Drought: Commodities

Dairy Cattle — Feeding whole cottonseed to dairy cows and replacements

Whole cottonseed is a very popular feed for dairymen. Usage has increased during the past 10 years. It can be fed just as it comes from the gin without processing or may be pelleted before feeding. Pelleting improves substantially its handling properties especially the ability to flow with augers. Pelleting also reduces the bulkiness and allows more to be hauled in a truck or freight car. Seed prices are a function of supply and demand. Demand may be for use as feed or to be crushed for oil. Whole cottonseed is an excellent feed for dairy cattle due to its high level of fiber, protein and energy (fat) in a compact package. Whole cottonseed can also be utilized to stretch limited forage supply. Dairymen need to capitalize on this situation as much as possible. Here are some factors to consider when feeding whole cottonseed that limit the amount that can be fed safely. Some of these are gossypol, high fat content, and the potential for aflatoxin. Whole cottonseed should be clean, dry and stored in a dry place, If long term storage is being considered they should not be stacked too high so as to prevent heating and or moister build-up.

The primary factor that limits the amount that may be fed is gossypol. Gossypol is a yellow polyphenolic pigment found in the cotton plant and in the small pigment glands in the seed. During processing some of the glands are ruptured and the gossypol released. It may become bound with various compounds of the seed. The remaining gossypol termed "free" gossypol is harmful when fed at high levels. Research has not definitely determined if both bound and free gossypol have an effect in the animal.

It has been know for many years that gossypol was harmful to monogastrics such as chickens, swine, and young ruminants. Until recently mature ruminants were thought not to be affected by gossypol. However, in 1975, while working with a 700 cow dairy herd in Alabama, gossypol toxicity developed when large amounts of cottonseed meal was fed as the single source of protein to achieve high levels of milk production. Approximately 25 head of mature cows exhibited classical gossypol toxicity symptoms and died. These symptoms were depression, loss of appetite, anorexia, labored breathing and red blood cell fragility. In a later controlled study at Auburn University, these same symptoms were demonstrated when cows were consuming an average of 24 grams of free gossypol per cow per day. Also, the livers of cows at the end of the study contained free, bound and total gossypol levels in relationship to the level of intake.  The 24 grams per cow per day calculate out to approximately 18 mg of gossypol/lb of body wt/day or approximately 0.1 percent gossypol in the total dry matter.

How to Determine Safe Levels to Feed

TABLE 1

Gossypol Levels in Selected Cottonseed Products (Martin)
Product	% Total Gossypol	% Free Gossypol
Whole Cottonseed	--	0.47-0.63
Delinted Whole Cottonseed	--	0.47-0.53
Cottonseed Meal Screwpress	1.02	0.02-0.05
Prepress Solvent Extracted	1.13	0.02-0.07
Direct Solvent Extracted	1.04	0.1-0.5
Cottonseed Hulls	--	0.06
Feedstuffs, August, 1990.

 

Table 1, adapted from an article in Feestuffs, August 6, 1990, shows the ranges in gossypol content of various cottonseed products.

Using the information in Table 1 and the limited research that indicate that 0.1% or 18mg per pound of live animal weight is the maximum that can be fed, one can begin to estimate an amount that might be fed safely. Since the 0.1% caused deaths certainly this amount should not be fed. Based on field experience, 6 pounds of whole cottonseed has been successfully fed for fairly long periods of time and up to 8 pounds have been fed for short periods without apparent harm. Using the information in Table 1 for whole cottonseed lets assume that there is 0.5% free gossypol present and 6 or 8 pounds are being fed. How much free gossypol are cows consuming?

The calculations are:

6 x 0.5 100

= 0.03 lbs of gossypol

 

Assume the cows are consuming 45 pounds of dry matter.
Then the ration contains .067% gossypol.

0.03 45 lbs. DM

X 100 = 0.067%

 

For a group consuming 8 pounds whole cottonseed the calculations are:

8 X 0.5 100

=

1.04 lbs. 45 lbs. DM

= 0.089% free gossypol

 

Another way of calculating this is to calculate the grams of gossypol intake. This is done by multiplying 454 grams x pounds of gossypol. For the above example, 6 pounds of whole cottonseed contains 0.03 pounds of gossypol or 13.62 grams (454x 0.03= 13.62) and 8 pounds yield 0.04 pounds or 18.16 grams (454 x 0.04= 18.16) of gossypol. Similar calculations can be made for various combinations of cottonseed products by calculating the amount of gossypol contributed by each source and adding the amount contributed by each source.

An example of this is illustrated as follows:

The dairymen is feeding 3 pounds of whole cottonseed and 6 pounds of direct solvent extracted meal that contains 0.3% free gossypol.

3 lbs X 0.5 100

= 0.015 lbs gossypol

6 lbs X 0.3 100

= 0.018 lbs gossypol

0.015 + 0.018= 0.03lbs

0.033 x 454 = 15 grams

Again based on the limited data we would expect the 15 grams of free gossypol to be an upper limit for safe feeding. This may not be a safe level for long term feeding during summer when respiratory stress is extremely high.

How to Feed Young Stock

Again, limited research indicates that young ruminants may safely be fed 5 to 10 mgs per pound of live weight of gossypol. Suggested upper limits for various size replacements are shown in Table 2 using 10mg/pound of live weight or 1 gram/100 pounds of body weight.

TABLE 2

Suggested Maximum Gossypol and Whole Cottonseed Levels for Replacement Dairy Heifers and Cows
Body Weight	Gossypol (grams)	Whole Cottonseed (lb)
300	3	1.30
500	5	2.20
700	7	3.10
900	9	4.00
1000	11	4.85
1200	13	5.70
1500	15	6.60

 

Fat Content

Whole cottonseed’s fat content (18%) also should limit its feeding to about 6.0 pounds per cow per day. Six pounds of whole cottonseed will yield approximately 1.0 pounds of fat which is about the maximum recommended from oilseeds. Higher levels of whole cottonseed can be fed but other sources of fat should be limited. Too much fat in the ruminant’s diet will decrease rumen fiber digestion and cause a laxative effect. As much as 12 pounds per dairy cow has been fed during periods of high milk production.

Aflatoxin

Aflatoxin can be a problem in feeding whole cottonseed. Plants under stress (drought, insects) can develop high levels of aflatoxin. Also cottonseed that have not been dried properly or handled improperly in storage may mold and contain aflatoxin. Every load of milk is tested for aflatoxin and must be below 0.5 ppb to be sold. The dairy cow is very efficient in converting aflatoxin in the plant to aflatoxin in the milk. To be sure that the milk is safe, the diet should be below 20 ppb of aflatoxin.

Whole cottonseed is an excellent feed and should be used extensively whenever practical. It is an excellent source of protein (20%) crude fiber (22%) and TDN (87%). Finally don't overfeed them because they are a good buy! Good things can be overdone!

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