Quiz 5 from Quiz File Flashcards
During estrus females of some species will
a. have elevated levels of progesterone
b. become drowsy
c. stand to be mounted
d. exhibit tail flagging
C
D
Gestation
a. is from one ovulation to the next
b. is from conception until parturition
c. is 340 days in cattle and 260 in horses
d. is about 15% embryonic and 85% fetal stages
B
D
Bilateral cryptorchids
a. have no testicles
b. do not produce testosterone
c. have male characteristics and sex drive
d. are usually sterile
C
D
The cervix
a. is a passageway and storage site for sperm
b. produces gonadotropins
c. provides optimal temperature for spermatogenesis
d. provides a barrier to protect the uterus
A
D
The estrous cycle
a. is about 21 days in cows, mares, and sows
b. occurs when no estrogen is produced
c. includes a period of sexual receptivity called estrus
d. includes a follicular phase when estrogen increases
A
C
D
ovaries
a. produce GnRH and PGF2 alpha
b. produce estrogen
c. have follicles at different developmental stages
d. are fertilized by sperm to become zygotes
B
C
Puberty is defined as the age at which an animal is first capable of producing fertile gametes, which are sperm in males or ova in females.
true
The reactor penis muscle must relax to allow extension of the penis (sigmoid flexure) and delivery of sperm to the proper site.
true
The epididymis is a long continuous tube through which the ova pass by the action of cilia until reaching the site of hatching from the zona pelucida.
False
The ____________ of the testicle is the site where formation of spermatozoa occurs. This process is also called _____________, and the scrotum is a sac important for maintaining optimal temperature for the process.
Leydig cells
spermatogensis
____________________________ is released from the hypothalamus and acts on the anterior pituitary to stimulate release of LH and FSH. In males, LH stimulates production of testosterone from _______ cells of the testes. In females, FSH causes growth of follicles on the __________. Most follicles never ovulate, but undergo _____________________, or degeneration.
Gonadatropin Releasing Hormone
Leydig cells
ovaries
atresia
Large Graafian (antral) follicles produce high levels of __________ (hormone). This coincides with the phase of the estrous cycle known as estrus, when the female is receptive to the male. The hormone that causes female reproductive behavior also results in a surge of __________________ which causes rupture of the Graafian follicle and ovulation. The ruptured follicle initially becomes a corpus hemorrhagicum then develops into a _________________ (Two-words) which produces _________________ (hormone important for maintenance of pregnancy). If pregnancy is not recognized _____________ (a hormone produced by the uterus) cuses luteolysis
estradiol
leutenizing hormone
corpus luteum
progesterone
PgF2 alpha
The _______________ is a funnel shaped structure, which is the part of the oviduct that receives the ovum upon its release. Fertilization normally occurs in the oviduct, and the site of implantation and fetal development is the _________. The chronic and amniotic membranes develop _________, which provides nutrients, transports waste, synthesizes hormones, and provides protection for the developing fetus.
infundibulum
uterus
placenta
In animal breeding and genetics
a. epistasis means that some genes alter expression of other genes at a different location
b. milk production is a sex-limited trait, since the trait is only expressed in one gender
c. a yearling weight EPD should be used for comparison across different breeds
d. line breeding refers to breeding animals from different species, such as horses and donkeys
A
B
In cattle, polled (P) is a dominant allele ad horned (p) is recessive. In a population of 100 cattle, twenty-five of these cattle have horns. Based o the hardy-Weinberg law, one would estimate that:
a. frequency of the horned allele is .25
b. frequency of the polled allele is .5
c. half of the cattle would be Pp
d. 25 of these cattle would be PP
B
C
D
If a ram has an EPD of +5 for weaning weight, this indicates that the ram weighed 5 pounds more at weaning than the average of all sheep
false
The physical appearance of an animal, or __________ reflects an interaction of the genotype and the _____________
phenotype
environment
the abbreviation, EPD, refers to an ___________________, which is a useful selection tool
expected progeny difference
____________ is the fraction of the phenotypic differences between animals that is heritable, or can be passed on, from parents. Whereas carcass traits are highly heritable, _____________ is a trait with low h2
heritability
fertility
___________ refers to mating of animals that are closely related, which results in an increase in _____________ (heterozygosity or homozygosity) of both favorable and unfavorable gene pairs
inbreeding
homozygosity
Mating duroc males to unrelated duroc females would be considered _____________ , whereas mating the same duroc males to landrace females would be considered _________________, which refers to the superiority of these offspring over the average of the purebreds used in the breeding program
outcrossing/outbreeding
cross breeding
hybrid? vigor
Asume selected bulls have a weaning weight of 750 pounds compared with the herd average of 650 pounds. The heritability of weaning weight is .3 and the generation interval is 5 yrs. (1 per litter)
a. what is the selection differential for these bulls?
b. show how you would calculate the expected genetic change (progress) per year for this trait, assuming selected bulls were used in the breeding program.
c. what percentage of the genetic superiority of selected bulls would be transmitted to their calves
100 lbs
.3(100)/5
50%
