while alfalfa cubes or hay may qualify.
Table 1. Recommended minimum forage intakes for dairy cattle*
|Hay-Equivalent Intake** Lb/Cwt Bodyweight||Total Ration+ Dry Matter|
|Dry cows, springing heifers||1.8||80|
|Calves under six months||0.8||25|
|Under 1000 lb||1.5||50|
|1000 - 1800 lb||1.3||50|
|Over 1800 lb||1.0||65|
- *Refers to hay, haylage, silage, pasture or green-chop of normal particle size.
- **For use in feeding conventionally.
- +For use in feeding total mixed rations.
- ++This level may be used for longer periods if acid detergent fiber levels in the total ration dry matter is kept at 20% or higher, preferably with ingredients of reasonably coarse particle size.
Purchased hay often can be an economical source of nutrients. This is especially true when adverse weather is not widespread and concentrate prices are relatively high.
Carryover hay or silage from previous years can usually be purchased at lower prices than material from the current harvest season. Generally, old-crop forages will equal new crop material in overall nutrient content. However, they contain less carotene or vitamin A activity and vitamin E. Ration should be balanced to account for the lower vitamin content in older, carryover forages.
When hay or forage prices are not economical, purchases can be limited to those necessary to meet recommended minimum intakes. If purchased forage is a more economical source of nutrients than concentrates or forage substitutes, then buy enough to maintain usual hay-equivalent intakes.
Several aspects of quality should be considered when purchasing forage. If economically feasible, purchased forage should be of such quality that the total forage dry matter fed to dairy cows will contain a minimum of 60 percent TDN on a dry matter basis.
Grass hays often sell for appreciably less than legumes. These sometimes are better buys if they are needed to supplement home-grown hays or haylages containing high-protein legume forage.
When no high quality alfalfa hay or haylage is available on the farm, consider purchasing enough good alfalfa to feed 3-5 lbs per head daily. Feeding even these limited amounts of alfalfa may help improve feed utilization and performance. Alfalfa should contain at least 19-20 percent crude protein on a dry matter basis to be considered for this use.