- - AGRICULTURE CORE CURRICULUM - - (CLF3000) Advanced Core Cluster: ANIMAL SCIENCE (CLF3150) Unit Title: NUTRITION AND FEEDS ____________________________________________________________________________ (CLF3158) Topic: COST EFFICIENCY Time: Year(s) OF PRODUCTION 4 hours 3 / 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson, the student will be able to: Learning Outcome #: (B-9) - Given specific data, calculate the rate of gain and cost of feed per pound of gain per day for three livestock species. (B-10) - Feed and maintain an animal through a full production cycle. Special Materials and Equipment: Feed samples and their current market price. References: Ensminger, M.E. (1983). THE STOCKMAN'S HANDBOOK (6th ed.). Evaluation: Completion of practice problems or a quiz by instructor. TOPIC PRESENTATION: COST EFFICIENCY OF PRODUCTION A. Definition of Rate of Gain 1. Rate of gain is a measurement of how much weight your stock is gaining over a specific time period. a. Rate of gain is a result of the animal's ability to convert feed into gain (muscle, fat, and bone). b. It also measures genetic potential when expressed as an Estimated Progeny Difference (EPD). B. Calculating Rate of Gain 1. Things to know: a. Rate of gain is calculated in pounds per day (lbs/day). b. First, you must determine a time period over which you will measure the pounds of feed consumed daily. For our example, let's use 30 days. c. Second, you need to measure the weight change during the time period. You need to weigh the animal(s) on day one and day 30. For this example, we will use a hog that gained 40 pounds over 30 days. 2. Calculations for Rate of Gain a. To calculate rate of gain, we want to determine how much weight was gained per day. For this example, we divide 40 pounds of weight gained in 30 days and we find that this hog gained about 1.3 pounds per day. b. Now try this example for a heifer calf. Over 45 days she gained 102 pounds. What is her rate of gain? (Answer: 2.27 pounds per day.) C. Calculating Feed Conversion Rate 1. Feed conversion rate measures the amount of feed the animal must eat to gain one pound of weight (abbreviated, lbs feed/lbs gain). Factors affecting feed conversion rate include: a. Species - animals that consume a high roughage diet must eat more feed to gain one pound because this feed is lower in energy. b. Type of feed - a highly palatable and highly digestible ration will give better feed conversion rates. c. Genetic potential - animals may be bred to have a better feed conversion rate than average. d. Fast growing animals take fewer days to reach weight, so less total feed will be used for maintenance. e. Efficiency of feed conversion depends on the feed. If one pound of corn is fed to a market hog and a steer, the pig is more efficient. If one pound of hay is fed, the steer wins. (Refer to question #5 on worksheet #5.) 2. Things to know when calculating feed conversion rates: a. First, measure how many pounds of feed are consumed over a time period. For example, let's say a hog eats 100 pounds of feed over 30 days. b. Now determine how many pounds of feed this animal consumed per day. Divide 100 pounds by 30 days and we find that it consumed about 3.3 pounds of feed per day. c. We now need the rate of gain per day for this animal. For this example, let's say the hog gained 45 pounds over the 30 day period. The rate of gain would be 1.5 pounds per day. d. It is important to remember that your calculation into rate of gain will be more reflective of the animal's true potential if it is calculated over at least a 30-45 day interval of time. 3. Calculations for Feed Conversion a. Using the above information, this hog gained 1.5 pounds per day and consumed 3.3 pounds of feed per day. b. How much feed does it take this animal to gain one pound of weight? (If your students have forgotten how to use the "units method" in formulas , refer to measurement in plant science in the Basic Core). 3.3 lbs feed per day X lbs feed per day ------------------------=---------------------- 1.5 lbs.gain per day 1 lbs gain per day (X = 2.2 lbs feed per pound of gain) c. Now try a practice problem Given a lamb that is being fed 6 pounds of feed per day. Over 30 days the lamb gained 20 pounds What is the feed conversion rate? (How much feed per pound of gain?) ANSWER: 8.96 pounds of feed per pound of gain D. Calculating Feed Costs 1. It is important to know the cost of feed consumed so you can estimate total production costs. 2. Calculations for feed costs. a. If you have formulated your own ration see CLF3154 "Developing Rations" for further discussion of costs. b. If you use a pre-mixed feed you will need to know the cost and weight per sack of feed or the cost per ton which must then be broken down to cost per pound. For example, you have a steer that eats alfalfa hay and a pre-mixed grain ration. Lets say the hay costs $110.00 per ton (2000 pounds) and the grain costs $8.50 per sack (75 pounds). This breaks down to $0.055 per pound for hay and $0.113 per pound for grain. c. To calculate cost of production, first determine how many pounds of each feed the animal is consuming and then multiply by the cost per pound. For example, lets say a steer eats 8 pounds of hay and 13 pounds of grain a day. Total feed costs would be 8 x .055 = $0.44 for hay and 13 x .113 = $1.47 for grain for a total cost of $1.91 per day. E. Rules of Thumb 1. Now that you've learned how to calculate rate of gain and feed con- version rates, here are some commonly used numbers to use in your calculations. Remember however these are estimates, to get a true picture, do your own calculations. 2. Feed conversion rates: ======================= Cattle 7 : 1 (7 pounds of feed for 1 pound of gain) Sheep 8 : 1 Swine 3 : 1 ======================== __________________________________________________________ ACTIVITY: 1. Ask the class which of the above animals could/would be least expensive to bring to slaughter weight. Discuss answers. (Note: see also "2b below). __________________________________________________________ a. Remember, your stock may do better than this depending on the environment and ration provided, as well as the individual's genetic potential. b. Cattle and sheep consume low quality, human-inedible feeds to a greater extent then swine or poultry. (Therefore, they do not "compete" with humans for food sources e.g., cereal grains.) __________________________________________________________ ACTIVITY: 1. Use supplemental worksheet #5 "Rate of Gain" to reinforce practice problems. 2. Use class examples from project animals to do feed conversion calculations and rate of gain practice problems. __________________________________________________________ INSTRUCTORS, PLEASE NOTE: Calculating a feed conversion ratio is indeed how feed conversion is expressed in this country. However, it is really the reciprocal of efficiency and tends to behave strangely when subjected to statistical analysis. Also, it is instructive to calculate feed efficiencies (or conversions) based on the following: 1. the entire life cycle of the animal, 2. a "human-edible" basis, 3. a dry weight basis, 4. a protein quality basis, and 5. numbers 1-4 all at the same time. SUPPLEMENTAL WORKSHEET #5 RATE OF GAIN NAME____________________________________ DATE____________________________________ PER.____________________________________ 1. Define rate of gain: 2. When would you want to use the rate of gain calculation? 3. Calculate the rate of gain for the following animals: a A hog gains 30 pounds in 45 days: b. A lamb gains 10 pounds in 30 days: c. A steer gains 53 pounds in 30 days: d. A heifer gains 96 pounds in 60 days: 4. Calculate feed conversion rates for the following animals: a. A steer consumes 400 pounds of feed in 30 days and gains 57 pounds. How much feed is he eating per pound of gain? b. A lamb consumes 150 pounds of feed in 30 days and gains 23 pounds. What is the feed conversion rate? c. A pig consumes 100 pounds of feed in 30 days and gains 38 pounds. What is the feed conversion rate? 5. Calculate the cost of feed per day for each of the following: a. A pig eats 100 pounds of feed and feed costs $7.75 per 50 pound sack. He eats this over 30 days. What is the cost per day of feed? b. The pig gains 35 pounds during this 30 days, what is the cost of the weight gain per day? (Hint: figure feed conversion) c. A steer eats 380 pounds of feed over 30 days. He ate 280 pounds of grain and 100 pounds of hay. What was the cost of his feed per day, if hay costs $100.00 per ton and grain costs $8.75 per (1) 80 pound sack? d. Over this period, the steer in problem #4c gained 53 pounds. What was the cost of his gain per day? 6. Which animal is more efficient at converting one pound of feed into one pound of gain? A steer or a pig? Why? 5/2/90sg #%&C