Non -infectious: ANOESTROUS

Question 1

Define anoestrous

Answer 1

Refers to failure of cows to enter oestrus or to be detected in oestrous
- Anoestrous is normal during the early post partum period
It is a major cause of reduced reproductive performance as it delays the time from calving to conception - increases culling rates and spread out the calving and weaning pattern

Question 2

What are the two types of anoestrous

Answer 2

Anovulatory - absence of oestrous behaviour is accompanied by failure to ovulate - Ovaries are smaller, C.f to cyclig cows - CL not present

Ovulatory - oestrous behaviour has not occurred or been detected but the animal has ovulated- 10-30% of cows

Question 3

Explain the physiological process involved arround anoestrous

Answer 3

GnRH and LH secretion are reduced during anoestorus. leads to more oestradiol receptors in the hypothalamus - enhances the negative feedback of oestradial on GnRH secretion

Question 4

How long does anoestrous last

Answer 4

Variable: 14 to 80days - commonly 20 to 40days
Chronically undernourished cow may fail to ovulate for > 1 year
First calf heifers = longer calving to first ovulation intervals - due to the strain on the negative energy balance

Question 5

strategies for minimising the duration of anoestrous and for treating anoestrus

Answer 5

Nutritional management and management of body condition
Genetic selection and heifer selection
Hormonal treatment

Question 6

what are some of the hormonal treatments that can be used for anoestrous

Answer 6

Progesteron treatment - helps to reduce the sensitivity of the hypothalamus to oestrogen negative feedback & reduces the incidence of short cycles following induction of ovulation