One of the most practical sheep management tools during breeding season is the use of a ram marking harness. A ram marking harness is a small harness typically made of nylon or leather that holds a square colored crayon.
The way that a marking harness works, is that a colored crayon is attached to the front part of the harness and is centered over the ram’s brisket or chest area. When a ram with a properly fitted harness and with a temperature correct crayon mounts a ewe, the color from the crayon is transferred onto her rump.
By monitoring the backsides of any given group of sheep it is easy to determine which ewes have been bred. Most ewes will deliver approximately 145 – 149 days after ram service. A note on a calendar indicating the service day records the breeding and helps to calculate when a given ewe can be expected to lamb.
Marking harnesses are available in 2 or 3 sizes to accommodate the various breeds of sheep; and marking crayons are manufactured in differing degrees of hardness. Marking crayons are temperature sensitive and the proper crayon should be selected according the expected weather conditions during breeding season.
Hard crayons are used during hot weather for temperatures of 85°F and above. Medium crayons are for mild weather of 60°F – 85°F, and soft crayons are for use during cool weather breeding when temperatures are less than 60°F.
Marking crayons come in a several colors and are used in a few different ways.
One way is when 2 or more rams are working in a single group of ewes. When two rams are working together each ram wears a different color crayon marker on his harness. This system is most often employed for 50 or more ewes.
Another way that crayon marking is helpful is when space is very limited. By observing the backsides of ewes 4 or 5 times a day, a ewe can be removed from the group after she has been marked if necessary.
When ewes are run with two or more rams there’s no way to determine the sire of her lamb(s) if a ewe has been marked by two or more colors. With grade sheep it’s not a problem and the extra ram power is an advantage. But this method should never be used for registered sheep or when the offspring may need to be papered.
When using a marking harness it’s important to be able to distinguish between a “jump” smear and a good, solid breeding mark. Often a ram will attempt to mount a ewe who will not stand for him and he will leave a faint smear or streak of color on her backside or flank. When a ewe has been honestly bred by a ram wearing a marking harness the mark is quite distinct.
Different color crayons are helpful when trying to determine if ewes are pregnant or if ewes need to be re-bred or to determine if a ram is possibly sterile.
Most sheep are naturally polyestrous short-day breeders. Active estrus in a ewe lasts for approximately 24 – 36 hours and it is the only time that she will stand to be mounted by a ram.
Without human intervention like sponging, a ewe will begin a normal estrus cycle every 15 -17 days when daylight hours begin to decrease in the fall.
(sponging is a method of altering a ewes natural cycle by using hormones saturated on a tampon like sponge that is inserted vaginally for a few days and then removed)
By changing the crayon color on the harness every 16 – 18 days, it is possible to observe if a particular ram is re-breeding ewes. If he is re-breeding most of the ewes, he probably was temporarily sterile when he first was turned in with them. Some rams are very heat sensitive and can end up sterile or with a low sperm cell count for many weeks after a summer heat wave. Most heat sensitive rams will recover fully once the weather turns cooler. A ram can also be made temporarily less potent if he is asked to service too many ewes at one time. 30 – 35 ewes is about a much as a fully mature and experienced ram can handle.
There are many different reasons why a ewe may not get with lamb and settle after the first tupping (tupping is the term for copulation in sheep) and it’s not unusual for a ram to have to re-service a few perfectly normal ewes out of a large group during subsequent estrus cycles.
Back in the old days before there were marking harnesses and colored crayons, sheep breeders would paint the brisket of their rams daily with a mixture of linseed oil and different colored pigments or lamp black (soot).
It was a low tech and much messier way to record sheep breeding activity, but it sure enough got the job done.