LINEAR MEASURING GUIDELINES & CORRELATIONS FOR THE MALES
1. The top line is the total length of the animal from front of pool to back of rump. The top line is taken for three measurements, Neck length, Body length and Rump length. These three measurements make up the total top line length.
TRUE, TOTAl TOP LINE FOR BULLS ONLY
2. Total top line or true top =
2/3 top line X 1.5 (.5, 1.0, 1.5).
Example: If the bull was 70 inches long and his 2/3 is 48, his neck lengthwould be 22 inches long. (70 inches – 48 inches = 22 inches).
Multiplying by 1.5 (1.5 X 48 =72) you get the true top.
3. The total distance aroundof the animals heart girth. The girth should be equal to the total top line or larger at 12 months of age. The large girth is needed for proper size for vital organs (heart, lungs, and glands). The closer the heart girth is to the top line, the more efficient, adaptable and vigorous the animal is. If heart girth is larger than top line it is a plus. Insufficient heart is a high indicator of structural defects, allows front feet to toe out, hooked toe, more susceptible to stress and is a high maintenance animal. They do not perform well on grass. Reproduction suffers. Small heart girth is a structural defect and should not be tolerated.
ADJUSTED NECK LENGTH
4. Actual neck length minus half the body length (24 –22 = -2). The higher the levels of testosterone, the more crest development, the shorter the neck.
- Short necks are a good indicator of libido and high testosterone.
- The cervical vertebrates have a tendency to curve up, making the neck shorter.
- Short necks indicate a larger scrotal therefore a higher level of hormones.
- Short necks indicate wider shoulders (male characteristics).
- Bulls with a neck longer than 2 inches at 12 months lack male hormones, resulting in late maturing daughters, reaching puberty later in life and tend to be slow breeders.
- Long necks are structural defects, no genetic progress can be made with these bulls. They will be high maintenance bulls.
- Bulls with long necks have a smaller scrotum.
- Bulls with shorter necks sire daughters with wider rumps.
- Bulls with short necks sire daughters that mature early.
BODY LENGTH OR 2/3 TOP LINE
5. The 2/3 top line is composed of the rump length and back length. Distance from the middle dip in the vertebrate (chine bone) between the shoulder blades to back of rump. If the back is too long it affects the neck length and the animal is out of balance. Long backs tend to be weak and will sway. Most long backs have too small a loin muscle. The long backed animals will have a dip from loin to top of the shoulder. There will be a dip from rib cage to shoulder blade. These breaks or dips are structural defects and should not be tolerated.
RUMP LENGTH PERCENT
6. The rump length percent is the percentage the rump makes up of the body length or 2/3 body length. Divide the 2/3 body length into the rump length. Rump length percent in the bull influences the neck length in his daughters. Less than 40% rump length in the bull increases the neck length of his daughters and makes for a smaller heart girth, thus higher maintenance. A long neck in females is not symbolic of femininity. A range of 38% to 40% is ideal, less than or more than is in the extreme. This range works best and will make adequate milkingdaughters. The rump length percent sets the standard for the degree of masculinity in the bull. If the rump length is below the 38% level, the standard for masculinity is much lower. The low standard does not create rugged bulls and in most cases the scrotal is less than 38 centimeters at 12 months.
7. Divide the rump height into the rump width = rump width percent. This number should be 44% or greater. Greater is better. (Example- 24 rw. by 50 rh = 48% rmp. Wdth%). High rump width percent is indicative of early maturity and ease of keeping. Bulls with higher rump width percent usually have wide shoulders, deep chest and a more acceptable scrotal. With good rump width% the animal normally has a better chest & shoulder area.
ADJUSTED SHOULDER WIDTH
8. Shoulder width minus rump length. Adjusted shoulder width in bulls should be +2 inches or greater at 12 months of age. Greater is better. Wide shoulders makes room for vital organs (heart & lungs). Masculinity is responsible for:
- Highest indicator of reproductive efficiency.
- Ability to withstand stress.
- Sire sons when mated to proper phenotype cows (feminine) that make herd sires.
- Sire daughters that reach puberty early,breed back and wean a heavy calf.
- Yearling bulls with good adjusted shoulder widths correlates with uniform
- Gestation time and length, uniform birth weights, ease of calving and more uniform weaning weights. Wide shoulders usually means a larger scrotum.
- Masculinity in the bull is in the wide, deep shoulders and short neck with a rump to match the front.
- Masculinity sires more pounds of beef. In the bull the rump should balance with the shoulders.
9. Correlates highly with gain-ability. Extremely tall animals tend to be out of balance due to slow puberty development, which lowers reproductive efficiency.
- Taller animals have less meat on their carcass than the shorter thicker animals.
- Taller animals will tend to have a smaller chest and shoulders and are easy to stress and are a higher maintenance animal.
- Taller animals do not do as well on grass and takes longer to finish.
- Tall animals require more high energy.
- A frame score from 4.5 to 5.5 tends to work best for finishing on grass.
10. The flank circumference should be 0 with heart girth to 2 inches larger than heart girth.Small flank measurement is indicative of absence of meat on rump. The same will be passed on to the progeny.
11. Thurl should be 13% of the rump height or greater. Greater is better if the slopes of the rump is of the proper angle.
- Thurl size and shape makes for ease of calving.
- Indicates pelvic depth and structural soundness of hind legs.
- If the thurl is properly in place the animal will track (back foot in front track) measurement is taken from ground to stifle joint to top of back.
12. The scrotum of yearling bulls should be 38 to 40 centimeters. Larger or smaller is in the extreme and should not be tolerated. The scrotum should be football shapedwith the epididymis on the very bottom of testicle. If the epididymis is anywhere else but on bottom, theresults shows up in the quality of udder of thedaughters. The sons will have the same problem as the sire or worse with irregular shaped testicles (recessive genes). If the nipples of the sire are on the neck of the scrotal sack the daughters udders will be tilted up in font and lower milk production. If the nipples of the sire are on the scrotal neck his sons will have a large navel area with the openingpointing toward the ground and fertility is lower. Irregular shaped testicle and epididymis causes irregular and cylinder shaped udders, large nipples and causes udders to sag and break down.
IMPORTANT AREAS OF THE MALE
13. Shoulder width.
Heart girth to top line.