Term
| What are the biotypes of BVDV? |
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Definition
Cytopathic (CV) strains kill cells in culture
Noncyotpathic (NCV) do not. These are associated with PI animals |
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Term
| What is a PI infection with BVDV? |
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Definition
A persistently infected calf due to being exposed as a fetus during the first 125 days of gestation
-virus is not recognized as non-self by the immune system
-will shed the virus their entire life
-will often die before adulthood |
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Term
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Definition
-direct contact with the shedder
-shed in saliva, mucus, semen, manure
-can also be transmitted in utero (PI calfs!) |
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Term
| Which genotype of BVDV is more acute & more easily shed? |
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Definition
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Term
| Describe the characteristics of a BVDV infection |
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Definition
-virus replicates in upper resp tract & lymphoid tissues
-destroys lymphoid tissues = immune suppression
-virus in blood stream 3-10 days after infection
-may be as short as 2-3 days for some cattle
-70-90% are subclinical |
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Term
| What are some of the risk factors for BVD disease? |
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Definition
Poor herd immunization
-no modified live virus used, or didn't give primary killed vaccine
Animals are purchased
-without screening for BVD
-no quarantine period |
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Term
| What are the clinical presentations of BVDV? |
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Definition
Mucusal disease (only in PIs)
Peracute BVD
Acute BVD
Immune suppression & secondary pneumonia
Reproduction problems, abortion, congenital anomalies |
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Term
| What is the difference between peracute and acute BVD? |
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Definition
Peracute
-high fever, off feed, diarrhea, death
Acute
-fever, diarrhea, pneumonia, abortion |
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Term
| Describe the incidence & effects of mucosal disease |
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Definition
-in PI animals
-low morbidity, 100% fatality
-fever
-oral erosions
-diarrhea, sometimes bloody
-death in 5-7 days |
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Term
| What happens if a PI animal is exposed to a CV strain of BVDV? |
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Definition
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Term
| Describe the patterns you would see in a herd following introduction of the BVDV virus |
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Definition
1. Acute disease in susceptible animals
2. Abortions & early embryonic death
3. Weak or deformed calves
4. PI animals
5. Death of more animals |
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Term
Describe the reproductive manifestations of BVDV if a cow is exposed at:
Breeding - 42 days gestation
70-125 days gestation
100-170d gestation
170-280d gestation |
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Definition
At breeding: inhibited conception or EED
70-125d: PI calves
100-170d: congenital anomalies or abortion
170-280d: no fetal harm, will be born with antibodies to the disease |
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Term
| Describe some of the congenital anomalies seen in calves exposed to BVDV in-utero |
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Definition
cerebellar hypoplasia (inhibited motor control)
blind or cataracts
lack of hair |
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Term
True or False
A PI dam is not necessarily going to give birth to a PI calf |
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Definition
false
Will always give birth to a PI calf |
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Term
| Describe the economic costs of BVDV |
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Definition
-very few infections are clinical
-acute disease of a pathogenic strain can kill 25-40% of infected animals
-severe milk reduction
-weight loss
-abortions
-persistent reproductive problems in the herd |
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Term
| What is the recommended treatment for BVDV? |
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Definition
-no specific treatment
-supportive care & antibiotics for secondary infections resulting from acute BVD
-PI calves will generally die, should be euthanized to prevent spreading and end suffering |
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Term
| What are some critical management considerations to prevent or eliminate PI animals & prevent acute disease? |
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Definition
-effective vaccination program
-MLV to protect fetuses
-quarantine new animals & test for PI
-vaccinate new purchases while in quarantine
-isolate animals with diarrhea & respiratory disease |
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Term
True or False
Salmonellosis is a host-adapted virus |
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Definition
False
Host-adapted and non-host adapted strains exist
More serious effects will be seen if a non-adapted strain infects a host |
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Term
| Describe the pathology & clinical signs of Johnes disease |
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Definition
Pathology
-slow growing bacteria mainly in ileum
-intestines thick with bacteria & inflammatory cells
-malabsorptive diarrhea
Clinical Signs
-profuse diarrhea
-good apetite yet weight loss
-no fever
-reduced milk production in sub-clinical cases |
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Term
| What is the best course of treatment for Johnes disease? |
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Definition
-no effective treatment
-selective slaughter of affected animals
-blood & milk tests, fecal cultures |
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Term
| What are the clinical signs of salmonellosis? |
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Definition
-bloody diarrhea with fibrin
-fever
-off feed
-reduced milk production
-abortions
-calf septicemia, can be fatal |
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Term
| How is salmonellosis transmitted? |
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Definition
| Primarily through feces, but also oral/nasal/urine shedding in septicemic cases |
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Term
| What does it mean that salmonellosis is an opportunist disease? |
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Definition
A low dose of exposure will affect cows with suppressed immune systems, e.g. post-partum, and calves
Healthy cows need a higher dose of exposure to be affected |
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Term
| What are the critical control points for salmonellosis? |
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Definition
-restrict movement of manure between herds
-separate hospital & calving pens
-rational antibiotic use so you are not killing 'good' bacteria
-separate calves & cows in outbreaks
-cannot vaccinate for salmonellosis! |
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Term
| How is Johnes disease transmitted? |
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Definition
fecal-oral
(shed in manure, ingested through contaminated feed, pasture, water etc)
-can be transmitted from dam to fetus in advanced stages |
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Term
| Why is prevention/control of Johnes disease a challenge? |
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Definition
Seems to only affect calves if exposed at less than 6 months of age
-Clinical manifestation of the disease will happen years later, 2-6 yrs of age |
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Term
True or False
Bacteria of Johnes disease can survive years on pasture |
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Definition
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Term
| What are the critical control points for managing Johnes disease? |
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Definition
-prevent manure movement from adults to calves
-ID and quickly remove infected individuals
-clean maternity pens & immediately remove calf
-do not pool colostrum together
-don't feed leftover feed to heifers
-avoid spreading manure in same year as forage |
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Term
| What are the chief stages/goals in biosecurity programs? |
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Definition
1. Prevent introduction of pathogens to farm
2. Prevent movement of pathogens within the farm
3. Prevent transfer of pathogens to humans |
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Term
| Name some items on the 'A' list of biosecurity |
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Definition
-effective vaccination programs
-hygienic milking
-restrict manure movement
-isolate sick animals
-separate sick & maternity pens
-no colostrum pooling
-remove deadstock, culled cows
-disease monitoring programs |
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Term
| Name some items on the 'B' list of biosecurity |
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Definition
-selective sourcing of purchases
-maximize knowledge of source
-test animals before introduction
-use milk replacer, not pooled colostrum
-metaphylactic treatments |
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Term
| Describe the structure of placentation in ruminants |
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Definition
Caruncle - maternal side of placenta
Cotyledon - fetal side of placenta
Placentome - Caruncle + Cotyledon |
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Term
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Definition
A heifer born co-twin to a male, with genotype XX/XY
-androgenous female sex characteristics, abnormal external & internal genitalia
-95% are sterile
e.g. may have ovaries & a vagina but no cervix or uterus |
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Term
| What is abortion? What might cause this? |
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Definition
premature expulsion of embryo or non-viable fetus from the uterus
-impaired function of the placenta
-infectious or non-infectious damage to fetus |
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Term
| What are some causes of non-infectious abortion? |
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Definition
-twins
-heat stress
-fatal genetic anomalies
-maternal disease e.g. mastitis
-infectious contributors e.g. BVD, leptospirosis |
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Term
| What is infectious sporadic abortion? |
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Definition
-introduction of disease agent through circulation or up repro tract
-can be fungal or opportunistic bacteria
-not a huge risk to rest of herd as not highly contagious |
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Term
| What are some contagious agents that cause cause abortions? |
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Definition
Leptispirosus
Infectious Bovine Rhinotracheitis
Bovine Virus Diarheea |
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Term
| What is neospora caninum? What does it cause? |
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Definition
-coccidian parasite which infects cattle & dogs
-lifelong infection
-manifests itself as abortion
-if fetus is not aborted,the calf is very likely infected
-no effective treatment |
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Term
| What is horizontal vs vertical transmission of Neospora caninum? |
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Definition
Horizontal: from dog to cattle through do feces, or cattle to dog through cattle tissue
Vertial: from cow to fetus |
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Term
| What should you do manage Neospora caninum in a herd? |
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Definition
-cull cows which have aborted due to neospora
-do not breed seropositive cows to replace heifers
-could do ET a seronegative recipient of an infected cow has desirable genetics |
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Term
| Describe Stage I of parturition |
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Definition
-relaxation of pelvic ligaments & cervix
-fetus changes position
-rhythmic contractions push placental mmb against cervix
-can take 2-3 days |
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Term
| Describe Stage II of parturition |
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Definition
-rupturing of allantois & amniotic sac
-abdominal & uterine contractions expel fetus from uterus
-2 to 4 hours to complete |
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Term
| Describe Stage III of parturition |
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Definition
-expulsion of fetal membranes (<12hours)
-uterine involution (<28 days) |
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Term
| What are the 3 'P's of calving? |
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Definition
Presentation - head first!
Position - upside down vs right side up
Posture - how head & legs are |
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Term
| What are some causes of dystocia? |
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Definition
-failure of cervix to dilate
-obstruction of vagina (too much pelvic fat)
-failure of vulva/vagina to dilate
-uterine torsion
-uterine inertia (exhaustion, milk fever)
-fetus is too large for pelvis
-abnormal presentation
-twins
-malformed fetus |
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Term
| What are some things to consider when assisting in calving? |
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Definition
-maximum force to be used is 2 peoples arms
-keep things sanitary, use lube
-follow natural downward arc
-rotate calf during delivery |
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Term
| What are some of the consequences of dystocia? |
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Definition
-death of fetus
-vaginal tears
-uterine tears
-obturator nerve paralysis (calving too tight)
-sciatic nerve paralysis (down too long)
-muscle damage due to being down |
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Term
| What is the term for a difficult calving? |
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Definition
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Term
| What is postpartum involution? |
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Definition
restoring the repro tract so it can support another pregnancy
-shrinkage & repair of uterus and cervix
-sloughing of caruncles, repairing endometrial epithelium
-clearing of bacterial contamination |
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Term
| What is postpartum anestrus? How would you treat this? |
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Definition
-cows don't return to regular estrus cycle by 60d post-partum
-may be more pronounced in 1st lactation
-associated with body condition
-difficult to identify affected individuals
-supply progesterone to treat |
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Term
| What are the risk factors for a retained placenta? |
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Definition
-dystocia
-twins
-abortion
-milk fever
-C section
-induced delivery |
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Term
| What is the root cause of a retained placenta? |
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Definition
impaired immune function inhibiting detachment of the placentome
-neutrophils have reduced chemotaxis at calving, reduced killing capacity post-partum |
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Term
True or False
Uterine motility is reduced in cows affected by a retained placenta |
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Definition
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Term
| What are the impacts of a retained placenta? |
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Definition
| RP itself is not directly harmful, but there is a greatly increased risk of metritis, endometritis |
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