The document discusses feeding and evaluating the nutrient content of cow feed. It outlines several key points: 1) Effective feeding is important to maintain cow fertility, production and profitability. Feeds must meet cow requirements for energy and nutrients. 2) Feed samples should be taken and tested to determine nutrient composition, including dry matter, protein, fiber and energy levels. Factors like weather and quality can impact nutrient content. 3) Various methods are used to analyze feeds chemically and determine digestibility, including proximate analysis, Van Soest method, and digestibility trials using nylon bags or artificial rumens. This helps evaluate the quality and energy value of different feeds.

1. Cow Feeding Evaluation
Prepared By:
Dr. Irshad A.
PhD Scholar
Department of MSC and Tech
VCRI-Namakkal
Course : LPM-801
Advances in Cattle and Buffalo
Production and Management

2. Introduction
→Managing high yielding cows to meet their energy intake
requirements for peak milk production is a major challenge
facing dairy farmers.
→Underfeeding dairy cows leads to excessive negative energy
balance and subsequent fertility problems
→40 and 60 percent of the total cost of producing milk is from
feed cost
→Effective feeding is important to maintain fertility, production
and profitability.

3. Feeding Evaluation
Feeds supplied
to the cow
Cow
requirements
Diet
evaluation

4. Feed Nutrients
Growing conditions, such as excessive rainfall or drought, can
affect the nutrient content of feeds, especially forages.
Other facts such as musty odor, unusual amounts of foreign
material or pests present in the feed, and a high level of leaf
shattering on forages etc… can affect quality
Excessive amounts of some substances like Nitrates can be
harmful to animals.
• The most important tests to be done on feed grains are
moisture, protein, and energy content.
• Test forages for moisture, protein, acid detergent fiber and
neutral detergent fiber.

5. Sampling of Feed
Take representative samples of the feed to be analyzed.
Take random samples of hay from at least 20 bales. Insert the
sampling tube into the center of the bale.
About 15 samples from silage and 5 from grain will usually
give enough to be representative of the entire lot.
Samples of silage or total mixed rations should be taken from
the silage feeder or feed mixer as it is being fed.
Avoid the top of the feed because it is drier than the entire
batch.

7. Sampling of Feed
• Mix the samples from one type of feed and take a subsample
from the mixture for analysis.
• Seal the samples in polyethylene freezer bags; store dry samples
in a cool area.
• Freeze samples that contain more than 15 percent moisture.
Send the samples to a testing laboratory as soon as possible.

8. Feed Analysis Measures
Dry matter (DM)
Crude protein (CP)—the total of both true protein and non-
protein nitrogen.
Insoluble crude protein (ICP)—the amount of indigestible crude
protein in the feed resulting from overheating.
Adjusted crude protein (ACP)—calculated value, adjusted for
insoluble crude protein.
**If the ICP/CP ratio exceeds 0.1, use this value instead of crude
protein when balancing a ration.

9. Feed Analysis Measures (Cont…)
Neutral detergent fiber (NDF)—relatively insoluble material
found in the cell wall of plants, which may be used to predict
feed intake.
**A low NDF is desirable.
Acid detergent fiber (ADF)—measures the least digestible part of
the feed; includes cellulose, lignin, silica, insoluble crude protein,
and ash.
**A low ADF is desirable.
Digestible dry matter (DDM)—percent of forage that is
digestible.

10. Feed Analysis Measures (Cont…)
Net energy (NE)—It is the energy left after determining the
energy lost through the feces, urine, gas, and heat generated by
metabolism.
**an indicator of the true value of a feed.
Total digestible nutrients (TDN)—the total of the digestible parts
of crude fiber, protein, fat, and nitrogen-free extract.
Dry matter intake (DMI)—estimated maximum consumption of
forage dry matter by the animal.
**It is shown as a percentage of body weight.
Relative feed value (RFV)—an evaluation of the quality of hay
and haylage by combining into one number digestibility and feed
intake.

11. Utilization of dietary energy by animals

12. Cow requirements
Maintenance
Production
Requirement

13. Methods for Feed Analysis
Chemical Analysis
Digestibility Trials
Estimation of Energy Contents
Evaluation of Protein Quality

14. Chemical Analysis
1. Proximate Analysis
A. Water/Moisture
B. Crude Protein
C. Ether Extract
D. Crude Fibre
E. Nitrogen Free Extract
F. Ash/Mineral Matter
2. The Van Soest method
of analysis
A. Cell Wall
B. Cell Contents

16. The Van Soest method

17. Digestibility Trials
1. Conventional Type
A. Direct method
B. Indicator Method
2. In Vivo Technique
A. Nylon/Dacron Bag Technique
B. In Vivo Artificial Rumen
(Vivar) Technique
A digestion trial involves an experiment by which the
amount of nutrients actually digested and absorbed from a measured
amount of feed consumed by an animal determined.

18. Conventional Type of Digestive Trials
Animal Feed Excreta Feed Digested
A. Direct Method
Done in Metabolic Crates
They are actually a specially
designed stall or box large
enough for the experimental
animal to house in controlled
condition during experimental
period.
Digestibility Coefficient = Kg of Nutrient eaten – Kg of Faeces X100
Kg of Nutrient eaten