Solution for Exam 3 Questions - Applied Animal Nutrition | ANSI 3653, Exams of Zoology

Download Solution for Exam 3 Questions - Applied Animal Nutrition | ANSI 3653 and more Exams Zoology in PDF only on Docsity! Name ______________________________________ Lab Sec. _________ AnSi 3653 Spring 2007 Exam 3 Beef Cow Nutrition 1. It is necessary for a producer of beef cattle to have a basic knowledge of varying forage species, their seasonal growing patterns and their nutrient composition in immature, mature and weathered, mature stages of growth. Given the nutrient composition of the native grass pasture in Oklahoma at three distinct periods of the year listed below, CIRCLE the correct quality classification and CIRCLE the dry matter intake expressed as a percentage of body weight guideline that has been established for the given quality for dry, gestating cows on a non-supplemented basis. A forage intake guideline table has been included on page two of this exam. (6 points) A. May, June DM CP TDN Ca Phos Carotene % % % % % mg/lb 45 10.5 52.3 0.42 0.09 84 EXCELLENT MEDIUM POOR 1.5% of body weight 2.0% of body weight 2.5% of body weight B. August, September DM CP TDN Ca Phos Carotene % % % % % mg/lb 60 7.2 45.6 0.33 0.06 27 EXCELLENT MEDIUM POOR 1.5% of body weight 2.0% of body weight 2.5% of body weight C. December, January DM CP TDN Ca Phos Carotene % % % % % mg/lb 93 2.5 37.5 0.32 0.03 0.5 EXCELLENT MEDIUM POOR 1.5% of body weight 2.0% of body weight 2.5% of body weight ____________________ 2. OSU has developed at scoring system to assess the nutritional status of beef cattle. What is the optimum body condition of cows in late gestation and at calving? (1 point) ____________________ 3. If a cow is a body score 4, how much weight must be gained for her to become a body score 5? (1 point) ____________________ 4. At what body condition score will a female become anestrus (will not exhibit estrus)? (1 point) 5. Body condition prior to calving is the best indicator of what reproductive trait? (2 points) 6. The production cycle of a beef cow can be divided into four unique periods. Which two periods are the most critical nutritionally? (2 points) A. _________________________ B. _______________________ ____________________ 7. Just as an automobile engine requires fuel to function, a beef animal requires energy for grazing, body maintenance, reproduction, lactation, etc. What is the primary source of energy for the grazing beef cow? (1 point) 8. Jim Henderson is trying to assess whether energy or protein is the primary limiting nutrient in his wintering feeding program. Mr. Henderson must consider two variables in determining whether energy or protein is the primary limiting nutrient for wintering beef cows grazing dormant winter forage. What are these two variables? (2 points) A. ______________________________________________ B. ______________________________________________ 11. A producer has a group of pregnant mature cows grazing abundant dormant native range grass during the winter, but due to the poor nutrient content of the forage numerous deficiencies are anticipated. He recently purchased a 20% Crude Protein range supplement with 6% Crude Fiber and 1.5% Crude Fat. The ingredients were listed as grain by-products, plant protein products, molasses, dicalcium phosphate, vegetable oil, salt and Vitamin A. Given the responses from various types of range supplements below, CIRCLE the response that this supplement should produce given the feeding situation. (2 points) RESPONSES a. Poor utilization of available nitrogen due to rapid breakdown of non-protein nitrogen in the rumen and a slow degradation of cellulose by the ruminal microorganisms resulting in reduced microbial protein synthesis and absorption of excessive ammonia nitrogen through the rumen wall into the bloodstream. b. Forage digestibility will decrease as a result of increase starch digestion in the rumen, causing a decrease in rumen pH and a decrease in the number of cellulose- digesting bacteria in the rumen (negative associative effect). c. Increased energy intake without detrimental effect on forage digestibility. d. Nitrogen requirement of ruminal microorganisms satisfied due to ruminal degradation of protein source; thus, increasing ruminal microorganism numbers which increases forage digestibility resulting in positive associative effect (increased forage intake). e. Ruminal bypass of available nitrogen resulting in limited utilization of nitrogen by ruminal microorganisms; thus, limited enhancement of forage digestibility. 12. A producer called to inquire about a new supplement that was being sold by one of the local feed stores. The supplement composition is presented on the feed tag below. Rancher’s Pride Molasses-Based Protein Supplement Crude Protein, % 25% (with no more than 12% crude protein equivalent from non protein nitrogen) Fat, % 5% Crude Fiber, % 2% Calcium, % 2% Phosphorus, % 1% Vitamin A, IU per lb. 10,000 IU a. Based upon the utilization of non-protein nitrogen in a molasses-based product, what is the % of usable protein in this supplement? (2 points) 13. Several different mineral mixtures are available at the local feed store: Supplement 1. 12% Calcium, 12% Phosphorus, 12% salt Supplement 2. 16% Calcium, 8% Phosphorus, 20% salt Supplement 3. 8% Calcium, 4% Phosphorus, 30% salt Since these supplements are being fed to supplement phosphorus and salt, the phosphorus content of the forage being consumed by the producer’s cattle is an important piece of information that is needed. Given the phosphorus content of the three forages below, match the proper phosphorus supplement with the appropriate forage; (3 points) % Phosphorus Proper Supplement Wheat pasture 0.40 % _______________ Dormant, native range grass 0.04 % _______________ Bermudagrass 0.20 % _______________ 14. A producer called recently concerned about nutritional status of his cows. His Angus crossbred cows appeared in acceptable body condition, but he was observing numerous females returning to estrus after they were apparently bred and he was very concerned about his calf crop percentage next year. He did state that the calves had a reddish coloration to their hair coat at birth and many of the cows had rusty colored patches of hair over their top and down their legs. Based upon these abnormal observations, what is apparently causing the problems in these cattle? (2 points) What can a producer do in order to specifically identify the cause of this problem? (2 points) 15. Since rumen microorganisms synthesize most of the required vitamins for ruminant animals, vitamin deficiencies are not usually noted in beef cattle. However, when young cattle are consuming dormant, weathered, mature range grass, it is possible for a Vitamin A deficiency to occur. What symptoms should be observed in young cattle with a Vitamin A deficiency? (2 points) 16. Winter stress is an important consideration in this state as well as many states to the north. Assuming that a 1300 lb. late gestating beef cow has a TDN requirement of 12.6 lbs. of TDN per day. The beef cow is suffering from winter stress. The outside temperature is 0o F with a wind speed of 20 mph, resulting in a wind chill index of - 20o F. If the cow’s critical body temperature is 30 o F, what would be her TDN requirement adjusted for the winter stress? (2 points) Calf Nutrition 17. The single most important nutritional requirement of the newborn calf is ______________________. (1 point) 18. The absorption of antibodies present in the first milk by newborn calves is very restrictive due to the closure of the intestinal wall to these large protein molecules. (3 points) Maximum absorption occurs prior to ________ hours of life. Absorption decreases to 50% of maximum by ________ hours of life. Absorption decreases to 0% by ________ hours of life. 19. If a newborn calf does not nurse and receive its necessary antibodies, name two alternatives for providing the necessary protection against disease? (2 points) a. _______________________________________________ b. _______________________________________________ Heifer Development 26. Name three factors important in determining the point at which a young heifer will reach puberty and initiate estrus activity? CIRCLE the one factor that appears to be the most important for expression of estrus activity? (4 points) a. ______________________________________ b. ______________________________________ c. ______________________________________ 27. This fall, Jamie Smalley weaned her Feb. and March, 2006 heifers. She weighed all of her heifer calves and weighed a few of the larger cows. The cows averaged 1300 lbs. in acceptable body condition. A. What is the minimum weight criterion as a percentage of mature body weight that is recommended for replacement females at first breeding? (1 point) 28. There are two common strategies used in the development of replacement females. System 1. Heifers are fed to gain a steady amount of daily gain (1-2 lbs. per day) throughout the developmental period. System 2. Heifers are fed to gain at a slower rate early in the developmental period and then at a faster rate during the last 60-90 days prior to breeding season. CIRCLE the system that results in an increased estrus activity as well as a higher first service conception rate. (2 points) 29. Cool season variety forages, such as wheat pasture, are excellent forages to use for the development of fall-calving replacement heifers from weaning to first breeding. TRUE or FALSE (2 points) 30. A group of medium framed heifer calves currently weigh 500 lbs. A replacement heifer ration contains 0.750 Mcal NE maintenance per lb. of feed and 0.45 Mcal NE gain per lb. of feed is being fed. Using Table 17. Net Energy Requirements for Growing/Finishing Beef Cattle, answer the following questions: a. What is the Net Energy maintenance requirement of the medium framed heifers? (1 point) b. What is the Net Energy gain requirement of the medium framed heifers in order to gain 2.0 lbs. per day? (1 point) c. How many pounds of the ration must be fed per head per day in order for the medium framed heifers to gain 2.0 lbs. per day? SHOW CALCULATIONS FOR FULL CREDIT (3 points) 31. What body condition score is recommended for heifers at calving? (1 point) Bull Nutrition 32. Many producers purchase 12-18 month old bulls in the spring of the year from performance bull testing centers and/or registered breeders to be used as breeding bulls. Many times these bulls go into a negative energy balance after purchasing and lose significant amounts of weight prior to and during the breeding season. Explain the proper management of “fleshy” bulls after purchasing and prior to the breeding season to insure proper breeding performance. (6 points) 33. A group of 800 large framed bull calves are being fed a performance bull ration that contains 0.80 Mcal NE maintenance per lb. of feed and 0.50 Mcal NE gain per lb. of feed to facilitate rapid weight gain. Assuming that the bulls are consuming 22 lbs. of feed per day, utilize Table 17. Net Energy Requirements to determine the following questions: a. What is the Net Energy maintenance requirement of the large framed bull calves? (1 point) b. How many Mcal. of Net Energy gain are consumed by the bull calves? (1 point) c. What is your best estimate of the average daily gain of the bull calves per day? SHOW CALCULATIONS FOR FULL CREDIT (3 points)