Feed intake is usually characterized as dry matter intake (DMI) to compare diets of variable moisture concentrations. There are several factors that affect dry matter intake (DMI) of cattle these include: physiological, environmental, management and dietary factors.
Cattle will normally consume 1.4 to 4.0% of their body weight daily depending upon the quality of feed:
- Cows will consume between 1.8% and 2% of their body weight on a dry basis of a low quality feed.
- Cows will consume between 2.0% and 2.2% of their body weight on a dry basis of an average quality feed.
- Cows will consume between 2.2% and 2.5% (during lactation it may be as high as 3 %) of their body weight on a dry basis of a high quality feed. (University of Nebraska, Beef Cattle Production website)
Amount to feed
Cows should eat to capacity. For every 100 kg live weight, cattle will eat an average of 2.7–3 kg of dry matter daily if the ration is palatable, but this will vary throughout the feeding period.
Physiological Factors affecting feed intake:
Frame size and percentage of body fat are considered in equations to predict feed intake by cattle. Condition scoring your cattle is also a useful management tool, as a thin cow (condition score = 1 or 2) will consume more than a fleshier cow (condition score = 3). Other physiological factors include the sex, age and if the animal is dry or lactating.
Sex of the animal has a limited affect on DMI. One of the most important factors that affects intake is the reproductive status of the animal where a lactating cow will eat 40 to 60% more than a dry cow.
The age of the animal also affects intake, as older animals will consume more feed that younger animals as young cows have less rumen space. One of the most important factors affecting intake is whether the animal is lactating or not, as lactating cows will eat 40 to 60% more than dry cows.
Environmental Factors affecting feed intake:
Intake can increase up to 30% in colder temperatures and can decrease by 30% under hot/humid temperatures. Adverse conditions like mud and snow can also decrease intake by up to 15%.
Management and Dietary Factors affecting feed intake:
Nutrient deficiencies can decrease intake by 10 to 20%. Growth promoting implants tend to increase feed intake. Feeding monensin typically decreases feed intake.
The following are some feed intake guidelines:
Forage Intake Guidelines (as per cent of body weight)
|Straw and Poor Forage||Medium Quality Forage||Excellent Quality Forage|
|Growing and Finishing Cattle||1.0%||1.8 to 2.0%||2.5 to 3.0%|
|Dry Mature Cows and Bulls||1.4 to 1.6%||1.8 to 2.0%||2.3 to 2.6%|
|Nursing Cows||1.6 to 1.8%||2.0 to 2.4%||2.5 to 3.0%|
Some other factors that will affect the voluntary consumption of forage are:
- Stage of maturity of the feed – the fibre component of forages increases with maturity reducing intake
- Weathering – mold growth usually reduces consumption
- Species – grasses are usually consumed in lesser amounts than legumes
- Physical form – grinding increases forage consumption, particularly with low quality forages
- Grain Feeding – will usually depress forage intake, especially when grain is fed before forage
- Fermentation – consumption of DM from silage is usually less than if the same quality of feed were fed as hay
Grain Intake Guidelines
|Desired ADG (lb.)||Grain (% BW/day)|
|Growing Cattle||0.5 to 1.0||0|
|2||2.0 to 2.2|
|Finishing Cattle||3.0||2.0 to 2.2|
|Roughage Type||Recommended Grain Intake (lb./day)||Recommended Grain Intake (kg./day)|
|Dry Beef Cows||Straw||4.0 to 8.0||2.0 to 4.0|
|Suckled Beef Cows||Straw||6.0 to 12.0||3.0 to 6.0|
|Good Hay||0.0 to 8.0||0.0 to 4.0|
|Bulls||Straw||6.0 to 10.0||3.0 to 5.0|
|Good Hay||1.5 to 3.0|
Why is this important?
In most herds, nutrient intake in early lactation is one of the main limitations to high production and good reproductive performance. Inadequate dry matter intake (DMI) will limit peak production and, if body condition loss is excessive, first ovulation can be delayed.
Article Courtesy of albera.ca