The use of artificial insemination as a primary reproduction technique obviously makes it necessary to identify the animals on heat. The use of synchronization makes artificial insemination easier in as much that insemination is carried out at fixed times. However it cannot be used on all the animals throughout the year.
In the buffalo farm in Italy the identification of females on heat is not usually part of the official duties of the herdsmen. Since artificial insemination is not routinely used, readings taken are used only to add to the anamnesis of the individual animal and to give extra data to the veterinary expert or, in some cases, to ascertain the paternity of a calf. It is difficult to persuade the staff to perform a task that is different from the duties normally required. Moreover it is difficult to recognise the animals by simply looking at them. Their coats are a uniform colour. The identification tags applied to the buffalo are often impossible to read on account of encrusted mud.
It has already been noted that female buffalo do not ostensibly manifest reciprocal covering postures. One means of identifying animals on heat is to use a vasectomized bull. This has a dual function. Firstly to identify the animals on heat and secondly to improve the reproductive efficiency of the herd thanks to the “bull effect” (51) on female buffaloes which has already been described. In the last few years our Research Unit has been investigating the possibility of adopting pedometers for use on farms.
The need to develop new technologies to identify animals on heat stems from the dairy cattle industry where the problem of synchronizing artificial insemination and the oestrous cycle is all the more pressing and where the success in the identification of fertile periods is reported to be still around 50%. The first observation that the walking activity of female mammals increases at the onset of the oestrous phase in the sexual cycle was eighty years ago. Later studies showed that the onset of the oestrous phase differed from that of all the other phases in the cycle. Pedometers are instruments which measure the number of steps taken in a given time. The data can then be processed in relation to the motor activity of the animal in the preceding days and expressed as a percentage of a sample period (8 – 10 days). A computer is able to trigger a series of signals when motor activity exceeds the average recorded for the previous days by a certain percentage, indicating that the animal is now on heat.
Pedometers were installed experimentally on a buffalo farm of 250 adults. They proved to be a useful accessory in artificial insemination in cases of spontaneous heat and provided useful information concerning their potential for further use
The average length of the heat period registered by the pedometers was about 17 hours with small variations according to the month of the year. Covering by the bull, when present, occurred, on average, about eight hours after the first signal from the pedometer. Ovulation occurred on average 24.4 hours after the first signal of heat from the pedometer. However, ovulation also took place earlier in buffaloes for which there had been only one signal from the pedometer than for those which had two or more signals. 9.8 % of the cases of the onset of heat signalled by the pedometer and confirmed by gynaecological examination were accompanied by high readings of progesterone (> 1.5 ng/ml in the blood). Almost 11 % of these signals came from subjects that were already pregnant; of these 17.6 % were confirmed to be on heat by clinical examination
Sensitivity in the signalling of the onset of heat ranged from 85-98 % and accuracy was 75 %. These readings tally with those recorded for dairy cows. The system examined showed an increase in sensitivity of over 90 % when considered in association with the signals provided by the vasectomized bull and herdsmen
