Perumal, A. K. De, Jai Sunder and D. Bhattacharya

Animal Science Division

ICAR-Central Island Agricultural Research Institute

Port Blair, Andaman and Nicobar Islands


Reproduction plays an important role in the entire economy of a dairy farm and reproductive failure should be traced out from its source as rapidly as possible. This is only possible, when there is a clear understanding on which factors influence the fertility in dairy cows.

Fertility of a herd is best determined with the three criteria are adopted

(a) The pregnancy rate after the first insemination

(b) The number of inseminations per conception

(c) The average interval between parturition and conception.

Benefits of Artificial Insemination

(1).Improve the genetic quality of herd, (2). Positively impact the herd’s profit generation potential, (3). Increase consistency and value of the calf crop, (4). Access to superior and proven herd sires at an affordable price, (5). Eliminate need to purchase, house and feed breeding bulls, (6). Reduce labour and costs associated with convenience traits such as calving ability and (7). Shorten the breeding and calving season.

Factors influence the conception rate of dairy cow

- High body temperature in summer season causes reduced sexual activity, poor quality semen and poor conception rate.

- Age of female can influence first service and overall conception rates.

- Infections: Vibriosis, Trichomoniasis, Brucellosis, IBR virus, Leptospirosis, Bovine viral diarrhoea, Infectious pustular-vulvo-vaginitis, Mycoplasmosis and chlamydiasis cause infertility in dairy animal.

- Individual pathological changes:Urovagina, hydrosalpinx, adhesions and cystic ovarian disease leads to fertility.

- Genetic and anatomical abnormalities

- Climate: High temperatures and humidity result in less marked signs of oestrus and reduced conception rates.

- Season: In summer season, less obvious oestrus signs and less efficient oestrus detection, repeat breeders, drop in first service conception rate and overall conception rate

- Daylength: Cow is poly estrus animal and day length plays an important role in animal reproduction. Abnormal day length leads to abnormal reproduction in female and male animal.

- Size of the herd:Pregnancy rate decreased with the size of the herd. The repeat breeders are more common in the larger herds than in small herds.

- Housing system:Loose housings or loose housings with cubicles system will enhance oestrus signs intensity, activity of ovaries and easy detection of oestrus and conception rates.

- Choice of the bull: In dairy animal, 1:10 is good for better conception rate. Good libido, good quality semen and infection free bull increase the conception rate. Inbreeding should be avoided as this result in lower pregnancy rates.

- Hygiene at the time of calving:Improper hygiene at the time of calving leads to 5-10% lower pregnancy rates after first insemination and longer calving interval.

- Calving Difficulty:Increased calving difficulty will increase the length of the calving interval and decrease the overall conception rate.

- Interval between parturition and the first insemination:The interval should be 60-90 days for better conception rate and this will vary depending upon the abnormal parturition and other post partum complications.

- Detection of oestrus: Visible signs of oestrous are reddening and swelling of vulva, restlessness and mucus discharge from the vulva and standing heat.

- When to Breed: First heat occurs at 14 to 22 days after calving. Signs of heat are poor at first heat. Heat signs and conception rate improve until the third heat occurs at 50 to 60 days.

- Timing Insemination: Cows first seen in heat in the morning should be bred late in the afternoon. Those first seen in heat in the afternoon or evening should be bred the next morning.

- Nutrition and milk yield: The nutrition is frequently referred to as the cause of inadequate fertilityin dairy animal. The deficiencies and excesses of an unusually large number of feeds, minerals, trace elements and vitamins have been stressed.

- Forage or Plant Toxin: Certain plants, notably clovers, will contain high levels of estrogens which reduce the conception and fertility rate.

- Selection: Faulty selection of cows may give rise to a number of problems. Among these are gonadal hypoplasia, white heifer disease and cystic ovarian disease are more problematic.

- Culling cows: The cowswhich fail to become pregnant over prolonged periods should be culled and this decrease interval between parturition and conception as well as on the average number of inseminations per conception.

Signs of Heat

Standing to be mounted is considered the primary sign of heat. Most cows show increased sexual activity before oestrus or actual standing heat. Secondary heat signs indicating a cow is near oestrus include: alert, restless behaviour, bawling, shortened feeding time, aggressive behaviour, butting, swollen and reddened vulva, mucus discharge, withholding of milk, increased urination, mounting other cows, chin pressing on other cows, sniffing, licking of vulva and lip curling.

Good heat detection system

- Heat Detection should be in high priority and adopt a trained person

- Use a 21-day calendar or breeding wheel.

- Should know the signs of heat and difference between cows coming into heat and those in actual standing heat.

- Cows in tie stalls must be turned out at least once per day for heat detection.

- Schedule 2 to 3 daily heat observation periods with a minimum 20 minutes

- Ensure cows in loose housing have good footing and turning them outside for better heat signs.

- Use heat detection aids and prostaglandins wisely. They can be a valuable tool but do not replace a good program of routine heat detection by observation.

Preparation for insemination and sanitation

- Ensure that the cow to be bred is truly in heat. Research studies indicate between 7 and 20 percent of the cattle inseminated arenot in heat

- Restrain the cow first and thenthaw the semen. The restraint area should be familiar to the cow and free of stressful conditions. Unnecessary excitement may interfere with physiological mechanisms important to achieving a good conception rate.

- Develop good sanitary procedures and insemination practices. It is easier to learn good habits than to break bad habits.

Overall Management to improve the fertilityrate

- A suitable vaccination program

- Strategic worm control program

- Selection of male and female based on their ability to produce offspring

- If using natural mating, ensuring the correct proportion of male to female animals (1:10)

- Selecting animals suited to the environment

- Providing correct nutrition for the stage of production of the animals

- Selecting paddocks that minimize the detrimental effects of environmental