Agriculture Reference
In-Depth Information
10.9
Technology to predict and supervise farrowings
10.9.1
Physiological signs of imminent farrowing
Other than behavioural signs, many clinical signs give clear indications of impending
farrowing. Several studies have demonstrated that the sow's body temperature gradually
rises to 1-1.5 °C higher than its normal body temperature, from 24-48 h before the onset
of farrowing until 12 h before farrowing. This increased body temperature is seen until
weaning (Elmore
et al.
, 1979; King
et al.,
1972). Detection of the sow body temperature
is a reliable and fast way would be of help in predicting the onset of farrowing, but
also in detecting upcoming diseases which can occur at farrowing and early lactation,
such as PDS. However, the traditional rectal temperature detection is not practical. A
remote detection method would save time and reduce stress on the animals. Recent
studies showed that body surface temperature in swine at various anatomical sites (eye,
mammary gland, back of the ear, vulva, and inner part of the ear) can be measured with
an infrared camera (IRC) and concluded that infrared thermography may allow routine
measurements of body surface temperatures that can be used for early disease detection
(Schmidt
et al.
, 2013; Traulsen
et al.
, 2010). Single-time measurements of body-surface
temperature with IRC cannot deliver reproducible results under field conditions, but
implementing an adapted computer program would improve its use by practitioners as
a monitoring tool. For example, IRC monitoring of sow body temperatures over 1 week
before farrowing would provide average temperatures for individual sows (Schmidt
et
al.,
2013). In this way either the physiological rise of temperature before parturition or
an abnormal rise during farrowing or early lactation could be detected and used to alert
farmers of impending farrowing or disease onset.
The respiratory and heart rates also rise a few hours before farrowing, returning to
normal after parturition (Kelley and Curtis, 1978). Other well-known signs of impending
farrowing are the presence of milk in the udder and a swollen vulva. As described
previously, nest-building behaviour is also a very good predictor of upcoming parturition.
A few hours before farrowing, the sow's normal activity level can increase three-fold
(Hartsock
et al.
, 1997). Observing changes in these signs helps to predict the onset of
farrowing in sows, but a more precise collection of data, with the help of technological
devices, for example, could provide more accurate predictions.
10.9.2
Predicting the onset of farrowing using movement sensors
The use of a photocell sensor placed at a height of 0.6 m in farrowing crates, makes
it possible to detect when the sow is standing up. The average duration of standing is
longer in the 24-h interval prior to farrowing compared with all the other 24-h intervals
from -120 h until +72 h, relative to farrowing. The mean frequency of standing up and
lying down movements is also greater in the 24-h interval prior to farrowing compared
with these other intervals (Figure 10.10). Similar findings can be obtained if a force
sensor is placed on the floor under the sow. The force sensor recorded a greater number
of peaks (activity) in the 24-h interval prior to farrowing than in all the other 24-h
intervals monitored.
