exam 3 Flashcards

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1
Q

define selection

A

most efficient mean to influence the rate of genetic change and improvement

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2
Q

what helps change the genotype

A

h^2, selection differential, population size, generation interval

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3
Q

what does h^2 do

A

the higher it is, the faster the rate of change

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4
Q

what is the equation for selection differential

A

mean of selected individual - the mean of the population

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5
Q

what is population size

A

greater size means greater superiority

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6
Q

what is the generation interval

A

the number of years for a population to turn over

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7
Q

define sources of information

A

selecting animals to change a population

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8
Q

what four things are sources of information

A

individual performance, pedigree, collateral relatives, progeny

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9
Q

individual performance is ____________

A

measurable

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10
Q

define pedigree

A

the performance of an individual’s ancestors

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11
Q

define collateral relatives

A

performance of half sibs and full sibs to look at sex-limited traits

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12
Q

define progeny

A

the best way to measure genetic worth

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13
Q

define accuracy

A

an estimate of how accurately the genotype of an individual for a certain trait can be predicted from phenotypic average of its relatives

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14
Q

define individual performance

A

a value highly related to h^2

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15
Q

what are the disadvantages of individual performance

A

sex-limited traits
traits requiring time
carcass traits
how h^2 traits

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16
Q

define estimated breeding value

A

a single trait

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17
Q

what is the equation for EBV

A

h^2(x-mean of x)/2

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18
Q

improvement is ____________

A

static

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19
Q

define accuracy of individual performance

A

based on one record

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20
Q

accuracy =

A

the sqrt of h^2

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21
Q

define pedigree

A

based on ancestor performance or the degree of a relationship

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22
Q

environmental correlation is between…

A

ancestors and individuals

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23
Q

what are the advantages of pedigrees

A

cheap
valuable for sex-limited traits
valuable for traits expressed later in life
low h^2 traits

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24
Q

how are traits measured accurately

A

by being measured in the same environment at the same age.

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25
Q

what are the disadvantages of a pedigree

A

inaccurate/no records
no comparative base for selection
can’t see if ancestry is good for a trait
mistakes can happen

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26
Q

what make up collateral damage? describe them

A

full siblings- same parents
half siblings- one common parent

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27
Q

what are the values of collateral damage

A

sex-limited traits
traits that require slaughter to measure
accuracy is lower

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28
Q

what factors affect the accuracy of sibling tests

A

h^2 of a trait
relationship of sibs
number of sibs tested

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29
Q

what makes up the correlation of the phenotype

A

environmental correlation
maternal environment

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30
Q

full sibs are _______ related
half sibs are ________ related

A

half
1/4

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31
Q

what are sibs helpful for

A

showing the accuracy of how h^2

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32
Q

define progeny testing

A

evaluation of the genetic makeup of an individual by phenotype of its progeny

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33
Q

what does progeny testing look at

A

qualitative and quantitative traits

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34
Q

what does progeny testing do

A

help determine the likelihood that an individual is a carrier of a detrimental allele

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35
Q

what factors affect the success of progeny

A

genetic makeup
number of offspring produced

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36
Q

define test mating

A

the number of offspring required to determine the likelihood an animal is not a carrier

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37
Q

what is the advantage and disadvantage of sirexrecessive

A

A- fewer matings required
D- finding recessive animals

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38
Q

what is the advantage and disadvantage of sire x heterozygote

A

A- known carrier
D- ID animals and more mating

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39
Q

what is the advantage and disadvantage of sire x daughter

A

A- easy to obtain
D- inbreeding depression, many progeny required

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40
Q

what is the BV of offspring compared to its parents

A

1/2

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41
Q

what does increased progeny mean

A

there is an increased accuracy

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42
Q

what does it mean if accuracy equals 1.22

A

it is 22% more accurate than normal

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43
Q

as h^2 increases…

A

more progeny are required to equal the accuracy of individual performance

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44
Q

what does net value depend on

A

several traits

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45
Q

what are the three basic methods of selection

A

tandem
independent culling method
selection index

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46
Q

define tandem

A

individually selecting one trait, then another

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47
Q

what are problems with tandem

A

genetic relationship of traits
more traits means slower progress
long time

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48
Q

define independent culling method

A

if an animal has below the minimum level in any trait is culled

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49
Q

what’s a problem with independent culling method

A

the animal may be outstanding in one trait, but below average in another trait, thus getting culled

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50
Q

define selection index

A

it places different degrees of emphasis on traits of interest

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51
Q

what does selection index determine?

A

the genetic worth of an animal

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52
Q

what does selection index do

A

gives an animal a total score by adding all the values

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53
Q

I=

A

b1x1 + b2x2 + bnxn

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54
Q

what does I, b, and x stand for in the equation

A

index value
weight vector
single item of phenotypic information

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55
Q

define BLUP

A

best linear of selection index
extension of selection index

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56
Q

where does performance data come from with BLUP

A

contemporary groups

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57
Q

what are contemporary groups

A

age
herd
etc

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58
Q

what are the three keys for selection? describe them

A
  1. genetic relationship among traits
    how strong a relationship is
  2. number of traits being selected for
    more traits means slower process
  3. h2 of traits
    correlated response (strength of movement of traits)
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59
Q

what is the most important trait in dairy cows

A

milk production

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60
Q

what are common dairy breeds

A

holstein, jersey, gurnsey, brown Swiss, Ayrshire, shorthorn

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61
Q

what traits are selected for in dairy cattle

A

milk production
fertility
% fat
temperament
calving ease

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62
Q

define total fat

A

increases with volume

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63
Q

define % fat

A

increases by unit

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64
Q

what are linear traits in dairy

A

stature
strength
body depth
dairy form
rump angle
foot angle

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65
Q

what is the h2 of milk production

A

0.35

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66
Q

what is the fat yield in cows

A

+0.75

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67
Q

what is % fat in cattle

A

-0.4

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68
Q

true or false: crossbreeding is constantly used in dairy cattle

A

false

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69
Q

which breed is best for the pound of milk produced

A

holstein

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70
Q

what cow has the best % fat

A

Jersey

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71
Q

what are the two sources of genetic improvement in dairy? describe them

A

sire- most genetic progress because they produce more
dam- little genetic process

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72
Q

what is dairy selection

A

the number of progeny vs. dam

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73
Q

what does AI allow for

A

large progeny

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74
Q

what is selection based on

A

closeness of females relatives and progeny testing of offspring

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75
Q

what does the DHIA do

A

create a system of records

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76
Q

what do DHIA records include

A

performance records of many sources of variation in performance and private cooperative operated through NCSU

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77
Q

what percentage of diary producers participate in DHIA

A

45%

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78
Q

what are sires selected on

A

PTA

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79
Q

what are the three keys in DHIA selection

A
  1. record systems are based on comparisons of contemporaries on a similar basis
    help select the best animal
  2. limited number of traits are selected for
  3. adoption of technology
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80
Q

what type of technology do dairy breeders use

A

AI
environmental control

81
Q

define environmental control. give examples.

A

modifying the environment for animals to produce more
health programs
nutrition
facilities
equipment

82
Q

define bST

A

a naturally occurring hormone in cows that regulate milk production

83
Q

what is IGF-1

A

insulin-like growth factor 1

84
Q

what does increased IGF-1 cause

A

increased milk

85
Q

what does bST cause

A

mastitis

86
Q

what does large scale use of information allow for

A

knowledge of differences in DNA sequencing in individual cattle

87
Q

describe cervical vertebral malfunction
year
bull
diagnosis
gene that is mutated

A

1999
Carlin M Ivanhoe Bell
genetic testing
SLC35A3

88
Q

describe bovine brachyspina
year
name
type of disease
symptoms

A

70s-80s
Sweet Haven Tradition
autosomal recessive
shortening of spine
reduced body weight
uneven teeth
malformed organs

89
Q

how many genes are deleted in bovine brachyspina

A

3.3 Kb

90
Q

describe the bovine leukocyte adhesion deficiency
year
bull
symptoms
affected gene

A

50s-60s
Osborndale Ivanhoe
fever
low appetite
chronic pneumonia
diarrhea
ulcers
stunted growth
impaired wound healing
gene affected is #383 on CD18 gene

91
Q

bovine leukocyte adhesion deficiency is an ____________ recessive and infects the _________ ___________

A

autosomal
soft tissue

92
Q

what amino acid is changed in BLAD

A

glycine replaces aspartic acid

93
Q

describer syndactlyl
phenotype
symptoms
mutation

A

autosomal al recessive with variable penetrance
digits are fused (commonly on front leg)
superior fat and milk
2 mutations on LRP4 gene

94
Q

describe bovine progressive degenerative myeloencephalophathy
autosome
affected genes

A

bos taurus autosome 4
affects 46 to 56 million base pairs
PNPLAS
CTTNBP2

95
Q

define synonymous

A

does not change amino acid being produced

96
Q

define non-synonymous

A

changes amino acids being coded for

97
Q

in beef selection, what is modified?

A

the animal, not the environment

98
Q

what are the 6 steps of beef infrastructure

A

purebred
cow/calf
stocker
feedlot
packer
consumer

99
Q

define purebred in the beef industry

A

provide genetics of cattle

100
Q

define cow/calf

A

produce one calf/cow/year
looking for calving ease and fertility traits

101
Q

define stocker

A

provide pasture for calves

102
Q

define feedlot

A

increase growth rate and IMF through feed

103
Q

define packer

A

slaughter and package meat

104
Q

define consumer

A

buy and consume products

105
Q

what are the three steps in beef selection

A
  1. producer goals and objectives
  2. different environments and available natural resources
  3. more traits of economic importance
106
Q

what are the goals/objectives of beef

A

calf production and increasing weight

107
Q

what does it mean if there are more traits being selected for in beef

A

the progress is slower

108
Q

define vertical integration

A

a main company

109
Q

true or false: the beef industry has vertical integration

A

false, it does NOT have vertical integration

110
Q

what is an example of vertical integration

A

tyson

111
Q

give examples of fertility traits

A

calving ease
heifer pregnancy
rebreeding rate
days open
daughter pregnancy rate

112
Q

give examples of growth traits

A

birth weight
weaning weight
yearling weight
ADG
feed efficiency

113
Q

give examples of carcass trait

A

IMF
fat thickness
ribeye area

114
Q

how does beef differ from dairy

A

performance records and technology usage

115
Q

what do beef cattle have in place of record systems

A

a sire summary for each breed

116
Q

what percentage of AI is used in beef

A

13%

117
Q

what can alter performance of beef cattle

A

GxE interactions

118
Q

why do beef have a slower adaption to technology

A

because herds are small and ranchers are part time

119
Q

what does crossbreeding take advantage of

A

heterosis

120
Q

what is the most useful tool for commercial beef producers

A

EPD

121
Q

what does EPD allow for

A

the best selection

122
Q

what does EPD do in rotational crossbreeding? in terminal?

A

uniformity
divergence

123
Q

why is the Angus at 0?

A

because it is the base for beef cattle because the bloodline is seen in most breeds

124
Q

what helps determine against deleterious recessive allele

A

genetic testing

125
Q

describe curly calf syndrome
year
breed
genotype
symptoms

A

1680
Angus
recessive
curved spine
extended and contracted limbs

126
Q

describe developmental duplication

A

the latest genetic disorder in Australia where calves are born with extra limbs

127
Q

define genetic testing

A

used to test for carriers of a trait

128
Q

what is MAS

A

marker assisted selection

129
Q

what are the 3 good points of beef selection? describe them

A
  1. economic traits have hight H2 and are not sex limited
    easier to select and offspring look like parents
  2. traits are easy to measure
  3. consolidation of packing industry
    cattle must be a particular weight and changes should be consistent
130
Q

what are the five keys to success for beef selection? describe them

A
  1. value of performance records and EBVs
    allows faster genetic increasing
  2. recognition and identification of breeds that excel in certain characteristics
    no one breed can be the best or perfectly fitted to the environment
  3. selection
    avoid fads
    determine herd objectives
    based on performance
  4. adjusted weaning weight
    possible sources of variation
    cow/calf
    age of calf
    breed
    age of dam
    sex of calf
  5. MPPA
    accounts for cows with different records
131
Q

define genetic standpoint

A

adjusted weights eliminate some variation

132
Q

what is the equation for genetic standpoint

A

(actual wt-birth wt)/age (x+birth wt)

133
Q

define repeatability

A

estimates probability of repeating

134
Q

what is the h2 of weaning wt? r?

A

moderate
0.4

135
Q

what does each portion stand for in HA+NR/H(n-1)r(CA-HA)

A

N- number of records/individuals
R- repeatability estimate for one record
HA- herd average
CA- cow average

136
Q

what are the best animals

A

ones with the highest number

137
Q

what are the three genres for sheep in the US

A

purebred
commercial
dairy

138
Q

describe purebred sheep

A

seed stock for commercial producers
show sheep or club lambs

139
Q

describe commercial sheep

A

used for meat (majority of income)
and wool, which is a secondary income

140
Q

describe dairy sheep

A

for cheese production, growing in the Great Lake region

141
Q

what are the three traits for economic importance

A

meat production
wool production
milk

142
Q

describe meat production

A

the number of lambs born and weaned
growth rate

143
Q

describe wool produciton

A

fiber diameter
fleece weight

144
Q

describe milk production

A

production/lactation

145
Q

determine the h2 for:
1. growth traits
2. carcass traits
3. reproductive traits
4. fleece traits

A
  1. low-mod
  2. low-high
  3. very low
  4. mod-high
146
Q

define prolificacy

A

production

147
Q

dressing %=

A

dressing wt/live wt x 100

148
Q

how many sheep breeds are there worldwide? in the US?

A

over 425
about 47

149
Q

in sheep, when is crossbreeding used? inbreeding?

A

commercial production
purebreds and breeds with small numbers

150
Q

are sheep EPDs common?

A

no, they’re only used in a few breeds

151
Q

what does the national sheep improvement program do?

A

calculates cross-flock EPDs for sheep

152
Q

define the central ram test

A

measures moderate to high h2 in a young ram

153
Q

describe spider syndrome
lethality
breeds
genotype
cause

A

semi-lethal to lethal
suffolk, Hampshire, southdown, Oxford
recessive
fibroblast growth factor receptors

154
Q

what is scrapie

A

a CNS disease

155
Q

how often is scrapie seen

A

1/500 mature ewes

156
Q

what are the losses due to scrapie

A

$20-25 million lost per year

157
Q

what does spider syndrome cause

A

lost export opportunities
increased offal disposal cost
reduced productivity

158
Q

what are some symptoms of scrapie

A

scraping off wool and hair
itching and rubbing
wool pulling
bunny hopping of rear legs
high stepping gait of forelimbs

159
Q

how does one diagnose scrapie

A

in a dead animal, examine the brain and lymph nodes for abnormal prions
in a live animal, examine the third eyelid

160
Q

what is the treatment for scrapie

A

there is none

161
Q

what causes scrapie

A

prion protein

162
Q

what codons are tested for scrapie

A

136, 154, 171

163
Q

what are important traits for sheep

A

booroola and callipyge

164
Q

describe boorcola

A

discovered in merino in australia
increases ovulation rate
mapped to 6 chromosomes
higher liter size, but poor survival rate and growth

165
Q

describe callipyge

A

mapped to chromosome 18
high dressing percentage and larger loin eye
creates tough meat
polar over dominance
decreases fat measure
improved feed efficiency and dressing %

166
Q

why are horses the least studied livestock

A

recreational use
long GI
long gestation
age to puberty
offspring/yr
lack of accurate records

167
Q

what is the main problem for determining h2 in horses

A

variation

168
Q

what are examples of variation in horses

A

racing
surface
condition
age
level of training
nutrition

169
Q

what is the largest variation in horses

A

environment

170
Q

what is data bias

A

choosing and selecting animals that perform well without giving others a chance

171
Q

what are traits for economic importance in horses

A

fertility and performance

172
Q

what is live foal crop? its %?

A

the amount of foals that survive
50-70%

173
Q

horses have a ______ performance compared to other livestock

A

lower

174
Q

how long is a horses estrus

A

5-7 days

175
Q

what is the artificial birth date of horses

A

Jan 1st

176
Q

define hand mating and pasture mating

A

hand- selecting which individuals mate
pasture- letting animals mate freely

177
Q

what are some examples of performance in horses

A

stride length
frequency of stride
muscle fiber types (1 or 2)

178
Q

what is muscle fiber type one good for

A

endurance

179
Q

what are horse sales based on

A

pedigree

180
Q

what is used to measure h2 in horses

A

speed index
lifetime earnings
average earnings

181
Q

what is the h2 for performance in horses

A

moderate

182
Q

trotters are ________ and pacers are _________

A

dominant; recessive

183
Q

what is the h2 of trotters and pacers

A

low

184
Q

what are the divisions of cattle work? describe them

A
  1. ranch work
    working livestock and rough terrain
  2. roping
    close contact with animals and high agility
  3. cutting
    highly athletic and response to calf movement outside the herd
185
Q

define cow sense

A

horse’s interest in a cow

186
Q

what is the h2 of cow sense

A

very low

187
Q

define barrel racing

A

speed and agility

188
Q

what is the h2 of:
1. free jump
2. with rider
3. winner over course
4. style

A
  1. mod-low
  2. low
  3. low
  4. high
189
Q

why are colored breeds not purebred

A

they don’t breed true

190
Q

what are mating systems used in equine

A

line breeding
positive assertive mating
inbreeding
crossbreeding

191
Q

describe equine line breeding

A

common
concentrates one individuals genes

192
Q

describe equine positive assertive mating

A

breeding the best to the best

193
Q

describe equine inbreeding

A

rare
used for creating new breeds or increasing small herds

194
Q

describe equine crossbreeding

A

used somewhat for breed development

195
Q

describe CID (combined immunodeficiency)

A

DNA PKCS
Arabian horses
recessive
affects immune system

196
Q

describe bleeders

A

exercised induced pulmonary hemorrhage
blood vessels burst in lungs due to respiratory infection
pounding hooves cause trauma in the lungs
adversely affect performance
recessive
causes diuretic

197
Q

describe wobblers syndrome

A

cervical vertebrae malformation
5, 6, and 7
ataxia
recessive
in TB and QH

198
Q

describe HYPP

A

a line of QH from Impressive
defective sodium voltage gate ion in muscle cells cause high K in the blood
dominant