ANSC 3040 Final Review Questions with
Complete Answers 2026-2027 Updated.
Largest cost in Dairy Heifer Production? - Answer Nutrition/Feeding
2nd Largest Cost in Dairy Heifer Production? - Answer Replacement Heifers
When is Timed AI good? - Answer When estrous detection is less than 70% because timed AI
does not require ED
When do we want puberty in dairy heifers? - Answer 9-10 months of age/260-280 kg, feeding
and body weight are important factors for onset of puberty
When do we want 1st AI? - Answer 3rd estrous
When do we want pregnancy? - Answer 13-15 months (350-380 kg)
When do we want calving? - Answer 22-24 months (600-640 kg pre calving weight)
What data should be monitored? - Answer BCS, weight, activity level
How should we collect data? - Answer either snapshot method where measure groups at
different stages (less accurate) or longitudinal where measure group of heifers every day
(accurate)
Which is worse over-feeding or under-feeding before puberty? - Answer Both are bad,
overfeeding results in poor performance and underfeeding results in delayed puberty/anestrous
Optimal ED rate? - Answer more than 70%
Goal of Beef Cattle Production - Answer Maximize quality and quantity of calves
What are the early embryonic development steps that are conserved? - Answer 1. Ootid 2.
syngamy -> zygote 3. early blastocyst (2, 4, 8 cell) 4. Morula (can't cells anymore) 5. ICM and
trophectoderm differentiation 6. Hatching 7. Hatched
, What happens at the early blastocyst stage? - Answer Activation of embryonic genome and
regression of maternal genome (8 or 16 cell in cows, 4 cell in humans and pigs, 2 cell in mice)
How does an embryo hatch? - Answer enzymes from inside blastocyst are activated to
degrade, cell grows quickly, fluid accumulates inside which increases pressure and eventually
zona pellucida breaks
True or False preimplantation occurs in all species? - Answer False: not in humans, primates,
rodents
What occurs during preimplantation? - Answer conceptus elongates rapidly, becoming a
filament (except not in mares; it remains spherical)
What's the difference between hemotroph and histotroph? - Answer histotroph supplies
nutrients to embryo prior to implantation in uterus (uterine milk)
hemotroph supplies nutrients to embryo after implantation through blood supply
Maternal recognition of pregnancy in cows... - Answer ... is known by secretion of INFT
(interferon tal) which blocks oxytocin receptors preventing PGF2a from being secreted and
causing luteolysis
Maternal recognition of pregnancy in sows... - Answer ... is known by estrogen rerouting
PGF2a into the lumen for degradation instead of to its receptors
it also requires 2 pregnancies per horn for this to work
Maternal recognition of pregnancy in mares... - Answer ...is recognized by the movement of
the embryo around the uterus. The spherical embryo is covered in a glycoprotein "shell" and
secretes prostaglandins to induce myometrial contractions for 7 days until the conceptus fixes
into the uterus
Maternal recognition in bitches and queens... - Answer ... is not required because of their
anestrus periods
What are the phases of the embryonic development period? - Answer 1. morulation 2.
blastulation(totipotent to pluripotent, formation of blastocyst) 3. gastrulation( mesoderm,
ectoderm and endoderm/hypoblast) 4. organogenesis (from neural tube)
What are the phases of the fetal period? - Answer 1. growth 2. maturation 3. remodelling of
organs 4. parturition
Complete Answers 2026-2027 Updated.
Largest cost in Dairy Heifer Production? - Answer Nutrition/Feeding
2nd Largest Cost in Dairy Heifer Production? - Answer Replacement Heifers
When is Timed AI good? - Answer When estrous detection is less than 70% because timed AI
does not require ED
When do we want puberty in dairy heifers? - Answer 9-10 months of age/260-280 kg, feeding
and body weight are important factors for onset of puberty
When do we want 1st AI? - Answer 3rd estrous
When do we want pregnancy? - Answer 13-15 months (350-380 kg)
When do we want calving? - Answer 22-24 months (600-640 kg pre calving weight)
What data should be monitored? - Answer BCS, weight, activity level
How should we collect data? - Answer either snapshot method where measure groups at
different stages (less accurate) or longitudinal where measure group of heifers every day
(accurate)
Which is worse over-feeding or under-feeding before puberty? - Answer Both are bad,
overfeeding results in poor performance and underfeeding results in delayed puberty/anestrous
Optimal ED rate? - Answer more than 70%
Goal of Beef Cattle Production - Answer Maximize quality and quantity of calves
What are the early embryonic development steps that are conserved? - Answer 1. Ootid 2.
syngamy -> zygote 3. early blastocyst (2, 4, 8 cell) 4. Morula (can't cells anymore) 5. ICM and
trophectoderm differentiation 6. Hatching 7. Hatched
, What happens at the early blastocyst stage? - Answer Activation of embryonic genome and
regression of maternal genome (8 or 16 cell in cows, 4 cell in humans and pigs, 2 cell in mice)
How does an embryo hatch? - Answer enzymes from inside blastocyst are activated to
degrade, cell grows quickly, fluid accumulates inside which increases pressure and eventually
zona pellucida breaks
True or False preimplantation occurs in all species? - Answer False: not in humans, primates,
rodents
What occurs during preimplantation? - Answer conceptus elongates rapidly, becoming a
filament (except not in mares; it remains spherical)
What's the difference between hemotroph and histotroph? - Answer histotroph supplies
nutrients to embryo prior to implantation in uterus (uterine milk)
hemotroph supplies nutrients to embryo after implantation through blood supply
Maternal recognition of pregnancy in cows... - Answer ... is known by secretion of INFT
(interferon tal) which blocks oxytocin receptors preventing PGF2a from being secreted and
causing luteolysis
Maternal recognition of pregnancy in sows... - Answer ... is known by estrogen rerouting
PGF2a into the lumen for degradation instead of to its receptors
it also requires 2 pregnancies per horn for this to work
Maternal recognition of pregnancy in mares... - Answer ...is recognized by the movement of
the embryo around the uterus. The spherical embryo is covered in a glycoprotein "shell" and
secretes prostaglandins to induce myometrial contractions for 7 days until the conceptus fixes
into the uterus
Maternal recognition in bitches and queens... - Answer ... is not required because of their
anestrus periods
What are the phases of the embryonic development period? - Answer 1. morulation 2.
blastulation(totipotent to pluripotent, formation of blastocyst) 3. gastrulation( mesoderm,
ectoderm and endoderm/hypoblast) 4. organogenesis (from neural tube)
What are the phases of the fetal period? - Answer 1. growth 2. maturation 3. remodelling of
organs 4. parturition
