Pregnancy Determination

Advantages Increase herd productivity Increase herd productivity Cull non-pregnant females Cull non-pregnant females Rebreed non-pregnant females Rebreed non-pregnant females Separation of twins vs. singles (ewes) Separation of twins vs. singles (ewes) **If done properly there are not many disadvantages

Pregnancy Determination A pregnancy test must be: Quick Quick Inexpensive Inexpensive Simple Simple Accurate Accurate Minimize animal handling and labor Minimize animal handling and labor Cannot cause abortion Cannot cause abortion

Determining age by uterine characteristics and fetal size Days of Gestation Identifying Characteristics Relative Fetal Size 30 *Uterus in approximate position of nonpregnant uterus *One uterine horn slightly enlarged and thinning uterine wall *Fetal membranes may be slipped through fingers from Small Marble (1/100 oz.) 45 *Uterine horn somewhat enlarged, thinner walled and prominent Small Egg (1/8-1/4 oz.) 60 *Uterine horn 2 1/2 to 3 1/2 in diameter *Uterine horn is fluid filled Mouse (1/4-1/2 oz.)

Days of Gestation Identifying Characteristics Relative Fetal Size 90 *Both uterine horns swollen (4-5” diameter) *Uterus begins descending into abdominal cavity *Uterine artery 1/8 to 3/16 ” in diameter *Cotyledons ¾ to 1” across, very soft Rat (3-6 oz.) 120 *Uterine horns continue descent into abdominal cavity *Uterine horns are 5 to 7” in diameter *Uterine artery ¼” diameter *Cotyledons 1 ½ “ in length (more distinct) Small Cat (1-2 lb.) 150 *Difficult to palpate fetus *Uterine horns are deep within body cavity *Uterine horns 6 to 8” in diameter *Uterine artery ¼ to 3/8” diameter *Cotyledons 2 to 2 ½ “ diameter Large Cat (4-6 lb.)

Days of Gestation Identifying Characteristics Relative Fetal Size 180 *Uterine horns are deep within the abdominal cavity and ascending phase of growth begins *Uterine artery 3/8 to ½ “ diameter *Cotyledons are more enlarged *From 6 months until calving the feet, legs, or head of the fetus can be easily palpated Small Dog (10-16 lb) After 7 months *Uterine artery ½ “ diameter at 210 days *Uterine artery ½ to 5/8” diameter at 240 days *Uterine artery ½ to ¾” diameter at 270 days *Continued increase in cotyledons after 7 months 210 (20-30 lb) 240 (40-60 lb) 270 ( lb) Increasing Fetal Size

Determining the Stage of Pregnancy Open cows: In females that are nonpregnant, the reproductive tract is usually located within the pelvic cavity; however, in older and large-frame cows the cervix and uterine horns may be distended over the pelvic brim into the body cavity. Determining Factors: 1.No fluids in uterus 2.No membranes present upon slippage 3.Thick uterine wall with a meaty texture 4.Uterine tone: Firm – at or near estrus Flaccid – between estrus periods

Determining Stage of Pregnancy Pregnancy Stage 1: Females in this stage vary from 40 days to 3 months of pregnancy. Cervix and uterine horns are in the pelvic cavity or perhaps moving over the pelvic brim in to the body cavity as stage 1 advances. Determining factors: 1.Fluids in uterus and somewhat enlarged 2.Presence of membranes upon slippage 3.Thin uterine walls 4.Buttons indistinct to the touch

Determining Stage of Pregnancy Pregnancy Stage 2: Females in this stage vary from 3 to 5 ½ months of pregnancy. Cervix is normally located on the pelvic brim with uterine horns distended into the body cavity out of the normal reach. Determining Factors: 1.Displacement of the uterus 2.Presence of buttons 3.Pulsation of middle uterine artery Fremitis – palpation of the uterine artery

Determining Stage of Pregnancy Pregnancy Stage 3: Females in this stage vary from 5 ½ months pregnant to term. Cervix is at or near the pelvic brim. Developing calf has achieved sufficient size to be reached. Palpation of the calf becomes progressively easier as Stage 3 advances. Determining factors: 1.Displacement of uterus 2.Palpation of large fetus 3.Presence of buttons