Lecture 7 Flashcards
Replacement groups include:
- preweaning calves
- weaned calves
- open heifers
- bred heifers
- springing heifers
After weaning the time of greatest risk of?
respiratory disease
Recommended weaning criterion?
calf eating 2lbs of starter per day for 3 consecutive days
minimum 3 weeks on starter
leave hutch or pen for 5-7 days after weaning
dehorn at 1-4 weeks
Eating dry feed(starter) helps develop the rumen by:
starts fermentation of nutrients in rumen
stimulates growth of rumen bacteria
growth of rumen papillae
growth of rumen muscle
Full rumen flora development takes how long?
3 weeks
Diet after weaning
mostly grain
free choice water
Bunk space for calves 2-18 months of age
> 12”
Bunk space for calves 18 months until transition
> 18”
Breeding goal for heifers
ready to breed at 13-15 months of age
Calving at how many months is ideal?
22-24 months
Consequences of overfeeding?
if too high in energy and not enough protein:
- difficulty calving
- difficulty conceiving
- reduced milk yield
Consequences of under feeding
stunted growth
delayed estrus
delayed conception
Minimum growth target for holstein heifers at pregnany(~15 months of age)
55% mature weight
330-385kg
48-50”
BSC= 3.0
Minimum growth target for holstein heifers at calving(24 months)
82-85% mature weight
500-595 kg
52-55”
BSC=3.5
Coccidiostats are class?
4
Coccidia pathogen?
protozoan parasite
Most infectious form of coccidia?
subclinical
-results in lack of growth
Lifecycle of Coccidia
- subclinical in small intestine(day 5 of life)
- marozoites infect large intestine(day 16)
- Diarrhea +/- blood, clinical in LI (day 18-19)
- Excretion of oocyts (day 22-25)
How coccidiostat works
- rumensin kills cocidia before thy invade the small intestine
- rumensin kills coccidia emerging into the lumen of the small intestine
- rumensin kills coocidia emerging into the lumen of the large intestine
- rumensin reduces the opportunity for reinfection by reducing oocyts shedding
Preventative measures for coccidia
- avoid fecal contamination
- clean calving pens regularly to avoid buildup
- all in/all out calf hutch management
- minimize contact between calves
- prevent over grazing pastures
- Water sources above ground
Life cycle of a GIN
- Eggs passed in feces
- in the warm sun eggs hatch and mature through stages L1-L3
- L3 crawl off fecal pat onto grass so more likely to be eaten
- L3 are eaten and mature to L4 and adults in abomasum
- GIN suck protein from abomasal wall
- Produce eggs 21 days post infection
Which stage of the larva is infective in GIN?
L3
How does raking of pasture prevent GIN?
dries the patties and killing in L1 and L2 stage
Parasite burden in pasture dependent on?
cattle density
weather(cool, wet)
sharing of pastures by adults and heifers
rotation of pastures + rotation of animal species
deworming program for heifers and cow
Ostertagia is?
brown stomach worm
Ostertagia affect?
abomasum
Type 1 ostertagiasis will see clinical signs if?
Parasite load is high enough
cattle are young
Type 1 ostertagiasis clinical sings
diarrhea anemia weight loss or poor weight gain protein loss and debilitation large # of eggs in feces death
Type 2 ostertagiasis
in fall L4 go dormant in wall of abomasum(hypobiosis)
emerge in spring to feed and produce eggs
If heavy enough load of type 2 ostertagiasis side effects include:
severe clinical disease and death
often no egg in feces because too early in life cycle
Developmental issues associated with parasitism
inefficient use of feed
delayed pregnancy
undersized at calving
Anthelmintic strategy for parasites depends on?
parasite load on pasture
product
target parasites
Difference between pour on and oral/injectable anthelmintics?
pour on= kill hypobiotics, residual activity(15-56 days)
oral/injectable= cheaper, no residual activity
Causes of anthelmintic resistance
- under dosing
- no evidence of loss of resistance
- pasture management
