Jaylor’s Ruminant Nutritionist, Janet Kleinschmidt, explains why adding fat to the diet of dairy cows become a common practice for most high production herds.

1. FEEDING FAT TO DAIRY
COWS

2. FEEDING FAT TO DAIRY CATTLE
Adding fat to the diet of dairy cows has
become a common practice for most high
production herds.
Why?
Energy demands exceed energy intake for the
first 80 to 100 days in milk (DIM).

3. FEEDING FAT TO DAIRY CATTLE

4. FEEDING FAT TO DAIRY CATTLE
Severe weight loss can lead to:
 Ketosis
 Fatty liver disease
 Reduced reproductive performance
 Decreased milk yield

5. FEEDING FAT TO DAIRY CATTLE
In times of energy deficiencies, grains can
provide an economical source of energy.
But fibre minimums and excessive levels of
fermentable carbohydrates limit the amount
that can be fed.
Fats on the other hand can provide over 2
times the amount of energy that carbohydrate's
can.

6. SOURCES OF FAT
• Fat sources in a dairy cows diet can be
broken down into 3 main categories:
1. Naturally occurring fat (grains & forages).
2. Commodity fats (oils seeds and animal and
vegetable fat).
3. Specialty or ruminally inert fats.

7. SOURCES OF FAT

8. SOURCES OF FAT
 All dairy rations will naturally contain 2.5-
3%.
 Commodity fats can affect rumen
fermentation by coating bacteria and feed
particles lowering fermentation.
 Specialty fats such as Megalac & Booster
Fat, are ruminally inert and frequently are
referred to as by-pass fat. They tend to be
very expensive.

9. SOURCES OF FAT

10. RESPONSES TO FEEDING FAT
Typically one or more of the following
responses will be seen when fat is added to
a dairy ration:
1. Milk yield may increase on average by 3 to 8% (1 to
2.5 kg).
2. Fat test can be maintained or increased by 0.2 to
0.3 percentage points.
3. Reproductive performance can be enhanced
because cows return to positive energy balance
sooner.

11. RESPONSES TO FEEDING FAT
4. Cows often lose >120 kg of body weight in early
lactation.
It can be very difficult to gain lost body condition
before the next lactation; this will affect future milk
production and reproduction. Fats can reduce this
affect.
5. Ketosis is a serious metabolic problem in early
lactation. Cows that lose more than one BCS will be
at risk of ketosis, fatty liver disease and death.
Energy status can be improved with fat
supplementation without risking excessive starch
levels and low fibre levels in the ration (acidosis).

12. BASAL FAT LEVEL 2.5-3.0%
COMMODITY FATS 2.0-3.0%
SPECIALITY FATS 2.0-3.0%
TOTAL 7.0-8.0%
HOW MUCH FAT CAN BE FED?

13. WHAT TYPE OF ADDED FAT SHOULD BE
FED?
The choice or combination of fats used will depend on several
factors:
1. Supplemental nutrient needs.
For example, if added protein is needed, whole soy beans
would be a good choice.
If fibre is lacking, fuzzy cotton seed would be ideal.
2. Facility constraint and handling.
For example, fuzzy cotton seed will not flow or auger in most
automated feed systems
3. Palatability of the fat product.
Most fat supplements are very palatable and readily
consumed by cows.
4. Cost of the fat supplement will have a strong influence over
its usage.

14. WHAT TYPE OF ADDED FAT SHOULD BE
FED?

15. Nutritional Considerations When Feeding
Fat
1. Adequate fibre form and level are needed to maintain rumen
digestion, particularly with unsaturated fats.
2. Ca should be increased to about 1% of the ration dry matter
to compensate for the formation of Ca soaps.
Mg should be increased to about 0.35% of ration DM, for the
same reason
3. Fat cannot be used by the rumen microbes. All fat “by-
passes” the rumen resulting in no additional microbial
synthesis. Therefore higher by-pass protein levels must be
fed in fat containing rations.
4. Added fats should be gradually increased in the ration to
allow for palatability changes and microbial adjustments.

16. Nutritional Considerations When Feeding
Fat
5. Supplemental fat should be limited in early lactation (3 to 5
weeks post partum). High levels of fat can depress total ration
dry matter intake.
6. Milk protein % is often lower when supplemental fat is fed.
This could be due to the effect on rumen microbes (less
microbial protein); reduced uptake of amino acids by the
mammary system; less blood flow to the udder or dilution of
protein by increased milk yield.
7. Liquid fats should be added to the concentrate prior to adding
to the TMR, rather than adding it to silage or the final base
TMR. Lower DMI and digestibility have ben reported when fat
is added to the forage.