Source: Ontario Veterinary College, University of Guelph
Beef cattle nutrient requirements can vary with different factors, such as the stage of production, age, breed, weight, and level of activity. These requirements are met by feeding water and roughages, and adding grains and supplements as needed.
Water: can be acquired by a cow through the moisture content of its feed and a direct source of water. The amount of water required by a cow differs with production stage, size of animal, activity level, type of diet, and other factors.
| Life Stage | Water requirement range (L/day) | Average typical water use (L/day) |
| Feedlot cattle (backgrounder) | 15 – 40 | 25 |
| Feedlot cattle (short keep) | 27 – 55 | 41 |
| Lactating cows w/ calves | 43 – 67 | 55 |
| Dry cows, bred heifers, bulls | 22 – 54 | 38 |
Water Requirements of Livestock, OMAFRA
DM: 2.5% of body weight
CP: 7 – 9 – 11 rule, where cows mid pregnancy require 7%, late pregnancy require 9%, and post calving require 11%
CP for feeder calves: 14 – 12 – 10 rule, where calves weighing 550-800 lbs require 14%, 800-1050 require 12%, and 1050-finish require 10%
Energy: 55 – 60 – 65 rule for a mature beef cow to maintain her BCS, where TDN energy must be 55% mid pregnancy, 60% late pregnancy, and 65% post calving.
- Energy can also be monitored by monitoring the cow’s BCS
Ca:P must be between 2:1 and 7:1
Mg and K should be at 2.2:1, and are used to make up the tetany ratio (K/(Mg+Ca), used to balance electrolytes).
Salt: recall NaCl is salt, and typically feeds only list Na. To determine salt can do 2.5 x Na. If Na is over 0.1, NaCl will be at least 0.25, which is adequate.
Forage Intake Guidelines:
Forage Intake Guidelines as a percent of body weight
| Life Stage | Straw and poor forage | Medium quality forage | Excellent quality forage |
| Growing cattle | 1.0% | 1.8 – 2.0% | 2.5 – 3.0% |
| Dry mature cows and bulls | 1.4 – 1.6% | 1.8 – 2.0% | 2.3 – 2.6% |
| Suckled cows | 1.6 – 1.8% | 2.0 – 2.4% | 2.5 – 3.0% |
Beef Ration Rules of Thumb, Alberta Department of Agriculture and Forestry
The last two months of a beef cow’s life are considered the finishing stage, and finishing cattle are fed high grain diets. When feeding high grain diets it’s important to have a high level of management to avoid compromising rumen health.
References:
Beef Ration Rules of Thumb, Alberta Department of Agriculture and Forestry
