With corn prices high and getting higher, feedyard managers are looking to feed cattle to an acceptable quality end point the most efficient way possible. According to Dan Shike, University of Illinois animal scientist, initiating marbling early with corn, then finishing on co-products, may be something to consider.
At least that’s what research he and others conducted last year indicates. The research looked at the response of early-weaned Angus-Simmental heifer calves to a development program of high-corn creep feed, then a growing-finishing program of various levels of corn co-products.
The calves, part of a fall-calving herd, were weaned at around 77 days of age in November and early December. They spent the next 146 days on mostly dormant pasture with free-choice access to creep feed that consisted primarily of 44% cracked corn, 22% dry corn gluten pellets, 17.5% dried distillers grains (DGs) and 12% cottonseed.
Although consumption of the creep feed wasn’t recorded as part of this trial, Shike says past research under similar conditions showed calves ate 8-10 lbs./day.
The thought was to initiate marbling with corn at a young age (a time when consumption is less), then see how well the calves maintained that through a growing and finishing program of various levels of co-products.
“If you can initiate marbling at a young age with corn, calves are smaller and they eat much less,” Shike says. “So feeding them corn early saves on feed costs.”
Following the pasture phase, calves were ultrasound-measured to determine marbling and divided into four treatment groups:
• High starch, with 78% dry-rolled corn, 15% corn silage and no DGs (much like a traditional corn-based finishing ration);
• Intermediate starch of 49% corn, 17.5% dried DGs, 17.5% dry corn gluten pellets and 15% corn silage;
• Low starch, with only 9% corn, 40% dried DGs, 35% soybean hulls and 15% corn silage;
• A fourth group remained on pasture without supplement.
The calves stayed on these rations for 73 days. All the cattle then were put on the intermediate starch ration for the remainder of the 103-day finishing period.
The ultrasound data showed that the pasture-creep program initiated marbling in the calves. Ultrasound results also showed there was no difference in marbling among the cattle fed varying levels of corn during the 73-day experimental period. However, the pasture cattle weren’t able to keep up, as ultrasound data showed significantly lower marbling, Shike says.
“If you look at overall profitability, we actually lost a little money on the high-starch group, while the pastured cattle barely made any money. But the intermediate and low-starch groups showed a big swing,” Shike says. “There’s about a $45/head difference between the high-starch and intermediate-starch treatment groups, and low starch was comparable to intermediate.”
In fact, the heifers on the intermediate-starch ration were the most profitable because they were intermediate in feed costs and had the greatest percentage of carcasses grading average Choice or better.
The research found that heifers fed diets with greater percentages of co-products ate more feed, gained faster, increased yield grade, had fewer lightweight carcasses, greater carcass values, and similar marbling scores, which resulted in more profit, compared to heifers fed a high-grain diet.
Shike admits the system used in this trial results in a lot of days on feed and a lot of yardage. But, looking at the whole system, early weaning provides benefits on the cow side. Plus, when corn prices are high, the system can be cost-effective because it utilizes lower-priced co-products such as dried DGs, corn gluten feed and soy hulls without sacrificing marbling.
By removing the energy from corn, the remaining nutrients are concentrated three-fold in the resulting distillers grains (DGs) co-product. To assess the impact, University of Guelph researchers looked at the effect of various levels of DGs on nutrient excretion.
The researchers conducted two trials. In the first, groups of crossbred steer calves were fed diets containing 10% forage and 90% concentrates. The rations varied with either 17%, 33% or 50% dried DGs or modified wet DGs plus solubles, with the balance being whole corn. The control group received 90% whole corn. In the second trial, metabolic and digestibility measurements were collected on steers fed 0%, 17%, 33% and 50% dried DGs.
Digestibility decreased as the level of DGs increased. As a result, cattle fed dried DGs produced 14% to 27% more manure and 5% to 57% more urine than cattle fed whole corn.
Because dietary requirements for nitrogen, phosphorus and sulfur were met, excess minerals were excreted in the manure and urine.
“Compared to the whole-corn diet, feeding 17% dried DGs increased the daily excretion of nitrogen by 3%, phosphorus by 16% and sulfur by 52%,” the researchers say.
At 33% dried DGs, nitrogen excretion increased by 22%, phosphorus by 35% and sulfur by 100%; at 50% dried DGs, nitrogen excretion increased by 34%, phosphorus by 67% and sulfur by 183%.
Thus, manure management becomes more critical when cattle are fed DGs co-products. “Increased nutrient excretion in the urine and manure of cattle fed high levels of DGs may increase the nutrient content of manure and the land base required to spread it,” the researchers conclude.