The farm manager has the ability to control or manipulate the management of the farm,
Examples of how farmers control or manipulate these factors include:
•a suitable vaccination program
•strategic worm control program
•selection of both male and female animals on the basis of their ability to produce offspring
•if using natural matings, ensuring the correct proportion of male animals to female animals
•selecting animals suited to the environment
•providing correct nutrition for the stage of production of the animals
•selecting paddocks that minimise the detrimental effects of environmental factors for newly born animals
Effects of management on puberty:
With good nutritional management, most cattle reach puberty between 8 and 13 months of age. Failure to exhibit estrus beyond this time is called pre-pubertal anestrus.If delayed puberty occurs in a group of heifers of the same ages or a group of mixed ages then the problem is one of management.
Since, the onset of puberty is influenced by the available nutrition heifers of the same age that are fed a sub-optimal energy diet will show a prolonged pre-pubertal anestrus period.
Similarly, when a group of heifers of different ages are housed together and given a balanced ration, the larger or more aggressive herd mates will consume a greater portion of the available nutrition and tend to attain puberty at an earlier age while others may remain acyclic. However, in due course the entire population begins to cycle.
Poor management of peer group contacts may delay puberty in gilts
Puberty may be delayed by housing with young boars or by contact with old boars too early. As the expected time of first estrus approaches, inadequate boar contact or contact with board with low levels of boar odour may delay puberty.
Effects of management on estrous detection:
When animals are in estrus, mounting activity changes the color of the detector or erases the chalk or paint stick markings. With good management and proper interpretation, pressure-sensitive mount detectors provide excellent results.
In certain management situations various tricks can be used to improve estrus detection.
First, cows in heat can be left with the herd to stimulate activity. Studies have shown that mounting activity increased 3-to 5-fold when more than one cow was in heat. However, an argument for removing estrus cows is that animals who are actively mounting sometimes choose favorites. This can reduce the chances of detecting additional cows that are in the heat but less aggressive.
Second, questionable cows can be placed with strage animals to stimulate activity.
Third, simply moving cows as a group form one area to another, such as from concreate to a dirt lot, sometimes stimulates activity.
Heat checking should always include getting all cows up and moving them if they are in free stalls or outside. These tricks will not be feasible in all operations, but for those in which they can be used more heats may be accurately detected.
Pregnancy diagnosis in cattle:
A presumptive pregnancy diagnosis by cattle owners is based on history and clinical signs.
a) Exposure to a Bull or Artificial Insemination
History of a cow with a bull or the observation of mating or AI is not a reliable indicator of pregnancy status and may sometimes be deceptive. Reasons are
Even with high fertilization rates only about 50% of the inseminations result in detectable pregnancy.
Due to unobserved, unplanned, or unrecorded matings, many cows presented with a complaint of infertility are found to be pregnant on rectal palpation
b) Cessation of the Estrous Cycle
Around day 15 to 17 after ovulation, bovine embryos signal their presence as a result the corpus luteum is maintained, and the maternal estrous cycle is suspended. Thus, failure to return to estrus approximately 18 – 24 days after mating, suggests that conception has occurred.
Anestrum
It is possible that estrus signs are occurring but are not being observed which is purely a management problem.
MANAGERIAL CAUSES OF INFERTILITY:
Managerial deficiencies are a common cause for lowered infertility and repeat breeding in herds and must be differentiated from infectious form of infertility caused by Vibriosis and Trichomoniasis which are also herd problems.
The common managerial deficiencies leading to infertility are:
Poor heat detection
Improper time of insemination
Early embryonic death
Early Embryonic Death:
External factors involved in embryonic death include stress, nutrition, season of the year, climate, sire effects and transrectal palpation.
Maternal stress due to severe pain, malnutrition and transport has been implicated as a cause of EED.
Transporting pregnant mares for a distance of 300 miles (500 km) in less than 9 hours of traveling time can be stressful, but should not result in embryonic death. If a longer journey is necessary, the journey should be broken after 8 hours.
Waiting until the fifth week of pregnancy or later to transport brood mares may be advisable when critical events such as descent of the embryo into the uterus and transition from the yolk sac to the chorioallantoic placentation have occurred.
The common practice of transporting mares to stud for mating and returning home the same day should not be detrimental to their fertility, as long as the transport is safe and comfortable
Far from being avoided, regular exercise is important during pregnancy, although during the latter half, forced exercise should be decreased. Rectal palpation and ultrasound examinations should be considered safe procedures when performed correctly and there is no indication that ultrasound examination is detrimental to the embryo.
Contributor- Dr. Keshav
