Supplementing Cattle on Cotton

With record-high feed and supplement costs across much of the beef industry, many producers look to whole cottonseed (WCS) to boost rations. This is a plentiful byproduct resource in many areas. Today, estimates show that more than half of the annual supply of WCS in the U.S. is consumed by dairy cattle.

The nutritional content of WCS averages 24% crude protein (CP) on a dry matter basis, 17% fat, 21% crude fiber, and 96% total digestible nutrients (TDN).

Four new studies, funded by Cotton Incorporated (CI), bring updated data for use by those considering feeding this crop byproduct in a variety of forms. Of special note is the impact on bull fertility today's WCS may or may not have when it comes to affecting bull fertility.

Susan Jaconis, agricultural research director at CI, said producers today use research to help them make informed decisions about what to feed cattle and how much of each ingredient should go into rations. "By collaborating with researchers, Cotton Incorporated has established the important role that whole cottonseed plays in cattle rations."

The four new studies, all published in Applied Animal Science, showed that fed at certain levels, whole cottonseed is safe and does not negatively affect bull fertility. Other noted points from the studies follow, with links to view the whole report.

1. WHOLE COTTONSEED'S IMPACT ON PERFORMANCE, SEMEN QUALITY

The effect of feeding WCS as a supplement was not found to have a meaningful impact on a beef bull's performance, semen quality and manganese superoxide dismutase concentrations.

The study noted that WCS supplementation at 0.7% of body weight for 60 days "may not negatively affect semen quality..." The research used 46 Angus bulls, 16 to 18 months old, housed at the University of Georgia's Tifton campus. Bulls were weighed and had blood and semen sampled on days 30 and 60. Bulls were randomly assigned one of three treatments: (1) 7 pounds per day of dried distillers grain; (2) 3.5 pounds per day of dried distillers grain plus 3.5 pounds per day WCS; or (3) 7 pounds per day of WCS. This study found that when fed in moderation, there was no effect on bull fertility from the WCS.

Beyond fertility, the study showed that bulls fed only the WCS had decreased average daily gains (ADG) compared with the other two groups. In addition, while there was not a final difference in scrotal circumference among the bulls, there was a time effect observed, but all recorded scrotal measurements were noted as "adequate to pass a breeding soundness exam at all time points."

This study's lead author was D.B. Davis, and it can be found here: https://www.appliedanimalscience.org/….

2. WHOLE COTTONSEED PLUS HARVEST/GIN RESIDUE FEED IMPACTS

Cow-calf operations in the South are familiar with not just the use of WCS as part of a feed ration, but also with the use of gin byproduct, and grazed harvest residue. A study out of the Department of Animal Sciences at Auburn University, led by M.K. Mullenix, considered the influence of WCS and cotton residue quality in feeding beef cattle.

Cotton residues, notes the report, are often used as roughage and are expanding as the industry evolves to more integrated crop-livestock systems and the availability of gin byproduct baling applications. It is also important to evaluate chemical residues to determine feeding safety.

Gin byproduct is most often used in beef cattle rations for animals with low energy requirements, such as non-lactating cows. Inclusion rates range from 5% to as much as 40%. A 1984 study, referred to in this report, showed that 90 cows mid-gestation fed 100% gin byproduct lost weight over a 90-day feeding period; but those on diets that also included sorghum silage (at 70%) maintained or gained weight. The study's authors noted that cows fed the 100% gin byproduct diet did not consume enough to meet daily TDN requirements, even though they exceeded their protein requirements by 38%.

Grazing cotton crop residue is often a source of winter feed. The nutrition levels are considered similar to those of gin byproduct, with the need to supplement for lactating beef cows. The estimate was that 2.47 acres of cotton stalk residue would support a nonlactating cow for 108 days. Those cows consuming hay over the grazing period gained 21.8 kg, compared to just 6.8 kg for those animals only grazing the crop residue. The cows maintained a Body Condition (BCS) of 5 or greater over the 84-day trial. As for chemical residues, including 2,4-D, glyphosate, tribufos, and thidiazuron, concentrations were well below threshold levels.

To read this report in its entirety, go here: https://www.appliedanimalscience.org/….

3. COTTON CROP RESIDUE TO EXTEND GRAZING PERIODS

The third study looked at a cotton residue grazing trial where producers extended grazing times and decreased feed costs for late-gestation beef cows over the winter. Essentially, this was using cotton residue for hay supplementation.

The study was led by D.B. Davis, at the University of Georgia. The study ran 30 days for three consecutive years and used 108 Angus crossbred cows. Cows were assigned to one of two treatments: (1) feeding on dormant bermudagrass pasture plus bermudagrass hay; or (2) feeding on cotton crop residue plus bermudagrass hay. The experiments started the first week of December each year. Each year, different amounts of cotton crop residue remained, explaining some of the statistical differences. Over that time period, edible residue remaining (including seed, link, boll/lead) ranged from 670.8 to 1,220.5 kilograms per 2.47 acres.

Across the studies, initial and final body weights for cows under both treatments were similar. There was no effect on average daily gain. The study noted that "although grazed residue has different nutrient composition compared with cotton gin by-product and whole cottonseed, this research demonstrates that it will serve as a replacement for hay."

One of the most notable points in the research goes to the cost of gain, and the cost per head per day for the different systems. In the bermudagrass pasture/bermudagrass hay system, cost per head per day averaged $1.79; in the cotton crop residue/bermudagrass hay system, cost per day averaged $0.63. This put cost of gain for the all-bermudagrass system at $2.37 per 2.2 pounds; and for the bermudagrass/cotton residue at $1.09 per 2.2 pounds.

To see this study in its entirety, go here: https://www.appliedanimalscience.org/….

4. COTTONSEED CHARACTERISTICS FOR PROTEIN, DIGESTIBILITY AND GOSSYPOL

This last study, with the lead author J.L. Jacobs and based out of the University of Georgia, considered the effect storage conditions have on protein and digestibility of WCS, as well as gossypol content and seed characteristics.

Seed used in the study came from 88 cotton breeding lines, obtained from a public cotton breeding program, and analyzed for CP, undergradable intake protein, degradable intake protein, gossypol concentrations, and seed size. Depending on moisture levels, cottonseed entering a storage period after ginning may undergo natural heating, which may damage nutrients. The study notes that recommendations and thresholds regarding gossypol were largely established in the late 1990s, and since that time, cottonseed composition has changed. In addition, seed size has decreased, which may alter nutrient composition in terms of livestock feed values.

The study used two samples of WCS showing different degrees of heat damage, sourced from South Georgia Cotton Gin in Hazelhurst. Three treatments were considered: (1) 0% heat-damaged WCS; (2) 50% heat-damaged WCS; and (3) 100% heat-damaged WCS. The chemical analysis, performed at the Agricultural and Environmental Services Laboratory at Athens, found the 0% heat-damaged treatment trended lower when compared to the 100% heat-damaged treatment for percentages of CP (19.32 versus 19.71); crude fiber (1.43 versus 1.11); fat (14.64 versus 16.48); calcium (1.42 versus 2.28); potassium (1.70 versus 1.84); magnesium (0.40 versus 0.34); sodium (0.17 versus 0.43); sulfur (0.44 versus 0.43); phosphorus (0.97 versus 1.11); chloride (0.38 versus 0.50); copper mg/kg (11.53 versus 13.03); manganese mg/kg (46.99 versus 57.98); and zinc mg/kg (41.62 versus 35.06).

To see this study in its entirety, go here: https://www.appliedanimalscience.org/….

Victoria Myers can be reached at vicki.myers@dtn.com

Follow her on Twitter @myersPF

(c) Copyright 2023 DTN, LLC. All rights reserved.