Term
| What are the 2 largest economic inputs in dairy farming? |
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Definition
feed costs
replacement heifers |
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Term
| What are the goals of a replacement program? |
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Definition
produce enough replacements to maintain a milking herd
-efficiently
-calve successfully
-on average better than the cows they are replacing |
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Term
| What is the optimal age at calving for milk production? |
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Definition
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Term
| What factors must be considered in a health management program for dairy heifers? |
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Definition
weaning
housing
nutrition to achieve growth targets
vaccination program
parasite control
mastitis control |
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Term
| What are the minimum growth targets for heifers at pregnancy and at calving? |
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Definition
Pregnancy: 330-385kg, 55% of mature weight
Calving: 500-595kg, 82-85% of mature weight |
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Term
| At what age does mammary development begin? |
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Definition
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Term
| What is the optimum growth rate from 150-320kg? |
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Definition
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Term
True or False
Increasing the pre-weaning growth rate of a replacement heifer has shown to increase the milk production during the 1st lactation |
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Definition
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Term
| What are the types of replacement groups for heifers? |
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Definition
1. Pre-weaning calves
2. Weaned calves
3. Open heifers
4. Bred heifers
5. Springing heifers |
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Term
| What period of time is the greatest risk of death in a dairy calf's life? |
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Definition
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Term
| What period of time is the greatest risk of disease in a dairy calf's life? Why? |
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Definition
after weaning
Lots of changes during weaning, diet, social, housing etc. |
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Term
| When managing weaning, what are some important basic considerations? |
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Definition
-groups of 5-8 calves
-at least 25sq ft of bedded area
-mostly grain diet with forage introduction as well
-free choice water |
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Term
| What effect does restricted bunk space have on growth? What is the recommended bunk space for calves? |
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Definition
increases variability in growth, but not the average growth rate
>12" for 2-18 months
>18" from 18 months until transition |
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Term
| What are the recommended criteria for weaning? |
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Definition
-calf eating 2lbs of starter per day for 3 consecutive days
-on starter for minimum of 3 weeks |
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Term
| How much water will a weanling calf drink? |
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Definition
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Term
| If a calf is eating 2lbs of starter per day for 3 consecutive days, what does this indicate? |
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Definition
| that the rumen is well developed enough to survive on solid feed (takes approximately 3 wks) |
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Term
| How long should a calf be left in a hutch or pen post-weaning? |
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Definition
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Term
| At what age should you dehorn? |
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Definition
1-4 weeks
not at same time as weaning, too much stress! |
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Term
| Why is it important to gradually wean a calf? |
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Definition
-need time for growth of rumen papillae, depends on VFA's in rumen from grain fermentation
-need time for growth of rumen muscle, which depends on the bulk contents of the rumen |
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Term
| Why would the rumen of calf fed a diet of milk, grain and hay be darker than that of a calf fed just milk and hay? |
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Definition
| the rumen is better developed, with more papillae and lots of blood vessels |
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Term
| What do coccidiostats? Why are they included in diets? |
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Definition
agents added to feed which inhibit growth of coccidia bacteria
-exposure to this bacteria is common, effects can be significant, inhibiting growth |
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Term
True or False
Cattle gradually develop an immunity to coccidia over time |
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Definition
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Term
| Name an effective coccidiostat |
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Definition
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Term
| What is the challenge with feeding coccidiostats in a group setting? |
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Definition
| The diet is formulated for the 'average' calf in the group, and it's hard to ensure that all calves are getting the correct amount |
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Term
| What effect does bovine respiratory disease have on growth & weight of weaned calves? |
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Definition
| -slows growth rate, will have a final lower weight than healthy calves and a smaller ADG |
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Term
True or False
Probability of calving in the future is not affected in calves with BRD |
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Definition
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Term
| Why is calf nutrition, health and housing an important concern for calves being raised as replacement heifers? |
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Definition
| nutrition, health & housing at less than 16 weeks of age will affect age, weight and body score at calving in the future! |
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Term
| What internal parasites affect the abomasum? |
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Definition
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Term
| What internal parasites affect the small intestine? |
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Definition
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Term
| Describe the life cycle of an abomasal gastrointestinal nematode |
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Definition
-eggs are passed in feces
-eggs hatch & mature to L3 in sun (infective stage)
-L3 crawl of feces onto grass, are ingested
-mature to L4 and adults in abomasum
-GIN suck protein from intestinal wall
-produce eggs 21 days post infection |
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Term
| What factors affect parasite burden in pasture? |
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Definition
-cattle density & age of cattle
-weather
-annual pasture rotation
-rotation of species in pasture
-deworming program |
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Term
True or False
Animals are naive to GINs until they have been exposed to pasture |
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Definition
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Term
| What is Type I ostertagiasis? |
|
Definition
Type 1
-young cattle, 1st or 2nd season on pasture
-clinical parasitism
diarrhea, weight loss, poor weight gain, protein loss, large # of eggs in feces, death |
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Term
| What is Type II ostertagiasis? |
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Definition
L4 go dormant in wall of abomasum in fall
-will emerge in spring to feed & produce eggs, and a heavy enough load will cause clinical disease & death
-often no eggs in feces as it's too early in the life cycle |
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Term
| How can you diagnose GIN & coccidia? |
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Definition
| microscopic examination of fresh feces for presence of eggs |
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Term
True or False
There is a direct correlation between fecal egg counts and parasite burden in adult cows |
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Definition
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Term
| What are the typical sub-clinical effects seen due to parasitism? |
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Definition
-inefficient feed use
-delayed pregnancy
-undersized at calving |
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Term
| When are the important times to deworm? |
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Definition
-at turnout
-3-11 weeks after turnout
-at end of pasture season |
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Term
| What are some of the methods available to treat parasites? |
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Definition
-pour-on treatments
e.g. ivermectin, moxidectin
broad spectrum, and have residual activity
Kill L4 stage
Oral/injectable adulticides
e.g. fendendazole
cheaper, no residual activity |
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Term
| What effect does deworming to treat parasitism have on dairy heifers? |
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Definition
| 0.1-0.2kg/day difference in weight gain |
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Term
| Define metritis, endometritis & pyometra |
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Definition
Metritis: systemic illness, fever, off feed, uterine infection
Endometritis: no systemic signs, infection/inflammation of the uterus
Pyrometra: distended uterus with pus |
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Term
| Describe the clinical signs of metritis & typical treatment |
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Definition
-fever, off feed
-may have a retained placenta
-watery, red-brown uterine discharge
Treatment: systemic antibiotics |
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Term
| What should a normal uterine discharge look like? |
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Definition
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Term
| Metritis is largely a function of _____ |
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Definition
| postpartum immune function |
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Term
True or False
There is no link between post-partum metritis and DMI |
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Definition
False
Cows with metritis also had lower DMI both before and after parturition |
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Term
True or False
Almost all cows have a uterine infection post-partum |
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Definition
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Term
| What are the the typical bacteria causing uterine infections? |
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Definition
E.coli in week 1
Trueperella pyogenes in weeks 2 & 3 |
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Term
| Given that all cows have some form of uterine infection post-partum, why are some affected by metritis / endometritis and some are not? |
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Definition
| There are differences in the magnitude, regulation, duration and effectiveness of the immune response |
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Term
| What is endometritis? What is the conventional treatment? |
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Definition
Localized inflammation of the uterus characterized by prolonged involution
Treatment: antibiotics 4-6 weeks postpartum |
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Term
| What are the types of endometritis? |
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Definition
Purulent vaginal discharge (15-20%)
Sub-clinical (15-20%)
Both 5-10% |
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Term
| What are the economic impacts of endometritis? |
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Definition
-more days open
-failure to become pregnant
-culling
-increased early pregnancy losses
-treatment cost & milk discard (bc antibiotics) |
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Term
| What is a cystic ovary? How is it treated? |
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Definition
follicle fails to ovulate or grows to abnormal size
-ovum will age, be infertile
-can treat with lutenizing hormone to stimulate ovulation |
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