Fall ram purchases will have long-term implications on flocks
Decisions made with this fall’s ram purchases will have long-term implications on a producer’s flock.
Many traits can be selected for and against, in contrast to some flocks, in which the criteria may simply be the ability of that ram to breed ewes. Regardless of personal preferences, there are some “absolutes,” which, regardless of selection program and management scheme, need to be considered.
To begin, look at the fundamentals. The following might be a helpful reminder in the midst of ram sale season.
Teeth and eyes
Properly aligned teeth and good eyes cannot be compromised whether a producer is raising their own replacement rams or purchasing rams at a sale.
Proper alignment of teeth with the upper dental pad is important because it directly affects functionality and longevity on Wyoming’s challenging landscapes. Specifically, this relates to the friction, or “nip” force, between the lower teeth, or incisors, and the upper dental pad, which cuts plant material.
The inability to properly sever forage limits the ability of animals to consume adequate forage. Proper teeth-to-pad contact reduces the stress at the tooth root and will result in proper wear.
Incisors have to align with the upper dental pad.
Broadly speaking, the upper dental pad cannot extend beyond the lower incisors. This is known as parrot mouth. Nor can the lower teeth extend beyond the upper dental pad, known as bulldog mouth.
From professional observation, most parrot mouthed sheep are identified and culled. Yet, there is far too much tolerance for bottom teeth sliding above the upper dental pad.
Producers should slide a finger along the front of the teeth and dental pad, paying attention to the protrusion of either the teeth or dental pad, which helps prompt more visual observation.
Understanding the costs associated with developing rams and all other important criteria when selecting a ram. Yet, in instances where this ram is siring the next three or four years’ worth of replacement ewes and rams, taking the chance on a poorly aligned mouth is risky.
Visually examining eyes is another aspect that appears overlooked far too often.
Inverted lower eyelids, known as entropion, is the most common and highly heritable eye defect. This is most commonly identified shortly after birth, but from time to time is overlooked. Identifying and marking both the lamb with entropion and potentially the dam are critical, especially if producing breeding stock.
Weeping of eye fluids and staining below the eye are tell-tale signs of entropion problems. There are ways to remedy the problem in the young lamb with clips and sutures to get the lamb to market, but given the genetic component, breeding sheep with this problem need culled.
More emphasis on culling the ram should be considered if there is a greater incidence within a particular sire line. Failure to cull animals with this defect spreads the problems to potential buyers for generations. There needs to be zero tolerance with entropion eye lids.
Legs and feet
Research has concluded rams will travel two to five times more than ewes during breeding season, with eight to 38 services every 13 hours.
Proper structure of legs and feet is extremely important. This takes on slightly different meanings in different segments of the industry, commercial versus exhibition, but overall, it estimates the ability of rams to travel with ease to cover ewes.
Broadly speaking, determining proper structure requires observing the movement of a ram to identify discomfort in legs or restrictions in movement. Looking for proper flex in the knee and the correct tracking of the back legs can help to determine discomfort or limitations of movement.
Oftentimes, short, rapid steps can suggest stiffness or underlying discomfort and can serve to estimate the durability and longevity of a ram. Unfortunately, if a ram exhibits soreness and stiffness coming out of a dry-lot environment, it’s not going to improve in the breeding pasture.
A scoring system for each component of the leg and feet is helpful to select future replacement ewes and lamb.
In theory, this could entail a repeatable numerical scale system, based on visual similarities for a specific component in an animal.
The University of Wyoming has utilized a hybrid Australian system in some of our ram test evaluations with students. Specifically, we emphasize the front legs, back legs, pasterns and hock shape.
Breeding soundness exams
A larger scrotal circumference can be an initial screening tool and is highly correlated to sperm concentration and volume. A 20 to 30 percent increase in scrotal circumference from spring to fall is to be expected with greater increases expected for seasonal breeds.
For example, a recent study at Montana State University observed an eight-centimeter, 20-percent increase in scrotal circumference in Targhee rams from June to August.
Work done with range rams by Ruttle and Southward (1988) reported rams with a scrotal circumference of less than 30 centimeters were usually classified as unsatisfactory in their annual breeding soundness exams.
If rams don’t measure up in the late summer or early fall, they don’t measure up. Rams with a larger scrotal circumference, especially as ram lambs and yearlings, generally will sire earlier maturing, more reproductively efficient ewe lambs.
Components of a breeding soundness exam
There are several components of a breeding soundness exam.
The first is to palpate testicles for firmness, which should be similar to tone in a forearm when making a fist. The scrotum should be free of cuts or lesions. The testicles should be symmetrical with no swelling of the lower epididymis.
Second is an examination and palpation of prepuce for ulcers or scabs. Maintaining rams on a diet of less than 16 percent crude protein prior to breeding season will help prevent and remediate pizzle rot.
Deworming is warranted if rams were managed on irrigated or sub-irrigated pasture throughout summer.
Rams’ front teeth, the incisors, should align flush with the dental pad. Feel the upper molars through the cheek for excessive wear or abscesses.
Body condition score (BCS) of rams should be three to four on a scale of one to five. Stamina, libido and semen characteristics will decline in under-conditioned rams. Unadapted, excessively fat rams will also struggle with stamina, libido and thermal regulation of testis.
Fat rams sell well at ram sales, yet should be put on medium-quality grass hay after purchase to ensure rams are adapted to new environments prior to breeding season.
Testicular inflammation or an enlarged epididymis may point to infectious agents such as Brucella ovis. Consulting with an attending veterinarian can help delineate disease versus physical injury.
Begin semen evaluations at least two months in advance of the breeding season. Semen testing rams older than six years should be a priority as these generally show a decline in quality semen characteristics.
Formation of sperm, or spermatogenesis, lasts 50 days, with an additional 12-14 days required for the new sperm to travel through the epididymal duct. Six to eight weeks advanced planning will allow finding a suitable replacement ram if semen quality problems are identified.
Semen abnormalities, for example, low concentration, poor motility or poor morphology, may be attributable to a physiological challenge 50 days prior. This may include fever, nutrient deficiency, heat stress and/or shipping stress.
Semen testing too early in the summer, from May to June, especially in more seasonal European-type breeds, may indicate poor specimens when, in fact, these breed types should be retested closer to breeding season.
Semen testing twice within one day, especially for virgin rams, where feasible, or 10 days later, might determine if the abnormalities were from environmental factors or permanent infertility.
Also, consider some rams do not collect well as a result of the collection process and should be evaluated accordingly. Consulting with the attending veterinarian can provide additional cull or keep criteria and other abnormalities that might have been experienced during collection.
Ram sale considerations
What is clear when working with Wyoming sheep producers is they have subjective opinions on what type and kind of ram they like, which is great. What is less up for debate is all producers need to avoid the structural, teeth, eye and reproductive defects when buying and selling rams.
Rams sold at the Wyoming Ram Sale in Douglas on Sept. 15 are sifted to avoid many of these defects discussed. The quality of rams and friendship exchanged make the Wyoming Ram Sale a great experience every year. Regardless of this year’s lamb market, producers should look forward to looking through the pens and enjoying a visit with buyers and sellers in Douglas.
Whit Stewart is the University of Wyoming Extension sheep specialist. He can be reached at firstname.lastname@example.org.