Summary of the Signs of Infertility

The following summary of the signs of infertility briefly describes a procedure for investigating an infertile animal on the basis of clinical history, signs and examination with an indication of possible diagnosis.

No Observed Estrus

• Palpate per rectum for pregnancy.
• If there is any doubt re-examine at a latter date.
• If not pregnant palpate ovaries.

Ovaries

• If the ovaries are small, narrow and functionless in a heifer, then this may be due to
  • Delayed puberty
  • Ovarian hypoplasia
  • Possibly freemartinism
• Flattered, smooth, small and inactive ovaries.
  • anestrus
• Presence of CL
  • Pregnancy
  • Non detected estrus
  • Silent estrus
• Small active ovaries
  • Proestrus, estrus or metestrus.
  • Re – examination after 10 days for confirmation of CL.
• Large ovaries
  • Ovarian cysts (luteal).
  • One or both ovaries enlarged containing fluid filled thick walled structures.
• Persistant CL
  • A persistent CL may be associated with pyometra, chronic endometritis, mummified fetus etc.,
  • Careful examination of uterus helps to diagnose the case.

Prolonged Interestrus Interval

• Non detected estrus
• If the interval between successive heats is approximately twice the normal interval i.e., 38 – 48 days then this indicates one estrus has been missed.
• Embryonic or fetal death.
• The interval between successive heats will not be in the multiple of 21 (eg.) 30 days. In individual cow it is not of much significance. If a number of animals are involved especially if natural service is used, specific pathogens should be eliminated.

Regular Return to Estrus (Repeat Breeder)

• Poor quality semen
• Check the semen quality and general fertility
• Incorrect timing of AI or service
• Unlikely to occur repeatedly
• Nutritional deficiency of excess
• Check diet
• Anatomical defects
• Check for adhesions
• Occulded uterine tubes
• Carefully palpate or use PSP dye test
• Endometritis
• Clinical signs
• Delayed ovulation / anovulation
• Long estrus
• Luteal deficiency

Short Inter-estrous Interval

• Enlarged ovaries.
• Cystic ovaries / follicular cyst.
• AI at wrong time.
• Endometritis.

Correct Timing of Artificial Insemination

• The estrus is short in the cow 12-24 hours.
• Ovulation occurs 10-12 hours after the end of the estrus.
• Best conception rates occur if inseminated in the middle to the end of the standing estrus, i.e., 13-18 hours before evulation.
• Cows may conceive to AI at the beginning of estrus or 36 hours after the end of estrus but the conception rates are reduced.
• The correct timing of the AI is thus dependent upon true, accurate and early identification of estrus.
• A cow that is first seen in estrus in the afternoon or early morning is inseminated in the morning.
• A cow seen in estrus later in the morning, is inseminated in the afternoon of the same day.