This document discusses estrus synchronization in farm animals. It describes the typical length of estrus cycles in various species, ranging from 16-26 days generally. The phases of the estrus cycle are also outlined. Factors that can affect the cycle are then listed. Requirements and methods for estrus synchronization are explained, including using prostaglandins or progestins. Advantages and disadvantages of synchronization are provided. Specific synchronization protocols for sheep/goes and cattle are also summarized.

1. How to event synchronization in farm animals

2. THE OESTROUS CYCLE AND ITS PHASES:
The oestrous cycle is the sequence of hormonal changes that occurs through
the ovarian cycle. These changes influence the behavior and body changes of
the female. Controlled by LH&FSH. The average length of the estrous cycle is
similar for all farm species, with shorter in ewe. It is about 17 days in ewe; 21
in cow, water buffalo and doe; 22 days in mare; 20 days in sow. Individual
variation is seen in all species. Estrous cycle ranging between 17 – 24 days are
considered normal in the cow; 17- 26 days in the water buffalo; and 19 – 25
days in the mare; 16 -17 days in ewe; 15 – 24 days in doe; 15 – 21 days in
queen cat; 18 – 24 days in sow; and 1 – 4 cycles in a year in bitch.
1- Pro-oestrus phase
2- Estrus phase
3- Metestrus phase
4- Diestrus phase
5- Anoestrus

3. • Factors affecting the estrous cycle:
• 1- Environmental temperature
• 2- Nutrition
• 3- Seasonal influences and light
• 4- Age
• 5- Character of work
• 6- Transportation
• 7- Systemic diseases
• 8- Pathology of the uterus or cervix
• 9- Endocrine disturbances
• 10- Miscellaneous causes

4. Physiological Requirements for Estrous Control
1.Follicle wave control –fertile oocytes -precise estrus –synchronized
ovulation
2. Synchronous decline in progestin
-CL regression -precise estrus
Optimal Program
3. Induce onset of estrus in anestrous females
-opportunity for AI -shorten postpartum anestrus.
Estrus synchronization Why?
1. Group females for parturition
a.Labor, Calving period
b. More uniform weaning weights.
2. Reduce or eliminate estrus detection.
3. Needed for artificial insemination
Reduce calving season

5. Synchronization methods
• Prostaglandins
• Naturally occurring hormone that causes regression of the CL
(luteolysis) and decreases progesterone secretion which results in a
return
to estrus
• Can expect estrus within two days following injection
• Protocols include PGF one-shot method and PGF
two-shot method
Progestins
• Form of progesterone that extends the period of time progesterone is
present and prevents animal from coming into heat
• Protocols include MGA prostaglandin and CIDR

6. Advantages of synchronized ovulation
• Can synchronize large group to ovulate at same time
• Shorten calving season
• Reduce labor required for AI breeding
• Reduces overall management problems with AI
• Market uniform calf crop (same age)
• Improves management practices (cattle grouped-closer
observation, better feeding practices, etc.)
Disadvantages of synchronized ovulation
• Low conception rates
• - Cost
• - Concentrated labor required during breeding and calving
season
• - Cows all calving at once (especially bad if have many calving
problems)

7. Synchronization in the Ewe
• Most common protocols use
prostaglandins or CIDR

8. • Sheep and Goats Synchronization Ewes estrus (16 days)
Does estrus (21 days)
• Progestogen (implant or pessary)
• Implant 12-14 days sheep
• Implant 18-21 days goats
• Inject eCG 400-800 IU at withdrawal
• TAI ewe at 48-60 hrs and does 30- 48 hrs after
progestogen withdrawal
• PGF2?
• Ewes 2 injection 9 days apart double AI at 2-3
days
• Does 2 injection 11-12 days apart AI or natural
mating at 2-3 days

9. • Cattle synchronizationPGF2?
• Two PGF2? 11-14 days apart
• Estrus 72-96 hrs
• Progestogen and PGF2?
• Vaginal pessary CIDR or PRID 7 days
• PGF2? inject at 6 days
• AI at Estrus (48-72 hrs)

10. References
• Abdullah, A. Y. ; M. Q. Husein and R. T. Kridli (2002). Protocols for estrus
synchronization in Awassi ewes under arid conditions. Asian- Aust. J. Anim. Sci.,
(15):957-62.
• Dogan, I. and Z. Nur (2006). Different estrous induction methods during the non-
breeding season in Kivircik ewes. Vet. Med. Czech. (51): 133-138.
• Zonturlu, A. K. ; N. Özyurtlu and C. Kacar (2011). Effect of Different Doses PMSG on
Estrus Synchronization and Fertility in Awassi Ewes Synchronized with Progesterone
During the Transition Period. Kafkas Univ. Vet. Fak. Derg., 17 (1): 125-129.
• Suadsong S. Control of estrus and ovulation in cows. Thai J Vet Med. 2011; 41:95-98.