Section 4: Small Ruminant Flashcards
how large are small ruminant ovaries?
about 15mm long
where are small ruminant ovaries suspended?
brim of pelvis
how large are mature follicles in small ruminants?
10mm in diameter
how long is the small ruminant oviduct?
15-19 cm
tortuous
describe the small ruminant uterus
bicornuate
does the small ruminant uterus have an intercornual ligament?
yes
how many caruncles does the small ruminant uterus have?
80-100 caruncles
is an ewe lamb born with caruncles or do they develop later in life?
born with them
how many rings does the ewe cervix have?
4-6
what type of rings does the ewe cervix have?
interdigitating annular rings
what type of rings does the doe cervix have?
non-interdigitating annular rings
how many rings does the doe cervix have?
3-5
when does puberty occur in small ruminant females?
65% of mature weight
on average: 6-9 months
what type of estrous cycle do small ruminants have in the northern hemisphere?
seasonally polyestrous
short-day breeders
what is the estrous cycle length of an ewe?
16-17 days
what is the estrous cycle length of a doe?
18-21 days
how long do ewes show behavioral estrus?
24-36 hours
what are the signs of estrus in ewes?
subtle
standing for ram
hyperemic vulva?
mucus?
how long do does show behavioral estrus?
12-36 hours, some longer
what are the signs of estrus in does?
tail flagging
vocalization
frequent urination
standing for buck
when do ewes ovulate?
12 hours before the end of estrus
when do does ovulate?
12-36 hours after the start of estrus
what can affect ovulation?
number of ovulations
nutrition
breed
presence of male
exogenous GnRH
how long does ewe diestrus last?
14-15 days
how long does doe diestrus last?
17-20 days
what does diestrus end with?
PGF2alpha from uterus lysing corpus luteum
when does anestrus occur in small ruminants?
long days
what is anestrus?
not a stage of estrus cycle
when estrus cycle arrests
how long is the urethral process of the small ruminant male?
2-5 cm
what is most ventral in the small ruminant testicles?
tail of epididymis
how many degrees below body temperature are the testicles kept?
4-7 degrees C
what does scrotal circumference depend on?
breed
age
what accessory sex glands do small ruminants have?
ampullae
vesicular glands
bulbourethral gland
prostate: disseminate portion only
when do testicles descend in small ruminants?
80 days of gestation
in the fetus
if a male small ruminant is born with one or no testicles in the scrotum, will they descend later?
no
when do male small ruminants hit puberty?
50-60% of adult weight
typically 6-9 months but can have mature sperm in the epididymis as early as 3 months
when does the penis separate from the prepuce in small ruminants?
around 5 months old as testosterone increases
what is the precopulatory behavior of small ruminants?
sniffing
flehmen
nudging
mounting
urinating (buck only)
vocalizing
how fast is intromission/ejaculation in small ruminants?
instantaneous
what percentage of sperm penetrate the cervix in small ruminants?
5-10%
how long does small ruminant semen live?
24 hours
does sperm quality change in the non-breeding season?
yes- reduced in non-breeding season
_______________ is a natural behavior to establish rank/hierarchy
sodomy
also fighting
what is the dominance effect in small ruminant males?
dominant males within a herd/flock with physically interfere with mating by subordinate males
what is the audience effect of small ruminants?
subordinate males are psychologically inhibited from breeding when in sight of a dominant male
frequency of mounting and ejaculation is decreased
what is the gestation of small ruminants?
145-150 days
5 months
what is the lifespan of the unfertilized ova?
10-24 hours
are twins/triplets normal in small ruminants?
yes
when does maternal recognition of the pregnancy occur in small ruminants?
day 12
when does attachment of the fetus occur?
day 14-18
when does the fetus enter the uterus?
day 4
morula stage of embryo
do the embryos migrate to the other uterine horn?
if single embryo: no
twins: one embryo will migrate to other horn
what type of placenta do small ruminants have?
epitheliochorial cotyledonary
which small ruminant is dependent upon the corpus luteum throughout pregnancy?
doe
when is the ewe pregnancy not corpus luteum dependent?
after 50 days
uterus making enough progesterone to maintain pregnancy
_______ of fetal growth occurs in the last 2 months of gestation
85%
why is it important that so much fetal growth occurs in the last 2 months of gestation?
important to increase nutrition in the last trimester to support this growth and prevent pregnancy toxemia
what is the parturition cascade of the ewe?
fetal cortisol triggers production of 17-alpha hydroxylase by cotyledons
switch from progesterone to estrogen production by uterus
what does increased estrogen in parturition lead to?
synthesis of PGF2alpha
increased oxytocin receptors
release of relaxin
what is stage one of labor?
dilation of cervix
how long does stage one of labor last in the ewe?
2-6 hours
how long does stage one of labor last in the doe?
1-10 hours
how long does stage two of labor last in the ewe?
30 minutes to 2 hours
how long does stage two of labor last in the doe?
less than 1 hour of active labor, all kids delivered within 3 hours
what is normal delivery of small ruminants?
cranial
dorso-sacral
head resting on extended forelimbs
how long does stage three of labor last in ewes?
1-8 hours
how long does stage three of labor last in does?
within 12 hours
usually within 2 hours
when is it considered retained fetal membranes in small ruminants?
more than 12 hours
usually some pathologic reason for: mineral deficiency, abortion
what is a persistent frenulum?
failure of penis to separate from prepuce
how much ejaculate does a small ruminant produce?
0.5-2ml
what is the concentration of sperm per ml in a ram’s ejaculate?
1.5-3 billion
what is the concentration of sperm per ml in a buck’s ejaculate?
1.5-6 billion
what shape are the small ruminant caruncles?
concave
why is the ewe pregnancy not CL dependent after day 50?
uterus is making enough progesterone to maintain pregnancy
what do the fetal cotyledons produce in the parturition cascade?
17-alpha hydroxylase
what does the uterus switch in making during the parturition cascade?
progesterone to estrogen
what are the characteristic signs of stage 1 labor?
restlessness
nest building
pawing
moody
inappetence?