LA THERIO - Beef Cattle Flashcards
What are the most common causes of removal/culling of bulls from reproduction?
Abnormal sperm morphology (52%)
poor scrotal circumference (12%)
Physical defects: eyes and locomotor system,
physical abnormality that affects fertility (9%)
Young bulls are more likely to be disqualified due to poor morphology or small scrotal circumference (Tibari has this sentence highlighted).
What are some common congenital/hereditary defects affecting reproduction in the bull?
Persistent frenulum
Short penis
Phimosis
Morphological abnormalities in sperm (knobbed acrosomes, decapitated heads, dag defect, corkscrew defect)
What is your recommendation in the case of a persistent frenulum?
Most common penile problem in young bulls.
Treated bulls should be used as terminal sires = used to produce calves for slaughter, NOT breeding.
What type of anesthetic block is used for examination of the penis?
Pudendal nerve block: 20 ml of Lidocaine at level of the nerve
What is spiral deviation of the penis?
Penile deviations due to abnormalities of vasculature (shunts)
Moves away from the vulva prior to entry → can’t breed
NORMAL shape of the penis when in vagina @ time of ejaculation or when electrostimulated.
ABNORMAL when the penis is spiral shaped at all other times.
Discuss seminal vesiculitis in bulls:
Risk factors
Treatment
Prognosis
- Most common accessory sex gland disorder in bulls
- 2-4% in 2yr old bulls (as high as 50% in young bulls) <1% in older bulls
- Risk factors: Brucella abortus, Trueperella pyogenes, Histophilus somni, IBR, enterovirus, age, nutrition (high energy ration, acidosis), other infections (pneumonia, liver abscess)
- Treatment: spontaneous recovery possible in young bulls <2yr, Tulathromycin, Tilmicosin, cull bulls if >9yrs
- Prognosis poor if old; good if young
Discuss penile hematoma:
Risk factors
Treatment
Prognosis
- Risk factors: Breeding
- Conservative txt (lesion <20cm): broad spectrum Abx, hydrotherapy, sexual rest for 2 months, 60-70% return to breeding w/o sx
- Surgical txt (>20cm and <10days, but after 3-5 days): remove blood clot and repair rent, sexual rest for 60-90 days
- Prognosis: 75% bulls recover and return to breeding if sx is performed after 3-5 days, but within 10 days of injury.
Discuss preputial prolapse:
Risk factors
Classification
Treatment
Prognosis
Risk Factors
- discrepancy in cow/bull size
- breed: bos indicus - pendulous prepuce; polled bos taurus - absence of retractor preputial muscle
What is reproductive tract scoring, and how is it used?
Used to monitor heifer growth and cyclicity
Can also use to compare pregnancy rates for the season
What is the etiopathogenesis of pine needle abortion?
Isocupressic acid (ICA) - mechanism not fully known but thought to decrease uterine blood flow - abortion occurs after ingestion of 1kg of needles per day for several days
clinical signs
later pregnancy abortions
vulvar edema + mucoid bloody discharge in mid to late term
premature delivery, stillbirths, abortion, weak uterine contractions
dx: fetal thoracic + stomach fluid - tetrahydroagathic acid
tx: supportive, activated charcoal
Discuss the epidemiology of Foothill abortion.
Pcellulosum (Ornithodoros tick) vector = mule deer tick
Oregon, Nevada, California
Pathophysiology
- transplacental intracellular infection between 60-140 days of pregnancy
- slow progression (2-3 months) - late abortion
Fetal lesions
- not autolyzed, ascites, fibrin, swollen liver, splenomegaly
- petechial hemorrhage
Prevention
Decrease exposure to naive cattle during the breeding season
Trichomoniasis
Etiology
Pathogenesis
Symptoms
Diagnosis
Control
etiology
extracellular flagellated protozoa: tritrichomonas foetus
pathophysiology
bulls:
protozoa colonizes in epithelium of prepuce and penis
bulls become chronic carriers
cows:
venereal infection
inflammatory response - cervicitis, endometritis, pyometra, salpingitis
symptoms
bulls: no symptoms
cows: early pregnancy loss, abortion (<5mo), local immune response
herd: poor pregnancy rate, prolonged calving interval, increased pyometra
diagnosis
culture ID of parasite w/ PCR or microscopic exam
bull: preputial scraping
cow: pyometra fluid
fetus: abomasal content, IHC placenta + fetal tissue
prevention
cull open cows and those that aborted
purchase virgin bulls
test all bulls
vaccines - not very efficacious
biosecurity
Campylobacteriosis
Etiology
Pathogenesis
Symptoms
Diagnosis
Control
etiology
campylobacter foetus
motile gram (-), comma-shaped, hides in crypts of epithelial surface
pathophysiology
bulls: confined to epithelial surface of glans penis, prepuce, urethra
cow: inflammatory response: endometritis, salpingitis
symptoms
bull: asymptomatic, chronic carrier
cow: infertility, irregular estrus cycles
early embryonic death
placentitis
abortion (sporadic)
fetus: bronchopneumonia, pleuritis, peritonitis, hepatitis
diagnosis
culture + PCR
placenta
cervical mucous
preputial wash in bulls
prevention
immunization w/ bacterin
heifers: 2 injections 3-4 wks apart, 30d prior to breeding season (annual booster)
bulls: vaccine w/ 2 doses
biosecurity measures
use of AI
What is the etiopathogenesis of “Crooked Calf Syndrome”?
lupin toxicosis - acute fetal neurologic disease
ingestion between 40-100 days
alkaloids: Anagyrine (most common), Ammodendrine, N-methyl-ammodendrine
desensitization of skeletal muscle nicotinic AchR
decreased fetal movement
Arthrogryposis Multiplex
Cause
Methods of control
= lethal autosomal recessive genetic defect “curly calf syndrome”
angus breeds
affected calve are homozygous for the gene
permanent contracture of the forelimbs + hindlimbs
abnormal curvature of the spine
very small + lack muscle development
cleft palate
calves are generally stillborn or die shortly after birth
prevention
genetic testing of animals that have carriers in their ancestry
animals free of the gene are designated AMF (AM free)
only AMF bulls can be registered
Vaginal prolapse grading
