Parasite control for dairy cattle Flashcards
important dairy ectoparasites
Chorioptes
Lice
important dairy endoparasites
- Cryptosporidium
- Eimeria spp.
<><> - Hypoderma spp. ?
- Dictyocaulus viviparus ?
> these are problems depending on location and management (eg. pasture)
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GI nematodes > Parasitic gastroenteritis ? - Ostertagia
- Trichostrongylus
- Cooperia
<><><><> - question marks = only an issue on pasture
Macrocyclic lactones for cattle
- what do we use? milk withdrawls?
- invermectin
- injection: 60d
- pour-on: 60d
<><> - Doramectin
- Injection:60d
<><> - Eprinomectin
- Pour-on: 0 days
- Injection: Do not use
Drugs with a zero milk withdrawal
- Eprinomectin (Eprinex) Pour-on
- Permethrin (Boss/Vetolice) Pour-On
- Cyfluthrin (CyLence) Pour-on
chorioptic mange - when we see it
- common in Ontario – adult cattle indoors
- late winter/early spring
- impact on production ?
- lesions generally disappear after turnout
lice - when we see them
- relatively common in Ontario ?
- low #s on adult cattle – subclinical ?
- high numbers on young livestock
- indoors
- heaviest infestation - winter/early spring
- self cure in spring ?
when do we do preventative treatment for external parasites
fall - reduce burdens in the fall, so we dont get significant burdens in the winter
Cryptosporidium parvum
- when do we see it?
- control?
- prevention?
- very common infection
- typically 1-4 weeks of age
- should be controlled by attention to environmental hygiene and colostrum feeding
- preventive= halofuginone lactate (Halocur)
Eimeria spp. (coccidia)
- when we see it?
- prevention
- common infection?
- disease at > 2.5weeks of age
- calves commonly maintainedon coccidiostat (lasalocid, monensin, decoquinate) (toltrazuril = single PO)
Hypoderma spp. (warbles)
- where do we see it? who?
- when to treat?
- absent from southern Ontario?
- more common in younger cattle
- fall treatment before December = preventive
Dictyocaulus viviparus
- when is it a problem? control?
- uncommon in southern Ontario
- more common in younger cattle + at pasture
- disease in second half of grazing season
- should be controlled by GIN preventive program
Development of GINs in environment
- most important?
- stages? temp?
- when to we need prevention?
- Primary GIN in Ontario = Ostertagia
- L1, 2, 3 in feces; after that, off feces
<><> - Resilient stages: eggs + L3
> typically some will survive winter
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Development at 5-32C
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prevention required if cows go on pasture
<><><><> - Indoors or outdoors?
- Cattle in tie stall herds more likely to go to pasture compared to cattle in free stall herds:
- tie stalls: ~80% pasture
- free stalls: < 5% pasture - dry cows ?
- First season at pasture (whatever age) animals are immunologically naïve to GINs
Development of GINs in cattle
- where so ostertagia and cooperia live?
- PPP
- development of immunity
- seasonal development of parasite?
- egg count on pasture significance?
Abomasum: Ostertagia Small intestine: Cooperia
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Most significant facts:
1. Prepatent periods ~ 3 weeks
2. Development of immunity: a) rapid – Dictyocaulus (one grazing season required) b) slow - Ostertagia (multiple grazing seasons required)
3. Arrested development in fall in cattle.
4. Some Ostertagia over-winter on pasture in Ontario.
5. Poor relationship between fecal egg count and impact on production.
GIN infections in first grazing season if no deworming
- timing
- if you keep pasture free of cows until end of June, all parasites will die out
> but we usually turn out cattle in ~April
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Parasitic gastroenteritis in first grazing season
- disease presentations
Clinical (= type 1 ostertagiosis):
high morbidity ?
diarrhea, weight loss, anorexia, etc
moderate/high fecal GIN egg counts
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Subclinical + production loss:
reduced growth rates
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Subclinical + no production loss
Targeted control program
- objective and appoach
- Objective: Minimize patency in first half of grazing season
- Prevents accumulation of large #s L3 on pasture
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Approach:
1. Preventive grazing systems: - low stocking density
- pasture rotation
2. Targeted chemoprophylaxis
3. Monitor efficacy of regime
Timing of treatments ?
Duration of drug’s protection against Ostertagia vs PPP
(a) Ostertagia prepatent period = 3 weeks
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(b) Duration of drug’s protection against Ostertagia:
* SafeGuard Premix (fenbendazole) = 0 days * Ivomec Pour-On (ivermectin) = 14 days * Eprinex Pour-On (eprinomectin) = 28 days
targeted (minimum) intervals for ostertagia treatment
> based on length of residual activity
Non-persistent anthelmintics:
- first treatment at 3 weeks, second 3 weeks later
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Ivomec Pour-On (2 weeks activity):
- first treatment at 3 weeks, second 5 weeks later
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Eprinex Pour-On (4 weeks activity):
- first treatment at 3 weeks, second 7 weeks later
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Ideally, increase time before treatments by 1+ weeks
Second grazing season for ostertagia
- treatment protocol
- same protocol as first year ?
- if targeted regime was used in first year there probably is the need to be as aggressive
can you justify deworming adult cattle?
- commonly harbor low numbers of Ostertagia
- impact of >/= 1 treatment on milk production:
> 87 studies = -2.33 to +3.16 kg/day
> median = +0.63 kg/day (Gross et al. 1999) - number of calf treatments = main influence of response in cows (Bisset et al. 1987)
- Ontario–common practice to treat once/year in fall
