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Flashcards in dairy production lec 10 Deck (22):
1

what is the problem with small heifers

- small heifers
o high repro culling
o shorter herd life

2

what is the advantage of well grown heiffers

- well grown heifers
o tighter calving
o less induction
- higher MY over life time
reduced AFC

3

what problems do heifers risk

o Poor adaptation to changing diets
o Starvation or suboptimal nutrition
 biggest hazard
 protein and energy
 increased risk of diseases
o Parasitism and infectious disease
o acidosis
 poor transitioning
o Reproductive failure
o Calving

4

what is the association between LWFC and MY

• mature milk yield depends on LWFC
• higher LWFC can produce more milk
 want MY at first calving to be 80-85% of mature cows production

5

what is the target LW

 target LW depends on mature LW
• at joining should be around 60-65%
• by calving should be 90% of mature weight

6

how much does a heifer need to be growing

 need 0.7kg/day target growth average to reach

7

when should the AFC be

around 2 years
more flexible in a seasonal calving

8

what are the key management hazards in heifer growth

weaning management
disease and parasite management
nutrition
transitioning

9

what is the target weaning rate

varies 65-120 kg

10

what are the disease and parasite managements

drench, vaccinate and plant toxicities

11

how does a ration at weaning compare to first lactation

weaning has higher protein content similar energy 10 MJME

12

how much energy does a weaner need

10ME

13

why do you need to transition feed

 heifers need transition
• Rumen adaptation
• prevention of acidosis and metabolic problems
• Provision of energy and protein for foetus and udder development

14

how long is a transition feed

 >3 weeks on lead feed a risk for milk fever

15

what is happening during 6-12months

skeletal growth

16

what is happening during 12-15 months

puberty
key period for parasite control

17

what is happening during 15-18 months

joining
 target 350-390kg heifer
 maintain growth
• 9.5 MH/kg DM 16-18% CP

18

what is happening during 18-21 months

 early pregnancy
 still target growth
slightly lower protein and energy required

19

what is happening during 21-24 months

late preg
energy requirements increasing

20

what is happening during 23- 25 months

calving and lactation
energy requirements increase
need transition diet

21

what is the benefit of increased LW at first calving

o Improve milk production
 23L milk/kg heavier LWFC over 3 lactations
 heifer eats more-produce more
 bigger size so can compete for feed
o Improve fertility
 increased LW at mating = increased CR
• fewer empties
• increased CR
• tighter calving
o Reduce age at first calving (AFC)
 better economically
• quicker return
• longer milking life
 high AFC
• poor fertility/too small
• delayed joining
o Reduce dystocia
 dystocia can increase calving interval and lactation yield
 smaller heifers most at risk
o Reduce wastage (birth to 2nd calving)
 reduce culling before second lactation
 loose genetic advancement

22

what is the problem with heifers being too big

o fatty udder syndrome
 high growth on low protein diet prior and during puberty
 reduced feed efficiency
 lay down fat on udder