Dairy Flashcards
What is the dairy cow cycle?
Insemination, pregnancy, parturition, and lactation, followed by a dry period of about 2 months which allows udder tissue to regenerate
What are the main two parts of the dairy operation in regards to the cows themselves?
Milk production and calves to be reared as future replacements. Bull calves are sold at about 4 days of age or castrated and raised as steers for beef production (dry umbilical cord, in VIC they must be ear tagged)
What percent of Australian milk is exported?
55%
Where is 80% of Australian milk sent?
Asia and the Middle East
What is the avg. annual milk production per cow in AUS?
5,445 litres
When does milk production peak in Australia?
October because of seasons and rain and feed.
Why is a tight calving period important for dairy cows?
Late calving cows spend a smaller period of their time at high levels of production because cows reach a peak of production after 6-8 weeks of milking, maintaining a level of production for 2-3 months depending on feed availability.
What is split calving?
Herds that calve in two or three distinct periods each year; commonly spring and autumn. Particularly common in non-irrigation areas; production of milk year round- more efficient for manufacturers
What are the consequences of a non-pregnant cow (3)?
Culling the cow, carrying a dry cow over a whole season, milking the stale cow through
What are the benefits of year round calving in dairy cows?
Fewer cows sold as empty or late, more rapid genetic gain, less resources directed at correlating poor performance, more calves
What is the benefit of heavier heifers in dairy cows?
Reach puberty at a younger age, calve earlier, compete well, cycle earlier, and have higher peak milk yield, longer lactations and have superior lifetime production
What does colostrum provide in dairy cows? How much does the baby need in dairy cows?
Essential immunoglobulins (IgG)- immunity, excellent nutrient source, 5x protein, higher energy and vitamins than milk. 3.5-4 lit
What is the timing of colostrum? Max time and ideal time. Why?
has to be less than 12 hrs, ideally between 2-4 hours. Due to intestine failing to absorb intact macromolecules after 12-24 hours.
How do you assess adequacy of passive transfer in dairy cows?
take blood from calves 24-48 hours old and up to 7 days of age. Adequate IgG> 12 gm/L
Failure passive transfer IgG< 8 gm/L
Partial failure IgG 8 gm/L
When does the rumen develop in dairy cows?
6-8 weeks
How much protein does a calf need in dairy cows?
20-22%
How much volume of milk should a calf be fed daily?
10-12% body weight; twice daily for 1st week then once daily thereafter
When do you start feeding dairy cows grain?
From 1st week of life (small amount fresh daily), ad lib access to water, feed starter composition 18-20% crude protein
When are calves weaned in dairy cows?
1-3 days really.
6-8 weeks, weight 70-80 kg, intake 0.75-1.5 kg/day (best method)
What are the causes of calf scours?
Dietary- undigested milk in SI unclotted 1st week- E. coli 1-2 weeks- Salmonellosis 1st month- Cryptosporidosis Viral- Rotavirus causes watery yellow diarrhoea >3 weeks- Coccidiosis
What are some problems associated with undersized heifers?
Calving problems, produce less milk, and have greater problems getting back in calf during 1st lactation
When does the rumen reach mature capacity?
5 or 6 months of age.
When are foetal membranes expelled in dairy cows?
Within 12 hours of calving (sometimes 2-7 days)
What do farmers in SE Australia feed their cows?
Mostly pasture (75% of diet) of daily dry matter intake, grain, concentrates, or grain mixes
A cow in peak lactation requires how much DM per day?
18-20 kg of DM/day
What is the stocking rate for lactating dairy cows?
2.5-3 cows per Ha
WHat is ideal grazing in terms of grass DM/Ha for dairy cattle?
2000-3000 DM/Ha
What is the benefit of supplementary feeding in dairy cows?
Increasing amount of milk production per cow and also increase milk fat and protein levels
What is the recommended levels for action in regards to mastitis?
Bulk Milk Cell Count above 250,000 cells/ mL OR 5 clinical cases per 100 cows in the 30 days after calving OR 2 clinical cases per 100 cows per month during lactation OR 5 new infections per 100 cows in milk
What is the target weight for a Jersey cow?
300-320 kg
What is the target weight for a Friesian cow?
350-400 kg at 15 months
How many lactations in a cow’s lifetime in dairy cows?
6 lactations
What are some of the signs of heat in a cow?
sniffing other cows, mounting, mucus discharge, behaviour changes, squirting urine frequently, swollen volva, turn her head to her flank
How long does oestrus last in dairy cows?
1-2 hours to 28 hours
When does ovulation occur in dairy cows?
12 hours after oestrus
When does prostaglandin produce oestrus in dairy cows if given between day 6-15 of the cycle?
2.5-5 days after injection
What is another option other than prostaglandin to induce oestrus in dairy cows?
Progestagens (e.g. CIDRs) problem is that fertility synchronization may be compromised
What is the 21 day submission rate in dairy cows?
Is the proportion of the herd detected in oestrus and submitted to service in the first 3 weeks of mating. Depends on whether the cows are cycling, whether the cycling cows are on heat, whether those cows on heat are actually mated
86% is achievable
6 week in calf or pregnancy rate in dairy cows?
21 week in calf rate?
Number of cows that were diagnosed as pregnant during first 6 weeks of mating period divided by number of cows in the herd (71 % achievable)
* number of cows which conceived during first 21 weeks of mating/ number of cows in the herd (92% achievable)
How many bulls for how many not pregnant females (mop up bull)?
1 bull for 30 not pregnant females
What percentage of dairy farmers use AI?
84% (lower for year round calving herds and small herds)
What is the conception rate in dairy cows?
Percentage of services that resulted in pregnancy (target 53%)
What is the non-return rate in dairy cows?
Estimate of conception rate based on proportion of cows for which no subsequent oestrus detected in a specified time (target >65%)
What is the size of the national dairy herd?
1.63 million
How many registered dairy farms in AUS?
6,700
Where does dairying occur?
Follows higher rainfall belt along southern and eastern coasts of Australia
What percent of the world trade does Australia account for in dairy products?
7%. Only 2% of the world milk production. Principal exports are skim milk powder, cheese, butter and whole milk powder.
How many litres of milk produced in AUS in 2012?
9480 million Liters
What is the average dairy cow herd size?
240 cows
What percentage is seasonal calving, split calving, and year round?
seasonal calving- 36%, split calving- 33%, year round 32%
Where is the VIC dairy industry?
Western District (dryland)- major dairy region in AUS, Gippsland (dryland)- eastern VIC (land prices taking a toll), Northern VIC (irrigation)- formerly most productive region but had a drought
What is seasonal calving?
Calve whole herd in about 10-12 week period (spring or autumn)- pasture growth is seasonal.
