Reproductive Management in Cattle

Study Notes

The cow must commence ovarian activity early in the postpartum period, show heat, conceive readily, carry the pregnancy successfully, and produce a calf.
The farmer must detect heat, mate the cow at the correct time, and provide adequate nutrition and other inputs.
The relative importance of these factors varies in different smallholder farming systems.
Under extensive free grazing conditions, nutritional fluctuations due to seasonal shortages in herbage cause delays in puberty and the postpartum cycle.
In tethered grazing or confined systems, factors such as heat detection, timing of mating or AI quality are more important.

Animal improvement involves developing or breeding animals with desirable characteristics such as good feed conversion, growth rate, disease resistance, and egg size.
It also involves upgrading existing breeds by incorporating genes for desirable characteristics.
This leads to the manipulation of characteristics like increasing the gene frequency of desirable genes in populations and removing or decreasing the frequency of genes responsible for undesirable characteristics.
This is done by bringing in high-quality breeds of livestock or semen with high productive capacity or other good characteristics.

At birth, many regions of the neonate skull have not yet been converted to bone, known as fontanels.
The neonate's skull changes shape to fit into the birth canal, sometimes causing a misshapen or elongated head, which usually returns to normal on its own within a few days or weeks.
Neonate genitalia are enlarged and reddened, with the male having an unusually large scrotum.
Females and even males may discharge milk from their nipples or a bloody or milky-like substance from the vagina, which is normal and will disappear with time.
The umbilical cord of the neonate is bluish-white in color and is usually cut after birth, leaving a 1-2 inch stub that will dry out, shrink, darken, and spontaneously fall off within about 3 weeks.

Once puberty has occurred, the female animal should have cyclical oestrous cycles and ovarian activity.
Aberrations in oestrous cycles include short oestrous cycles (intervals less than 17 days), which may be due to Follicular cysts.
Other aberrations include incorrect identification and recording of oestrus, and prolonged oestrous cycles (intervals longer than 24 days), which may be due to Luteal cysts or failure to detect oestrus.

There are three types of teasers used for oestrus detection: vasectomized bull, Pen-o-blocked bull, and Hormone-treated (testosterone or oestradiol) females.

Records are essential in assessing the potential of any breeding animal.
A form for recording sexual data should include tag number of the bull, date of collection, stimulus animal/location of situation, score or codified behavioural event, reaction time, ejaculate number, identity of semen collector, and a space for additional remarks.
Computer software can be used to collate, enter, check, analyze, and store vast amounts of data on animal production, reproduction, nutrition, health, and generate reports to aid management decision-making.