34. Bovine Pregnancy Loss and Abortion

What is it called when there is death before the fetal period (day 42)

embryonic death

What is it called when there is death of the fetus prior to the age of viability which is 260 days?

abortion

What is it called when there is death of a fetus in utero that wouldve been viable in extrauterine? The fetus NEVER took a breath.

stillbirth

What is it called when there is death of a fetus or neonate during the birthing process?

intrapartum death

What are intrapartum deaths usually caused by?

dystocia or prolonged gestation

What is it called if there is death of a newborn that HAS taken a breath?

neonatal loss

What is a repeat breeder?

a cow that has failed to conceive after 3 services to a normal fertil bull or AI

When does the fetal period occur?

at attachment ( attachment is poorly defined)

What is the loss of a calf during pregnancy before it is born includinf everything from early embryo death to late term abortion?

fetal wastage

T/F The apparent rate of fetal wastage depends on when you diagnose it

True

When should you U/S the dam to see if fetal wastage is prenst?

26 days

When does pregnancy specific protein B arise?

30 days

When can you feel fetal wastage at?

32 days

Why do we see pregnancy loss with fetal wastage?

there is enhanced protein synthesis and cellular changes

What is defined as TRUE conception rate?

% of oocytes that are cleaved

What is the formula for apparent conception rate?

(# of females pregnant @ exam/ # of females inseminated) X 100

When do you preform the pregnancy exam for fetal wastage?

45 days

What is the apparent conception rate in beef cattle?

52%- 55%

What is the apparent conception rate in dairy cattle?

30-45%

When there is a pregnancy exam at 26 days, on U/S what is the pregnancy dx or the apparent conception rate in beef and dairy cattle?

beef cattle- 70%

dairy cattle- 40%

What is the expected pregnancy loss after 60 days in beef and dairy cattle?

- 2% in beef

- dairy- up to 10%

If there is pregnancy loss, what are FOUR fates of the non viable fetuses?

- abortion

- mummification

- maceration

- stillbirth

What are FOUR causes of abortion that lead to fetal wastage?

- infectious

- hormonal def

- nutritional

- toxic

T/F Fetal programming creates a negative energy balance which can lead to fetal wastage

True

What is the MAIN route of infection that leads to fetal wastage?

hematogenous infection

What happens in a hematogenous infection?

the infection crosses into the blood stream leading to placentitis

What are some examples of causes of Hematogenous infection? (6)

▪ Brucella

▪ Leptospirosis

▪ Listeria

▪ Neospora

▪ IBR, BVD

▪ Mycotic

What route of infection is common in equine but causes severe placentitis, infection of the fetus, and CTUP increased via bacterial or mycotic causes ?

Transcervical infection

What is an example of a toxin that causes non infectious fetal loss by inducing hypoxia and methemeglobin?

nitrate

What toxin is seen in various compounds in plants and examples are Coumenstans and Isoflavones?

Phytoestrogens

What are some plants that Coumestans is seen in?

alfalfa & clover

What are some plants that Isoflavones is seen in?

clover & soybeans

What mammalian estrogens does the Phytoestrogens mimic?

17𝛽-estradiol

What do phytoestrogens stimulate and what does this lead to?

stimulates the release of oxytocin which leads to the upregulation and release of PGF2a from the uterus

What kind of forage leads to a higher concentration on phytoestrogens?

fresh forage

What are the clinical signs of Phytoestrogen toxicity?

- Hormone level alteration

- Precocious mammary development

- Nymphomania

- Swollen external genitalia

- Estrus suppression

- Inhibition of ovulation

What is seen in sheep and cattle that leads to infertility and abnormal estrous cycle and leads to structural and functional changes to the cervix?

Clover disease

What is the toxic principle of Veratrum californicum?

Steroidal alkaloids

What is the MOA of Veratrum?

inhibit sonic hedgehog signaling pathway leading to cell differentiation, cell migration and facial symmetry

If there is Veratrum toxicity on day Day 13-14 gestation, what happens to the fetus?

cyclopic defect

f there is Veratrum toxicity on day Day 19 gestation, what happens to the fetus?

EED

When do limb defects, tracheal stenosis/agenesis occur with Veratrum toxicity?

day 28-33

When does cleft palate occur with veratrum toxicity?

Day 24-30

What can you do to help avoid the birth defects of veratrum?

avoid grazing in the first trimester

What gland does Veratrum act on that causes prolonged gestation?

pituitary gland

What is the most important livestock toxin in the western US?

Locoweed

What is the toxic principle of Locoweed?

Swainsonine

What is the MOA of locoweed?

interfers w/ glycoproteins which are important for reproductive horomones

What is the primary syndrome that preceded by repro signs?

locosim

What organs does locoweed effect? (4)

- pituitary gland

- ovary

- uterus

- fetus

What does locoweed do to females in the first 90 days?

- placental impairment

- abortion

- infertility

What are some other clinical signs of locoweed in females?

- increased interestrous peroud

- altered heat behavior

- lowered conception

What does locoweed cause in males?

- decreased libido

- poor semen quality

How do you treat/prevent locoweed toxicity?

deny access

What teratogenic qunolizidine alkaloid is seen west of the rocy mountains and causes problems in sheep and goats?

lupines

Where are the toxin concentrates in lupines due to them being more palatable?

seed pods

What disease does lupines cause in calves if consumed when the fetal limbs are develping between 40- 100 days of gestation?

crocked calf syndrome

What is the MOA of lupines?

alkaloid induced reduction in fetal movement

What are the clinical signs of lupines in cattle due to the MOA? (3)

▪ neuromuscular blocking effect

▪ skeletal contracture malformation

▪ cleft palate

How do you prevent lupine toxicity?

Stagger grazing or restrict access during susceptible

period

What is the toxic principle of Poison Hemlock?

Piperidine alkaloids → coniine

What does poison hemlock cause in cattle at 40-100days of gestation? (not a trick question)

crocked calf syndrome

What is the MOA of tobacco?

neuromuscular blocking agent

What is the toxic principle of tobacco?

pyridine alkaloids

What is the toxin of ponderosa pine?

ISOCUPRESSIC ACID (labdane resin acid)

What does iscopressic acid cause in cattle?

it is an abortofacient in cattle only that causes vasculitis

What is the most toxic part of the ponderosa pine?

needles

What is the MOA of ponderosa pines?

vasoconstriction of caruncular vascular bed which leads to reduction of blood flow leading to initiation of parurition

When does pondersoa pine cause abortions?

last trimester

What are the clinical signs of ponderosa pine? (8)

- Abortion

- Uterine hemorrhage

- Vulvar edema

- Udder development

- Incomplete cervical dilation

- Dystocia

- Weak calves

- Retained fetal membranes→ metritis→death

What feedstuff is nutritional deficencies commonly seen with?

stored hay

With nutritional problems, is abortions or stillbirths/weak calves more common?

stillbirths/weak calves

What are the THREE main nutritional deficiencies seen that causes weak calves?

- vitamin a

- low protein late in gestation

- selenium/ vitamin e

What hormone is a play when there is physical stress that can lead to fetal wastage?

cortisol

What is point in which an animal cannot dissipate enough heat to maintain normal body temperatures?

heat stress

What are FOUR environmental conditions that are contributing to heat stress?

▪ minimal cloud cover

▪ little to no air movement

▪ high relative humidity

▪ high overnight temperatures (>70° F)

What is an expression of apparent temperature and comfort of animals in it that is measured by a wet buld thermometer?

Temperature Humidity Index (THI)

T/F THI includes both temperature and humidity in determining the points at which heat stress may occur

true

What are the THI for the various species:

▪ Dairy cattle:

▪ Beef cattle

▪ Swine

▪ Poultry

▪ Dairy cattle: 72 oF

▪ Beef cattle : 72-75 oF

▪ Swine : 72-74 oF

▪ Poultry : 70-78 oF

cute lil chart for you

okay.... cool ig....

What is the stress level and clinical signs if the THI is < 72?

- none

- none

What is the stress level and clinical signs if the THI is 72-79?

- mild stress

• Cattle will seek shade to compensate

• ↑ in respiratory rate

• Vasodilation

• Minimal effect on production

What is the stress level and clinical signs if the THI is 80-89?

- moderate stress

• ↑ saliva production

• ↑ respiratory rate, ↑ H2O intake

• ↓ feed intake

• Effect on milk production & reproduction

What is the stress level and clinical signs if the THI is 90-98?

-severe stress

- • Panting

• Marked ↓ milk production & conception rates

What is the stress level and clinical signs if the THI is >98?

DANGER, DEATH

How do cattle respond to heat stress? (8)

▪ higher core body temperatures

▪ tachypnea

▪ tachycardia

▪ lower activity levels

▪ Increased water intake

▪ seek shade

▪ gather in cool area of the barn

▪ bunch

What are the metabolic consequences of heat stress?

▪ ↑respiratory rate

▪ ↑ increased blood flow to skin

▪ ↓ blood flow to core

▪ ↓ Dry matter intake

What does heat stress do to the overall conception rates and duration and intensity of estrus?

decreases

What TWO hormones are decreased with heat stress that can lead to fetal wastage?

▪ ↓ LH, E2

▪ reduced dominance of the selected follicle

T/F There is an increase in the CL size when they are heat stressed

False, decrease

If there is a decrease in the Follicular dominance, what does this lead to an increase chance of?

twinning

If there is a ↓ blood flow to uterus; ↑ uterine temperature, what does this inhibit?

inhibit embryonic development

T/F Heat stress leads to an increase in early embryonic death

True

What can heat stress induce causing premature luteolysis?

endometrial PG release