ans 123 animal growth final examination june 13, 2007...

ANS 123

Animal Growth

Final Examination

June 13, 2007

I declare that I have read, understand and agree to abide by the Code of Academic Conduct of the University of California, Davis.

___________________KEY_____________________ Name / ID number

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June 13, 2007 Bonus questions:

1) How much does the Shrek baby weigh (lbs)? 2) Its residual feed intake is very negative; why?

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ANS 123 Animal Growth Name_____________________

June 13, 2007 Final exam Student ID __________________

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READ THESE INSTRUCTIONS! A. Please write your name at the top of each page, and on the Scantron sheet; also fill in the

bubbles on the Scantron form for your ID. B. Sections I (questions 1-75) and II (questions A1-A6) are mandatory for everybody; then

select EITHER section III (multiple choice, questions 76-100) OR section IV (short answer, questions B1-B4).

C. If you complete section III, fill in the bubble for Exam A; if you choose section IV, fill in Exam B.

D. Read all questions first, and read each question carefully. E. Each question has one best answer. F. Don’t cheat – it ruins my day. SECTION I. Multiple choice - mandatory (1 point each) 1) As animals grow, their surface area grows in direct proportion to body mass.

a) true b) false

2) In the allometric equation Y = aXb, values of b that are greater than 1 indicate a tissue that a) grows in proportion to twice the body weight b) grows more slowly than the whole body c) grows faster than the whole body d) grows in proportion to half the body weight e) grows in direct proportion to body weight.

3) An example of a tissue with the characteristics shown above is

a) bone b) skeletal muscle c) adipose tissue d) liver e) brain

4) The four main chemical components of the body, and their approximate concentrations in the normal adult are: a) water (90%), protein (5%), fat (3%), carbohydrate (2%) b) water (70%), protein (10%), fat (15%), carbohydrate (5%) c) water (40%), protein (20%), fat (30%), ash (10%) d) water (50%), protein (20%), fat (25%), ash (5%) e) none of the above



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5) At what time during pre-natal development does cell division switch from synchronous to asynchronous: a) 2 cells b) 3 cells c) 4 cells d) 8 cells e) 16 cells

6) The three layers of the inner cell mass of the blastocyst are:

a) endoderm, mesoderm, exoderm b) ectoderm, mesoderm, endoderm c) epiderm, metaderm, endoderm d) exoderm, metaderm, periderm e) none of the above

7) The following tissues arise from the middle cell layer in #6:

a) muscle, liver, bone b) bone, skin, adipose c) muscle, bone, adipose d) liver, skin, brain e) none of the above

8) Most prenatal weight gain occurs in the

a) first trimester b) second trimester c) third trimester d) growth is the same in all trimesters

9) Hyperplasia is a) an increase in cell size b) an increase in cell number c) a decrease in cell potency d) an increase in cell potency e) none of the above

10) Hormones that are produced in one tissue and act on a distant tissue are called

a) endocrine b) paracrine c) autocrine d) exocrine e) autophasic



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11) Hormones that are produced in one tissue and act in the same tissue are called a) endocrine b) paracrine c) autocrine d) a and b e) b and c

12) In muscle, IGF-I acts to a) inhibit protein degradation b) stimulate protein synthesis c) inhibit DNA synthesis d) a and b e) all of the above

13) Because growth hormone stimulates production of insulin-like growth factor I (IGF-I), the

concentrations of these two hormones in blood are always highly correlated. a) true b) false

14) Acromegaly is due to an excess of GH prior to growth plate closure.

a) true b) false

15) Insulin is an anabolic hormone.

a) true b) false

16) Baseline GH levels are always higher for males than females.

a) true b) false

17) The following is NOT true of insulin:

a) stimulates glucose uptake b) inhibits gluconeogenesis c) stimulates lipogenesis d) produced in liver e) is anabolic

18) Somatotropin secretion is affected:

a) positively by somatostatin b) positively by insulin-like growth factor I c) negatively by GRF d) in the posterior pituitary e) positively by low feed intake.



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19) The three types of bone are long, short and flat. a) true b) false

20) Flat bones are formed by intramembranous ossification within a cartilage model.

a) true b) false

21) Cartilage is used for:

a) the production of red blood cells b) the release of GH c) the depletion of bone d) shock absorption e) digestion

22) A chondrocyte is an immature cartilage cell

a) true b) false

23) Ossification is the mineralization of osteoid by deposition of hydroxyapatite crystals

a) true b) false

24) Growth plate closure occurs when it becomes ossified and calcified and is mediated by a

single, systemic event a) true b) false

25) Extracellular calcium levels are regulated by calcitriol, calcitonin and calpastatin

a) true b) false

26) In mammals, skeletal muscle fiber formation is generally complete by the end of

a) the first trimester of pregnancy b) the second trimester of pregnancy c) the third trimester of pregnancy d) birth e) puberty

27) Fast twitch glycolytic fibers require increased numbers of mitochondria.

a) true b) false



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28) A motor unit is: a) a set of nerves innervating a single muscle fiber. b) a set of fibers innervated by a single nerve. c) one nerve innervating one fiber. d) horsepower. e) none of the above.

29) Red muscle fibers have the following characteristics:

a) aerobic metabolism mainly b) anaerobic metabolism mainly` c) found in bird legs mainly d) found mainly in turkeys e) a + c

30) Which characteristics are found in slow twitch oxidative muscle fibers?

a) increase in mitochondria b) increase in vascularization c) small diameter d) small cell size e) all of the above

31) By birth only one nerve connects to each fiber, but each nerve contacts many fibers.

a) true b) false

32) Brown adipose cells contain unilocular lipid droplets.

a) true b) false

33) Brown adipose tissue’s primary function is _____.

a) energy storage b) cushioning c) insulation d) heat production e) all of the above

34) White adipose tissue’s primary function is _____.

a) energy storage b) cushioning c) insulation d) heat production e) all of the above



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35) In genetically obese animals, _________ plays a greater role. a) increased fat cell number b) increased fat cell size

36) In nutritionally obese animals, _________ plays a greater role.

a) increased fat cell number b) increased fat cell size

37) Intramuscular fat develops after all other adipose depots.

a) true b) false

38) The following is/are important adipogenic regulatory factor(s)

a) myogenin b) PPARγ c) adiporhelin d) a and b e) a and c

39) The following enzyme(s) is/are involved in mobilization of lipid from adipose tissue

a) lipoprotein lipase b) fatty acid synthetase c) hormone sensitive lipase d) acetyl-coA carboxylase e) none of the above

40) Obese subjects often have

a) larger adipocytes than normal b) two populations of adipocytes c) less intracellular fat d) a and b e) all of the above

41) The first nutritional factor limiting growth is

a) glucose b) energy c) fat d) carbohydrate e) protein

42) Feed conversion efficiency is the ratio of weight gain to feed intake

a) true b) false



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43) In the equation RE = a + b·ME, the coefficient a represents a) the gross efficiency of growth b) the maintenance energy requirement c) the net efficiency of growth d) 1/maintenance e) – fasting catabolism

44) In the equation RE = a + b·ME, the coefficient b represents

a) the gross efficiency of growth b) the maintenance energy requirement c) the net efficiency of growth d) 1/maintenance e) – fasting catabolism

45) Energetically (i.e., kJ RE/kJ ME), body protein gain is ______ than fat gain. [Hint: pay close attention to the units!] a) more efficient than b) less efficient than c) the same efficiency as

46) On a weight basis (i.e., kg gain/kg feed), lean gain is ______ fat gain. [Hint: pay close

attention to the units!] a) more efficient than b) less efficient than c) the same efficiency as

47) Whole-body glucose requirements (mg·kg-0.75·min-1) are __________ in ruminants as

compared to non-ruminants. a) higher b) lower c) similar

48) The primary site of gluconeogenesis is the kidney.

a) true b) false

49) Major gluconeogenic substrates for ruminants include

a) glucose b) amino acids c) propionic acid d) acetic acid e) b and c



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50) The major lipogenic substrate for non-ruminants is a) glucose b) acetate c) lactate d) glycerol e) amino acids

51) The major lipogenic substrate for ruminants is

a) glucose b) acetate c) lactate d) glycerol e) amino acids

52) Lysosomal protein degradation involves proteasomes and calpains.

a) true b) false

53) All of the following are essential amino acids except:

a) phenylalanine b) methionine c) threonine d) isoleucine e) glycine

54) The following is a major factor causing meat to be tougher:

a) decreased intramuscular fat b) increased activity of calpastatin c) decreased protein gain d) more rapid protein degradation e) decreased intermuscular fat

55) Men are generally taller than women, mainly because of

a) higher growth hormone levels b) faster growth throughout childhood c) a delayed growth spurt d) all of the above e) none of the above

56) The thermoneutral zone is the range of temperatures in which _____________.

a) animal performance is optimal b) maintenance energy requirements are minimal c) thermogenesis is increased d) a and b e) b and c



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57) This temperature range is ________________ in younger, as compared to older animals. a) wider and lower b) wider and higher c) narrower and lower d) narrower and higher e) none of the above

58) Which environmental variable has the greatest effect on animal growth?

a) precipitation b) humidity c) temperature d) day length e) altitude

59) Poor sanitation depresses animal growth only when clinical signs of infection are present.

a) true b) false

60) The following are common responses to infection: a) increased feed intake, increased body temperature, and decreased metabolic rate b) increased feed intake, increased body temperature, and increased metabolic rate c) decreased feed intake, increased body temperature, and increased metabolic rate d) decreased feed intake, decreased body temperature, and increased metabolic rate

61) Cytokines are hormones that a) are produced by the immune system b) act on the immune system c) are pro-inflammatory d) are anti-inflammatory e) all of the above

62) What type of cell is unique to the humoral immune response?

a) macrophage b) B-lymphocyte c) T-lymphocyte d) T-H1 cells e) Il-1 cells

63) All things being equal, animals eat mainly to

a) fill their stomachs b) meet their protein needs c) meet their energy needs d) have fun e) none of the above



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64) The ventromedial hypothalamus is also known as the a) satiety center b) appetite center c) feedback regulatory center d) melanocytic center e) YNP center

65) Leptin is produced in ________ and acts mainly on __________.

a) brain, adipose b) liver, adipose c) adipose, liver d) adipose, brain e) liver, the whole body

66) An obese mouse with normal blood leptin concentrations is likely a(n) _________ mouse.

a) ob/ob b) db/db c) Agouti d) a or c e) b or c

67) Genetic size-scaling theory states that biological rates are a function of mature body weight

raised to the ______ power a) 0.75 b) 0.73 c) 1.0 d) 0.25 e) 0.27

68) Genetic size-scaling theory states that time spans scale to the ______ power of mature body

weight a) 0.75 b) 0.73 c) 1.0 d) 0.25 e) 0.27

69) Genetic size-scaling theory states that accumulated amounts scale to the ______ exponent of

mature body weight a) 0.75 b) 0.73 c) 1.0 d) 0.25 e) 0.27



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70) If the genetic correlations between yearling weight (YW), marbling fat (MRB) and Warner-Bratzler shear force (WBS) are as follows, what would be the likely effects of selecting for increased marbling? [Note: WBS is a measure of meat toughness.]

YW MRB WBS

YW 0.40 -0.33 0.72 MRB 0.30 -0.31 WBS 0.50

a) lighter yearling weights and tougher meat b) heavier yearling weights and more tender meat c) increased marbling d) a and b e) b and c

71) In the example given above, __________ would show the most rapid response to selection.

a) yearling weight b) marbling score c) Warner-Bratzler shear force d) none of the above

72) Genetic selection for rapid lean tissue growth tends to produce animals with

a) increased rates of protein synthesis b) reduced rates of protein degradation c) unchanged rates of protein synthesis d) a and b e) b and c

73) Genetic selection for rapid lean tissue growth tends to produce animals that are

a) larger at maturity b) smaller at maturity c) unchanged mature size

74) Anabolic steroids used to promote growth

a) may be natural or synthetic b) increase rate of gain and feed efficiency c) result in fatter animals at the same weight d) a and b e) all of the above

75) Use of anabolic steroids in humans is always harmful and must be discouraged.

a) true b) false



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SECTION II. Short answer - mandatory A1. What is residual feed intake? Describe how it is measured and calculated, and why it is

important. [9 pts]

A2. Give two examples of anti-inflammatory cytokines, two examples of pro- inflammatory

cytokines and one example of a double action cytokine (pro and anti-inflammatory). [5 pts]



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A3. I have two dogs. Both weigh 20 kg, but one of them (Fluffy) has 15% fat and the other (Spike) has 30% fat in its body. Give 3 possible reasons for this difference in composition. [9 points]

A4. Describe the two-phase hypothesis of feed intake control. [8 points]



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A5. Choose a hormone that affects growth and body composition. Describe it, including general chemistry, sites of production and action, mechanisms of action and effects on target cells. [10 points]

A6. Compare and contrast two hormone classes that are used to stimulate growth. Include

performance, physiological and metabolic aspects. [9 points]



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SECTION III. Multiple choice - optional (1 point each; mark Scantron as Exam A)

76) The posterior pituitary controls the release of GH, FSH and LH. a) true b) false

77) IGF-I is synthesized by the liver and has a negative effect on the secretion of growth

hormone. a) true b) false

78) Growth hormone secretion is

a) sexually dimorphic b) stimulated by GRF c) inhibited by SRIF d) all of the above e) none of the above

79) Insulin affects growth hormone by

a) increasing the expression of the GH receptor in liver b) down-regulating GH secretion by the pituitary c) down-regulating IGF-I expression in tissues d) a and b e) all of the above

80) Which of the following are true effects of growth hormone?

a) increase in IGF-I secretion b) increase in muscle mass c) decrease in fat deposits d) all of the above e) none of the above

81) The periosteum and the epiphyseal growth plates grow faster when they are under greater

mechanical tension. a) true b) false

82) Flexible adipose tissue growth involves

a) new cells being recruited when adipose tissue exceeds some limits b) no new cells are ever recruited c) adipose cells become very flexible, they can bend in half d) muscle growth e) bone growth



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83) Compared to normal growth, compensatory growth is generally a) faster b) slower c) leaner d) a and c e) b and c

84) Compared to normal growth, compensatory growth is generally

a) less efficient b) more efficient c) the same efficiency

85) The following are possible explanations for compensatory growth:

a) increased food intake b) reduced maintenance requirement c) reduced fat content of the gain d) a and c e) all of the above

86) In ruminants, the gluconeogenic pathways are most active

a) just after the previous meal b) just before the next meal c) all day long d) mainly at night e) whenever the brain is concentrating hard, as on a midterm

87) In non-ruminants the gluconeogenic pathways are most active a) just after the previous meal b) just before the next meal c) all day long d) mainly at night e) whenever the brain is concentrating hard, as on a midterm

88) Which of the following are functions of amino acids?

a) precursors for protein synthesis b) precursors for gluconeogenesis c) substrates for energy production d) precursors for hormones e) all of the above

89) Bulls typically grow _______ than heifers

a) faster b) slower c) the same rate as



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90) At the same weight, males are generally _______ than females. a) leaner b) fatter c) the same composition as

91) As ambient temperature drops below the lower critical temperature, a) feed intake drops b) feed intake increases c) energy expenditure increases d) a and c e) b and c

92) As ambient temperature climbs above the upper critical temperature,

a) feed intake drops b) feed intake increases c) energy expenditure increases d) a and c e) b and c

93) Administration of leptin results in

a) increased feed intake and increased metabolic rate b) decreased feed intake and increased metabolic rate c) increased feed intake and decreased metabolic rate d) decreased feed intake and decreased metabolic rate e) none of the above

94) Adding MSG increases the palatability of feeds. a) true b) false

95) Neophobias and aversions are both psychogenic factors influence intake.

a) true b) false

96) All of the following control intake except:

a) leptin b) rate of passage in GI tract c) neuropeptide Y d) calcitonin e) amino acids



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97) ob/ob mice are obese due to a) impaired leptin synthesis b) lack of receptors for leptin c) low self esteem d) low GH e) none of the above

98) When manipulating growth, GH and ß-adrenergic agonists affect the growth of pigs and

ruminants but one is more effective in each specie so: a) GH is more effective in pigs b) GH is more effective in ruminants c) ß-agonists are more effective in both d) ß-agonists are more effective in ruminants e) a + d

99) Which of the following is NOT an effect of injecting growth hormone in pigs:

a) increased growth rate b) decreased body fat c) diabetes d) increased food intake e) increased plasma IGF-I

100) Administration of trenbolone acetate to a growing steer will increase its growth rate and

cause the appearance of secondary sexual characteristics. a) true b) false



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SECTION IV. Short answer – optional (mark Scantron as Exam B) B1. Diagram the somatotropic axis, showing the sites of secretion and main positive and

negative effects and feedback loops. [9 points]

B2. List three responses to cold that increase heat production, and three responses that reduce

heat loss. [6 points]

Increase heat production Reduce heat loss • Shivering thermogenesis • Cutaneous vasoconstriction • Increased feed intake • Altered posture (reduce surface area) • Increased voluntary activity • Horripilation



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B3. Describe the phenomenon of compensatory growth, including the conditions that cause it, what happens, and the main mechanisms underlying it. [6 points]

B4. How is the growth of mammalian males and females different? [4 points]

ans 123 animal growth final examination june 13, 2007...

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