- An internal prolonged estrus appears in 10 % of cows.    

- The external symptoms of estrus are normal.

- History of poor conception rates accompanied by prolonged estrus may indicate that delayed ovulation takes place or that the follicle fails to ovulate.

- Rectally, there is no ovulation within the normal time (10 –18 hours after end of heat).

- Ovulation occurs 24 –72 hours after heat and about 50% of cows give normal ova.

- Conception after mating or A.I. is reduced due to:

• Aging of the oocyte within the follicle
• Sperm aging
• Changes in the oviduct environment

- The animal shows signs of repeated breeding.

Treatment:

-- Apply a second insemination 72 h after heat.

-- Inject LH 5000 IU or GnRH (100 µg) for cattle at the time of AI or up to six hours beforehand

- Don't try to squeeze the G F.