In the last article, we broke down the cost per unit of protein and energy in 20% and 38% range cubes at current prices. This week we evaluate the money saved when purchasing feed on the cost per unit of protein or energy in order to meet a specific nutritional objective. The bottom-line point of this article is working through an example to determine the most cost-effective ration or supplement based on the feeding or supplementation objective.
The scenario and objective
We have 60 mature cows with an average weight of 1,300 pounds, due to calve in January, entering the last trimester of pregnancy. Cows are in a body condition score (BCS) of 5.5. We have ample standing forage in the form of native grass which forage analysis indicates is 5% crude protein (CP) and 55% total digestible nutrients (TDN). On grass of this type, cows should consume 1.9-2% of their body weight resulting in forage dry matter consumption of 25 lbs./day.
Knowing that reproductive efficiency is highly correlated to nutrition, our objective is for cows to maintain current weight and BCS until calving.
These cows will need 1.84 lbs. of CP and 13.3 lbs. of TDN per day over the next 100 days. If possible, we would like to maintain cows by utilizing the standing forage. Can this be done?
• 25 lbs. forage dry matter (DM) intake x 0.05 CP = 1.25 lbs./day CP intake.
• 1.84 lbs. CP required – 1.25 lbs. from the forage = a daily CP deficiency of 0.59 lbs./day.
• 25 lbs. forage DM intake x 0.55 TDN = 13.75 lbs./day TDN intake. There is no energy deficiency.
We have identified a supplemental need for protein. Research has consistently shown that protein supplementation is extremely effective for cattle grazing protein-deficient forage. In fact, energy supplementation will not be effective if dietary protein is deficient.
Now the question is which of the two protein supplements evaluated can most cost effectively meet our goal? The 20% CP range cubes at $350/ton or the 38% range cubes at $475/ton?
It would take 3 lbs./day of the 20% cubes to meet the CP requirement.
For example:
• 0.59 lb. CP deficiency/0.20 CP content = 3 lbs.
• We previously determined the cost per unit of CP in the 20% range cubes to be $0.875.Taking the 0.59 lb. CP deficiency x $0.875 = $0.52/day cost with 20% cubes to meet CP needs.
• This daily cost x 100 days of supplementation x 60 cows = an expense of $3,120.
It would take 1.58 lbs./day of the 38% cubes to meet the CP requirement.
For example:
• 0.59 CP deficiency/0.38 CP content = 1.58.
• We previously determined the cost per unit of CP in the 38% range cubes to be $0.625.
• 0.59 lb. CP deficiency x $0.625 = $0.37/day cost to supplement the cows with 38% cubes to meet their CP needs.
• This daily cost x 100 days of supplementation x 60 cows = an expense of $2,220.
Supplementing the 38% range cubes purchased at a cost of $475/ton instead of the 20% cubes at a lower price per ton resulted in a savings of approximately $900 to supplement the 60 cows for 100 days.
Unnecessary supplementation increases feed cost without real benefit. The goal of supplementation is to feed just enough of the right supplement to optimize the overall diet. Determining the most cost-effective means of supplementing cows requires the evaluation of feeds on a cost per unit of protein and energy provided. Can you afford not to?
Computer software, such as Oklahoma State University’s (OSU) Cowculator program, can better pinpoint an animal’s nutrient requirement at a specific time and in a specific stage of production. These and other useful tools can be found at beefextension.com.— Mark Z. Johnson, OSU Extension beef cattle breeding specialist
