Question 1: What is meant by the term metoestrus bleeding?
We talk about metoestrus bleeding when patches and strings of blood are present in the vaginal mucus staining the tail perineum just after or even during the standing heat. The phenomenon occurs in approx. 90% of heifers and not more than 45% of cows.
The presence of blood in the mucus is not an indication of conception or a failure to conceive. The metoestrus bleeding should be distinguished from the presence of blood associated with traumatisation of cervix caused by inappropriate AI technique.
Question 3:What should I do if during the rectal examination the preovulatory follicle ruptures?
With proper technique of rectal examination applied only real “ripe” ovulatory follicle may rupture. In such a situation AI should be performed within 24 h. It is important always to relate such event to the behaviour of a cow to be sure that the animal is in oestrus.
Question 4: When can I decide that the heifer suffers from a delayed puberty?
There are certain age frames considered as norms for puberty attainment in cattle. See Physiology section. Nonetheless it is important to remember that it is not only the age but also the body weight that determine sexual puberty.
In general a heifer of dairy breeds not seen in heat after she reached 14 months is considered as suffering from delayed puberty. The same will apply to beef heifers older than 16 months.
In zebu breeds because of great variability between breeds and climatic conditions apart from literature quoted norms the average age at puberty for a given herd should be considered when assessing an individual heifer.
Twinning is a physiological phenomenon that rarely (below 1% of population) occurs in cattle. Nonetheless there has been an increased frequency of twinning observed recently in dairy cows.
Factors proposed as predisposing dairy cows to double ovulation:
The standing heat reflects the standing reflex – the cow in the peak of oestrus allows for being mounted and mated by the bull. Therefore it is the cow that allows to be mounted that is in the standing heat.
Question 7: When can I expect the signs of pregnancy loss or abortion to be visible?
In general early embryonic loss often goes undetected as the embryo dies and is resorbed by endometrium. Normally when embryonic death occurs before 16d post AI no changes in oestrus cycle are observed and cows come back to heat as if they did not conceive. With the embryo dying after d16 post AI usually a delayed return to heat is observed (28-35d post AI).
Late embryonic loss (35-42d post AI) and foetal loss (from 42d onward) can be detected when dead embryo/foetus and foetal membranes are expelled through the vagina.
It is important to remember that chances for detection of early foetal loss decrease in pasture where animals move freely and various carnivores can have an easy access to the aborted tissues.
Question 8: How often should heat observation take place to be most efficient?
To achieve high efficacy of visual heat detection the observation should take place 3-4 times a day by the same person.