Animal Science 144 Beef Cattle and Sheep Production. Fall Final examination. December 12, 2000

Transcription

1 Animal Science 144 Beef Cattle and Sheep Production Fall 2000 Final examination Please read and follow instructions carefully. 1/ Print your name (last, first) at the top of each page and sign the cover sheet. 2/ Write only in the space provided; this should keep the answers short and sweet. 3/ For multiple-choice questions, circle the letter for the one correct answer. 4/ There are 25 questions and 100 points. 5/ This is a closed-book examination. Look upon this as an opportunity to express your own unique individuality and creativity! In signing I affirm that I have not violated the Standard on Conduct of the University of California, Davis. Signature

2 1. (3 pts) Define three objectives that can be addressed when developing a grazing management plan. 2. (6 pts) Briefly define: (a) Stocking density (b) Stocking rate (c) Carrying capacity (d) Grazing pressure (e) Grazing period (f) Rest period 1

3 3. (1 pt) The average feed intake of a grazing ruminant is % of their body weight. 4. (5 pts) Answer True or False; if false explain why (a) The lower the stocking rate the lower the individual animal performance. (b) An uneven distribution of the animals in the pasture will increase problems with under and overgrazing. (c) Ideally, in large pastures water should be located in the center of the pasture in order to increase forage utilization. (d) Rangeland productivity is generally higher than that of cultivated pastures due to the higher level of inputs. (e) The decrease in quality observed in mature plants is explained by a decrease in its fiber content. 5. (8 pts) Name four factors affecting pasture growth and explain briefly. 2

4 Livestock Production (lb/animal or lb/acre) A B Grazing Intensity (stocking rate) 6. (6 pts) Two different curves are shown above: one corresponds to the ADG expressed as lb/animal, while the other corresponds to total lb/acre. Decide which corresponds to A and which one to B, and explain the reasons for your choice. 7. (6 pts) Define the concept of genotypic correlation and explain why is important to be considered when developing a breeding program. Give two examples, indicating the direction (sign) of the correlation. 3

5 8. (6 pts) Commercial strategic alliances between segments of the animal industry have been for many years very common in the poultry and pig industries. However, similar marketing and producing alliances are just appearing in the beef industry. Mention why this type of alliance can be beneficial for the beef industry. 9. (4 pts) Calculate break-even selling and buying prices (to the nearest $0.01) for the following stocker operations; show your calculations: Selling B. E. Buying B. E. Purchase wt, lbs Purchase price, $/lb 0.80 Cost of gain, $/lb Selling wt, lbs Selling price, $/lb

6 10. (5 pts) Label the main elements of this figure: Critical period days 11. (5 pts) For the following statements circle the correct answer in parentheses: (a) Cattle generally reach puberty at the age of (8-12 months, months). (b) The onset of puberty is more closely related to the (age, weight) of the animal. \ (c) In order to maximize rebreeding odds the ideal body condition score at calving is (4, 6). (d) Flushing is a short-term feeding strategy used prior and during (breeding, lactation) in order to improve fertility, (e) The highest nutritional demands of a cow are during (the last trimester of gestation, lactation). 12. (3 pts) Outline three differences between heifers and steers placed in a feedlot. 5

7 13. (5 pts) Answer True or False; if false explain why: (a) Performance is highly predictable from feed intake. (b) The higher the ratio of fat/lean in the gain the higher the efficiency of gain. (c) Cattle should be processed immediately after arriving at the feedlot. (d) Two to three days after vaccination occurs cattle decrease consumption due to an increase in body temperature. (e) The Feed Mill is the heart of the feedlot. 14. (5 pts) The average shrink loss for cattle being transported is % (urine and fecal losses only). Mention four factors affecting the degree of shrink. 6

8 15. (6 pts) After arriving at the feedlot animals are processed. Explain the different tasks that take place during processing. 16. (8 pts) Suppose that you are a feedlot consultant and you are asked to build a new feedlot. Describe and explain the several factors you need to consider regarding feedlot design (shade, pen size, feed bunks space, drinkers, pen direction, etc.). 7

9 17. (3 pts) Define accelerated lambing and list two ways it can be accomplished. 18. (3 pts) List the advantages of breeding ewe lambs. 19. (3 pts) List three factors that affect the ram to ewe ratio. 20. (1 pt) Wool that averages 21 micron would be classified as. 21. (1 pt) As the average micron increases the staple length will normally (increase, decrease). 22. (1 pt) For every 100 pounds of sheep milk approximately pounds of cheese can be produced. 23. (2 pts) Name two dairy breeds of sheep. 24. (2 pts) List the two hormones most frequently use to control the estrous cycle when artificially inseminating ewes. 25. (2 pts) Ewes are artificially inseminated between and hours after sponge (pessary) removal. 8