Method and apparatus for detecting standing heat in cattle

A method and apparatus for detecting standing heat in cattle includes an electronic timer module connected to a membrane switch. The module includes a digital time readout display, as well as audible and visible indicators. A saddle-like sleeve includes a transparent pocket having a sealable opening adapted to receive the timer module and membrane switch therein. The sleeve is adapted to be adhered to the base of the tail of a cow. The membrane switch is adapted to be actuated by the weight of other cows attempting to mount the cow when in heat. The switch actuates the timer, and also actuates intermittent operation of the audible and visible indicators to warn the cattle owner that the cow is in heat, and also to indicate exactly when the cow came into heat.

BACKGROUND OF THE INVENTION 
The following United States patents represent the closest known prior art, 
U.S. Pat. Nos.: 3,076,431; 3,158,133; 3,158,134; 3,205,857; 3,297,020; 
3,844,273; 3,948,249; 4,239,018; 4,247,758. 
Since the advent of artificial insemination techniques, it has been 
possible to breed cattle to optimize characteristics such as size, milk 
productivity, disease resistance, and the like. However, although 
artificial insemination no longer requires the presence of the breeding 
bull at the time of insemination, it still requires that the farmer or 
rancher determine the exact time of estrus of a cow, so that the 
insemination will fertilize the cow. The accurate detection estrus, or 
standing heat in cattle, is a problem long recognized but unsolved in the 
prior art. 
A cow comes into heat approximately every 21 days, and then remains in heat 
for approximately 10 to 12 hours. The cow then ovulates approximately 14 
hours after going out of heat. The time of ovulation is the optimum time 
for artificial insemination. If insemination is successful, the cow will 
be pregnant for 280 days. After calving, the ideal situation from the 
farmers standpoint is to reimpregnate the cow within 45 to 60 days after 
calving. 
However, if it is not known when the cow first entered heat, the timing of 
the artificial insemination must be approximate, and a significant number 
of inseminations will fail to produce pregnancy. The farmer must then wait 
for the next estrus period to again attempt insemination. It is reliably 
estimated that it cost a dairyman three dollars per day per cow if the cow 
is not pregnant when it could be pregnant. In an average size dairy herd 
of 400 cows, with an average calving interval of 14 months, accurate 
determination of standing heat could lower the calving interval to an 
average of 11.5 months. This savings of 45 days in the pregnancy cycle, 
multiplied by three dollars per day and by 400 cattle, can result in a net 
savings of $54,000 per year. Thus it is clear that the accurate 
determination of estrus onset in cattle is extremely important to 
dairymen, as well as other cattle breeders. 
One type of device known in the prior art for detecting standing heat 
employs a dye or dye forming chemicals disposed in a frangible pack and 
secured to the base of the tail of each cow in a herd. With the onset of 
estrus in any cow, the other cows will try to mount the one in heat, 
breaking the frangible pack and spreading the dye over the animal 
sufficiently to warn the cattleman that the cow has entered heat. However, 
if several cows enter heat on the same day, or if precipitation should 
wash away the dye, it is difficult to determine which cow is in heat. 
Furthermore, it cannot be determined to within 12-24 hours when estrus has 
begun, so that the timing of insemination involves too much guesswork and 
not enough certainty. 
Another approach known in the prior art employs a temperature sensor placed 
in the vagina of the cow, and includes a radio transmitter which emits a 
signal when the internal temperature rises. This temperature gain may 
indicate onset of estrus, or may also indicate a fever due to bovine 
illness. Also, experience has shown that many of these devices are lost by 
being expelled during urination by the cow. 
Other prior art attempts to detect estrus involve a radio transmitter 
strapped to the leg of each cow and coupled to a pedometer. The theory is 
that a cow entering heat will be more restless and will take more steps 
per day than a cow not in heat. The radio transmitter will emit a signal 
indicative of the number of steps and apprise the rancher each day. 
However, other factors may determine the number of steps per day, such as 
changes in grazing habits, the presence of other animals or humans, and 
the like. 
A significant failing of all of these methods and apparatus, in addition to 
the shortcomings noted already, is that they do not determine the exact 
time of onset of estrus, and thus cannot provide the cattle owner with 
accurate information for optimal timing of the artificial insemination. 
SUMMARY OF THE PRESENT INVENTION 
The present invention generally comprises a method and apparatus for 
accurately determining the time of onset of estrus in a cow, and for 
warning the cattle owner that the cow is in heat. Thus the timing of 
artificial insemination may be accurately determined to maximize the 
chance of impregnating the cow. 
The method and apparatus for detecting standing heat in cattle includes an 
electronic timer module connected to a membrane switch. The module 
includes a digital time readout display, as well as audible and visible 
indicators. A saddle-like sleeve is also provided, and includes a 
transparent pocket having a sealable opening adapted to receive the timer 
module and membrane switch therein. The sleeve is adapted to be adhered to 
the base of the tail of a cow, with the membrane switch disposed adjacent 
to the spine of the cow. The membrane switch is thus positioned to be 
actuated by the weight of other cows attempting to mount the cow when in 
heat. The switch actuates the timer, and also actuates intermittent 
operation of the audible and visible indicators to warn the cattle owner 
that the cow is in heat. The timer provides a count up function, so that 
the digital readout provides an accurate indication of the elapsed time 
from the onset of estrus. This information permits an educated 
determination of the proper time for insemination.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention generally comprises a method and apparatus for 
determining that a cow is in heat, and also for determining the time of 
onset of estrus of the cow with relatively high accuracy. 
With regard to FIG. 4, the electronic circuitry of the present invention 
includes a battery 11 connected to power a clock module 12, such as a 
digital timer module known in the prior art. The battery 11 is also 
connected to drive an audible signalling device 13 and visible signalling 
device 14, such as a light emitting diode. A membrane or tape switch 16 is 
connected between the battery and the clock module 12, and is adapted to 
actuate the clock module, as will be explained in the following 
description. The membrane switch 16 is also connected through the clock 
module to actuate the audible and visible signalling devices 13 and 14, 
respectively. The clock module 12 is configured as a count up timer to 
count elapsed time after actuation by the switch 16. A reset button 17 is 
also provided to reset the timer contents to zero, so that the device may 
be reused many times. 
In the preferred embodiment the clock module 12 comprises a customized gate 
array realized in a CMOS integrated circuit and produced by Accusplit, 
Inc, San Jose Calif. The membrane switch 16 comprises a laminated assembly 
of polyester material and conductive carbon ink, and is provided by the 
Xymox Division of the W.H. Brady Co., Milwaukee, Wis. It may be noted that 
other similar devices known in the art could be used by anyone having 
ordinary skill in the art. 
With regard to FIG. 1, the battery 11, clock module 12, signalling devices 
13 and 14, and the reset button 17 are all secured in a small modular 
housing 21. The housing 21 is generally disc-like in configuration, and 
includes a digital time display 22 on the upper end face thereof. The 
membrane switch 16 is joined to the modular housing 21 by means of a 
flexible flat cable connector 23, or the like. 
A salient feature of the present invention is the provision of a sleeve 25 
which is adapted to be secured to a cow. The sleeve is formed of flexible, 
durable plastic material, and includes a medial portion 26 and a pair of 
arms 27 and 28 extending therefrom in opposed, bilateral fashion. The 
sleeve includes a closed pocket 29 formed of transparent, flexible plastic 
material and extending from the medial portion 26 to the distal extent of 
the arm 27. The pocket includes a sealable opening 31 extending partially 
along the length of the arm 27. The opening is provided with a resealable 
fastener, such as a linear tongue and groove snap-acting seal, a hook and 
loop closure, or the like. The pocket 29 is dimensioned to receive the 
membrane switch 16 in an orientation generally transverse to the extent of 
the arms 27 and 28, with the housing 21 disposed in the distal end portion 
of the pocket. In the distal end portion of the pocket a plurality of vent 
holes 32 are formed to prevent moisture accumulation within the pocket, 
and to release any air pressure buildup within the pocket. More 
importantly, the vents 32 facilitate the transmission of the audible 
warning signal from the device 13 to the exterior of the pocket 29. 
The modular housing 21, the switch 16, and the connector 23 therebetween 
may be inserted in and removed from the pocket 29 by means of the opening 
31. As shown in FIG. 2, the housing and switch assembly easily may be 
inserted through the opening 31 and arranged within the pocket 29 in the 
configuration of FIG. 1. The flexiblity of the membrane switch and the 
connector 23 aid in arranging the components in the proper placement. 
To employ the apparatus of the present invention, the module 21, switch 16, 
and connector ribbon 23 are inserted into the pocket 29 of a sleeve 25, 
and the opening 31 is resealed. As shown in FIG. 3, the sleeve 25 is then 
secured to a cow with suitable adhesive. The sleeve 25 is disposed with 
the medial portion 26 extending over the spine of the cow directly 
adjacent to the base of the tail, with the arms 27 and 28 extending 
laterally therefrom. It should be noted that the membrane switch 16 is 
thus disposed directly adjacent to the rear spinal portion of the cow. 
With the onset of estrus in the cow, the common behavioral trait of other 
cows is to attempt to mount the cow in heat. As soon as the cow is mounted 
the first time, the placement of the switch 16 assures that the switch 
will be actuated, and the clock module 12 will be activated thereby. In 
addition, the audible and visible signalling devices 13 and 14 will also 
be activated intermittently by the clock module. When the herd is next 
surveyed by the rancher or owner, i.e., at the next milking session, the 
warning signals from the devices 13 and 14 will alert the rancher to the 
fact that the cow is in heat. The rancher can then read the timer display 
22 and ascertain how many hours have elapsed since the cow was first 
mounted, yielding an accurate determination of the time of onset of 
estrus. The rancher may then make an intelligent and informed decision as 
to the proper time for insemination of the cow. The clock module may also 
be reset to zero to deactivate the warning devices. 
After insemination, when the cow has been diagnosed as pregnant, the module 
21 and switch 16 may be removed from the pocket 29 of the sleeve 25 
secured to the cow, and reinserted in another sleeve 25. The new assembly 
is then ready to be adhered to another cow for further use.