Growth and Development

Question 1

growth

Answer 1

increase in body weight until maturity is reached
increase in animal tissue: muscle, fat, and bone
measures of growth include: weight/unit time (WDT); height/unit time; average daily grain; days to 260 (swine); weaning weight; yearling weight

Question 2

true growth

Answer 2

only growth that involves an increase in structural tissues- excludes fat as storage tissue

Question 3

development

Answer 3

directive coordination of all diverse processes until maturity is reached
involves growth, cellular differentiation and changes in body shape
controlled by genetic make-up of the animal

Question 4

maturity

Answer 4

state of being fully grown or developed
in animal production, we often refer to sexual and compositional maturity

Question 5

physiological age

Answer 5

refers to stages (landmarks) of development as the animal grows from conception to maturity
-puberty

Question 6

chronological age

Answer 6

refers to the animal’s age in terms of units of time

Question 7

hyperplasia

Answer 7

an increase in the number of cells

Question 8

hypertrophy

Answer 8

as increase in cell size

Question 9

efficiency of growth

Answer 9

units of input per unit output
cattle: 7:1
sheep: 4-6:1
swine: 3:1/2:1
broilers: 2:1
fish: 1.1/1
in animal production, how much feed put in (lbs or kgs) per unit gain (lbs or kgs)

Question 10

normal growth curve

Answer 10

sigmoidal

Question 11

tissues with the greatest importance to life are first

Answer 11

A. highest priority: brain and heart
B. middle priority
C. low middle priority
D. lowest priority

Question 12

tissue development

Answer 12

nervous, bone, then muscle, then fat
wait to finish until fat has time to develop: rib and loin are last to develop

Question 13

order of fat deposition

Answer 13

perinephric/internal/ KPH (kidney, pelvic, and heart fat)/kidney-pelvic fat/leaf fat
-fat around the organs
intermuscular fat- seam fat, between large muscle groups
subcutaneous fat -external, back fat
intramuscular fat- marbling, flank streaking

Question 14

diversity of growth

Answer 14

heredity dependent
breeds develop differently, breed type influences mature size
phenotypic variation: outward visible expression influenced by heredity and environment

Question 15

measures of growth in livestock

Answer 15

beef cattle birth weight, weaning weight, yearling weight, feedlot ADG, mature weight
sheep birth weight, 60 day weight, 90 day weight, yearling weight, feedlot ADG, mature weight
swine birth weight, weaning weight, days to 260lbs
horses growth is generally measured in hands by a certain age
poultry days to slaughter weight

Question 16

genetic effects on growth and development

Answer 16

growth is a moderately to highly hereditable trait