FAQ's - Oestrus management

General

• Oestradiol administration dramatically improves oestrus behaviour. Why do many experts consider that oestradiol should not be used as ovulation induction?
• Can oestrus synchronisation be applied in the herds that already are using heat watch or tail paint system?
• Which animals from the herd should be selected for the pharmacological management of oestrus?

Prostaglandins

• When is the best time to AI after single or double prostaglandin injection?
• I have initiated the oestrus synchronisation system with double prostaglandin injection but some cows are showing heat after the first injection of PG. Should they be inseminated?
• Why does the systematic administration of prostaglandins starting 14d post calving and continued every 14d sometimes result in poor conception rates even if the cows are served more often and uterine health improved?
  
• Are the results obtained with intravulvo submucosal (IVSM) administration of prostaglandins in reduced dose comparable to standard dose and administration routes?
• Is there a difference in time-to-oestrus between various prostaglandin analogues?

Ovsynch

• In the treatment scheme for Ovsynch there is a time window for AI of 16-24h post GnRH. What would be the optimum time?
• I wish to reduce the dose of GnRH used in the Ovsynch protocol. Is it better to reduce the first or the second one?
• Will I see a significant decrease in the results when using Co-Synch instead of Ovsynch?
  
• I have heard that the intensity of oestrus behaviour is lower with Ovsynch protocol than that of naturally observed or prostaglandin induced.
• Is it worth applying  Ovsynch in anoestrus cows?
• Can I use Ovsynch in beef cows and how?

Crestar

• How long will Crestar block the oestrus if not removed?
• Should I use the PMSG injection in cycling cows?
• Should I use prostaglandin injection in all cattle types or only in dairy?
  
• What dose of PMSG should be used with Crestar in zebu cows and crosses?
• Cow showing heat approx. 8 days after implant insertion
• What is the quality of oestrus behaviour observed with the use of Crestar?
• Does it make sense to add a GnRH at AI after the complete Crestar program?
• How is Crestar used in a suckled cow?
• Is there a risk that after repeated use of PMSG the antibodies against PMSG will be produced and interfere with the efficacy?