i s a Figure 1. Map showing semen evaluation from all sections o: Texas. Area Satisfactory Questionable Cull — — — — — ——Percent——————— 90 6 4 _ _ _ t, B 78 18 4 33351-5 C 73 15 12 Areas B and C in the above map ‘ Qonlenld SURVEY CONDUCTED _____________________________ __ 3 How SEMEN Is COLLECTED __________________ u 4~ A REPEAT TEsT __________________________ __ 4 How SPERM Is EVALUATED _________________ __ 4 Density ______________________________ __ 4~ Motility ___________________________________ __ 5 Rate of Movement _____ __ 5 Morphology ______________________ __'______ 5 GRADES OF SEMEN __________________________ __ 5 Satisfactory Semen __________ _»_ ________ __ 5 Questionable Semen ___________________ __ 5 Cull Semen ___________________________ __ 6 REPRESENTATIVE SEMEN SAMPLE ___________ __ 6 CHECKING YOUNG BULLS ___________________ -_ 6 UsINo THE REsULTs OF THE TEsTs __________ __ 6 Satisfactory ____ __ ________________ _______ 6 Questionable __________________________ __ 6 Cull _________________________________ __ 6 WHEN To CHEcK FOR FERTILITY ___________ __ 6 Just Before the Breeding Season _________ __ 6 Soon After the Breeding Season __________ __ 7 Three to Five Months After the Breeding Season ____________ __ 7 WHo CAN CoLLEcT AND EVALUATE SEMEN _____ 7 OTHER PRACTICES T0 CoNsIDER 7 How much 0f a problem is the infertile bull - ur beef herds today? According to a re- I survey, approximately seven percent of the s in Texas are infertile. These bulls eat _' as much grass and cottonseed cake, drink it as much Water and represent just as much ncial investment as bulls doing a satis- ‘ ory job of settling cows. Some of them “p the fertile bull away from the cows that Vuld be bred which results in a smaller calf P- "For a long time producers have observed s» cows to see if they come in to heat again, I have checked calving percentages Within ‘ups of cows bred by one bull and have elim- ted the bull that failed to give a satisfac- g calf crop. This type of fertility testing is and expensive. It may mean losing an 're calf crop when a group of cows is run only one bull during a breeding season. also may mean that a long period elapses een the time a cow should calve and the 5 that she actually drops a calf. SURVEY CONDUCTED i: Approximately 2,000 bulls were tested for ility in a survey conducted by the Depart- ' tof Animal Husbandry in cooperation with e than 100 beef cattle producers at 33 Tex- jocations. Information was gathered on 1,369 these bulls. No attempt was made to se- bulls of certain breeds or ages. Various ~'ons of the State were visited when con- “ient and as many of the bulls were tested possible. 1.Table 1 shows the rating of the 1,369 bulls tttisfactory, questionable or cull. Satisfac- l indicates that the bulls should give serv- ;equal to the demands of the livestock pro- for obtaining a high calving percentage. tionable bulls are those that will settle be cows, but the conception rate may vary u 30 to 60 percent, thereby giving a very ,calving percentage. Cull indicates bulls are infertile as determined by the absence perm, dead sperm or possibly a few live It is commonlyi; assumed that the older a _, gets, the less valuable he is for reproduc- ' In examining this large number it was ' tively, extension animal husbandman, professor, associate 1- and extension animal husbandman, Department of , w Husbandry, The Texas A. & M. College System. TESTING BULLS FOR FERTILITY L. A. MADDOX. JR., R. O. BERRY. A. M. SORENSEN U. D. THOMPSON’ TABLE 1. EVALUATION OF 1.369 BULLS Rating Number Percent Satisfactory 1.141 84 Questionable 136 9 Cull ‘ s2 . 1 found that the percentage of cull bulls did not increase with age as much as expected. Table 2 gives a breakdown of the bulls by age groups. A grouping of the older bulls, 9 through 14 years, indicated that, from a reproductive standpoint, these bulls are as good potential reproducers as the younger bulls. These older bulls may have come from herds that had previously been culled because the producer would remove a par- ticular bull if his cows were not being settled. This method of culling may have cut down the percentage of poor bulls in the older age group. TABLE 2. EVALUATION ACCORDING TO AGE Years Number Satisfactory Questionable Cull "/0 7° % 1 685 82 12 6 2 276 88 6 6 3 116 80 10 10 4 109 _ 84 6 1U 5 36 81 13 6 6 48 84 8 8 7 41 73 17 10 8 40 96 4 0 9-14 18 83 ll 6 Av. 84 9 7 The bulls tested were classified into five breed and strain groups, as shown in Table 3. Most of them were Herefords. Both the Here- ford and Angus breeds showed a smaller per- centage of cull bulls than the Shorthorn. Fifty Shorthorn bulls were tested; 18 percent were classified as culls and 14 percent as question- able. Of the 52 Santa Gertrudis bulls tested, 6 percent were culland 31 percent questionable. In grouping all the bulls with some Brahman breeding, out of 72 bulls, 12 percent were cull and 27 percent questionable. Part of these high percentages may be due to the section of the State in which the bulls were located. Bulls were tested in every section of Texas, however, more were tested in some sections than in others.. Figure 1 shows the semen 3 TABLE 3. EVALUATION ACCORDING TO BREED AND STRAIN Number Breed Satisfactory Questionable Cull % 7o % 768 Hereford 87 7 6 390 Angus 89 7 4 52 S. Gertrudis 63 31 ' 6 5U Shorthorn 68 14 18 20 Brahman. Brangus. Beetmcrster (S cross- bred ’ 55 _20_ 25 Total 84 9 7 evaluation from different sections. The high- est percentage of cull bulls was found in East Texas and along the Gulf Coast to the Coastal Bend. This corresponds roughly with the area that receives 32 or more inches of rain annual- ly. In the extreme southern part of the State the percentage of cull bulls was lOW, but 18 percent had questionable semen. In the Pan- handle, West and Central Texas, 90 percent of the bulls had satisfactory semen and 10 percent questionable or cull. Whether differences in fertility are caused by climatic conditions, 0r whether the bulls themselves actually have a lower fertility potential in the eastern and Gulf Coast regions is questionable. Grasses and feedstuffs produced in the eastern and ex- treme southern parts of Texas are considered inferior to those produced in the central and western parts. A true explanation of the dif- ference in fertility is unknown. Bulls were tested during 9 of the 12 months, as shown in Table 4. This table also shows the number of bulls tested each month and their fertility ratings. No definite change in the fertility pattern is evident as a result of climatic conditions. Most livestock producers believe that their bulls have lowest fertility during the. late summer, but this seasonal dif- ference is not shown b-y the survey. However, there is a trend toward lower fertility in late summer if the questionable bulls are included with the cull bulls. TABLE 4. EVALUATION ACCORDING TO TIME OF TEST Month Number Satisfactory Questionable Cull % % 7° Ian. 136 87 5 8 Feb. 83 77 15 8 Mar. 239 92 4 4 Apr. . . . . . . . May 37 70 8 22 lune . . . . . . . . Iuly . . . . . . . . Aug. 10 60 40 0 Sept. 149 59 25 16 Oct. 376 86 9 5 Nov. 53 49 36 15 Dec. 286 93 4 3 Av. 84 9 7 4 HOW SEMEN IS COLLECTED Semen has been collected for evaluation and artificial insemination for many years, but th methods used have been impractical for rang bulls. The electro-ejaculator has overcome many of the difficulties experienced with the other methods of collection. If a bul is restrained properly "int a good chute semen may be collected with this machine, r. gardless of the bull’s disposition. If a ranch man works his bulls routinely through a chu once a year, the semen sample can be collect, at that time and little additional handling W be required. Bulls on small farms can b hauled to one central location where there ar proper pens and chutes for testing. Collectin and evaluating semen requires only 6 to 1 minutes per bull. The electro-ejaculator was developed I. produce an electrical impulse to stimulate th nervous system supplying the reproductiv“ tract, causing erection and ejaculation. Low power stimulations given intermittently shoul be used to initiate response. The power shoul be increased gradually to obtain extension f, erection prior to ejaculation. The first flui that passes is a clear, watery secretion fro_ the accessory glands which contains few ' any sperm cells. Following this, the ejaculat turns into a milky fluid consisting of spe I and accessory fluids. A collection is made a this time for evaluation. The collection ~< made in a test tube attached to a flexible plasti funnel which reduces breakage and injury, The reproductive organs should be examine for abnormalities at the time of testing. A REPEAT TEST If a bull is found to be in the questionab a or cull group, a repeat test should be mad while he is still in the chute. Even a third an fourth ejaculate may be necessary in a few in stances when the operator is not sure that h has obtained a representative sample from f particular bull. A few minutes should be lowed for the bull to regain his composure b‘ fore restimulation occurs. I HOW SEMEN IS EVALUATED The semen sample is examined with th naked eye and under a microscope to determin four characteristics—density, motility, rate 0 movement and morphology. Density The first characteristic observed is th color. Samples more concentrated with spe u will be milky to creamy white. Samples tha ' range in color from slightly milky to a clear watery secretion contain fewer sperm cells. ‘ Figure 2. Essential equipment for collecting and evaluating semen. Motility The semen sample is examined next under a microscope for motility or the percentage of moving cells. Semen samples usually will have 50 to 70 percent motility, or that percentage of moving cells. Bear in mind that dead cells may be bumped by moving live cells and cause an apparently higher percentage of motility than actually exists. Rate of Movement Rate of movement is the third character- istic. Rapid forward movement is desirable. Morphology The fourth characteristic is morphology, or the appearance of abnormal sperm. Normal sperm are much like a tadpole with a long tail, as shown in Figure 4. Many types of abnor- malities may appear, including coiled or crooked tails, tailless, broken necks and small, large or double heads. Some of these are shown in Figure 5. GRADES OF SEMEN Semen samples usually are graded as satis- factory, questionable or call. Satisfactory satisfactory semen sample should have . good density as indicated by an opaque, milky a white ejaculate. Microscopic examination should show that the milky appearance is i? caused by sperm cells and not by foreign ma- terial such as leucocytes due to infection. More than 5O percent of the sperm cells should be g moving. Generally, a good sample will have . 50 to 70 percent rapidly moving cells. Close observation is needed to determine abnormali- ties, which should be less than 15 percent. Questionable Questionable semen has a single or combina- tion of low values for density, motility, rate of movement or morphology. These may in- clude fair density, as denoted by a translucent Figure 3. Sample No. l. creamy white in color. indicating good density; sample No. 2. watery and contains only a few sperm cells. Figure 4. A microscopic picture of good-quality sperm cells. or slightly milky ejaculate, motility of 30 to 50 percent, medium rate of movement and ab- normalities above 25 percent. If the sample is within the ranges given in any of the four criteria, it should be graded questionable. Cull A clear, watery sample indicates cull semen. Such a sample will show few, if any, sperm cells under the microscope. The sample is cull if all of the sperm cells are dead, or if they show only a slight rate of movement. Abnor- malities alone usually are not enough to cause a sample to be graded cull. REPRESENTATIVE SEMEN SAMPLE A representative sample of semen must be collected for proper evaluation. Occasionally a bull will not respond to the electro-ejaculator satisfactorily and may produce better semen than the test indicates. Where rechecks were made 1 month later, only one out of every 30 bulls classed as questionable or cull im- proved enough that the semen could be classed as satisfactory. CHECKING YOUNG BULLS Evaluating the semen of young bulls should be encouraged, but certain facts should be con- sidered. Semen production begins with sexual maturity and all bulls do not reach maturity at the same age. Most bulls of European breeds show viable semen as early as 14 months of age. Semen evaluation in bulls of other breeds usually is not recommended until around 18 months of age. Semen samples from young bulls will have less volume and lower density than from older bulls. 6 Figure 5. A microscopic picture of sperm with numerous!» deformed cells. ‘ USING THE RESULTS QF TESTS Satisfactory A bull that produces satisfactory semen andl is able to mate properly, is capable of settling- most of the cows to which he is bred. . Questionable Bulls showing questionable semen are no l. sterile, but will settle about one-fourth to on » half of the cows to which they are bred. Suck bulls should be culled or retested after 30 days Only under extreme circumstances Where at expensive bull is involved or replacements can not be obtained, should questionable bulls b kept. In most instances, these bulls should o removed from the breeding herd. In som. cases, veterinarians can determine the causi of low fertility in bulls and treat them succes fully. Cost, time and the response to trea J ment will vary with the cause of low fertility" Cull Bulls classified asculls may occasionall cause a cow to conceive. But when the seme contains no sperm or all the sperm are deaf the bull cannot cause a cow to conceive. Bul that produce cull semen should be disposed 0 or treatment startedas soon as possible. = WHEN TO CHECK FOR FERTILITY 1 Three periods during the year, dependii on the ranchman’s situation, are the most pra tical for checking bulls for fertility. * lust Before the Breeding Season The best time to “find out about the fertili of bulls is just before the breeding seaso f starts. By testing at this time, ranchmen can identify sterile or near-sterile bulls at the time ; they are expected to settle cows. A small per- centage of the sterile or near-sterile bulls, as " Well as those with low-quality semen, may re- ;’ cover; but since this takes 3 to 6 months, they are of little value during the current breeding ‘ieason. The main disadvantage in checking at this i i time is that the ranchman has little time t0 buy replacement bulls and those available probably have been picked over. v h Soon After the Breeding Season . Semen collected.at the end of the breeding 1 season should be evaluated carefully because ‘ heavy service temporarily lowers the semen i quality in most bulls. Bulls with low-quality semen may have been the most active during % the breeding season. In a few places where } calf crop precentages are low and extreme weather conditions may be a factor, checking after the breeding season may be advisable. i: Such checks can be profitable because of the savings in feed costs if the bull is sold at that time rather than 6 to 9 months later. i Three to Five Months After f the Breeding Season q It may be more practical on some large ranches to identify infertile bulls about the {time the calves are weaned. These bulls may be heavier at this time and sell for more money 7nd the ranchman has a few months in which - ~ buy replacements. WHO CAN COLLECT AND EVALUATE SEMEN Fertility testing may be conducted by any individual trained and equipped in semen col- lection and evaluation. Short courses are conducted annually for veterinarians from various parts of the State at Texas A. & M. College in the use of the electro-ejaculator and the evaluation of semen. A growing number of Texas veterinarians have been trained, have obtained the necessary equipment and are collecting and evaluating semen. . Many of the larger ranchmen have obtained the equipment for evaluating semen and have had their own technicians trained to conduct fertility tests. Another plan is through a co- operative group of producers who have a trained technician test all of their bulls. In this way the cost of the equipment is shared. OTHER PRACTICES TO CONSIDER The whole purpose of fertility testing in bulls is to produce more calves in the most profitable season, thereby increasing the re- turn to the producer. Fertility testing of bulls is best supplemented by palpation of cows to determine pregnancy and by a disease control program, particularly those affecting repro- duction. These three programs Work together for the beef cattle producer. Through them, Lie gan improve the breeding efficiency in his er . Location oi iield research units oi the Texas Agricultural Experiment Station and cooperating agencies ORGANIZATION OPERATION IN THE MAIN STATION, with headquarters at College Station, are 16 su matter departments, 2 service departments, 3 regulatory services an administrative staii. Located out in the major agricultural areas oi Texi 21 substations and 9 field laboratories. In addition, there are 14- coop j stations owned by other agencies. Cooperating agencies include the_ Forest Service, Game and Fish Commission of Texas, Texas Prison 7 U. S. De artment of Agriculture, University of Texas, Texas Technol » College, Texas College oi Arts and Industries and the King Ranch. v experiments are conducted on iarms and ranches and in rural homesfj THE TEXAS STATION is conducting about 400 active research projects, grid in 25 programs, which include all phases oi agriculture in Texas. A these are: Conservation and improvement oi soil Conservation and use of water Grasses and legumes Grain crops Cotton and other fiber crops Vegetable crops Citrus and other subtropical fruits Fruits and nuts Oil seed crops Ornamental plants Brush and weeds Insects Two additional programs are maintenance and upkeep, and central sea Research results are carried to Texas farmers, ranchmen and homemakers by county agents and specialists of the Texas Agricultural Ex- tension Service jOJCLy ,6 WQJQGJCL .94 jomorrow ,6 Iflgfédd State-wide Research b‘: “,1 "k The Texas Agricultural Experiment Static» is the public agricultural research agen i’ oi the State oi Texas. and is one oi tel parts oi the Texas A8=M College Systej Beef cattle Dairy cattle Sheep and goats Swine Chickens and turkeys Animal diseases and parasit Fish and game j Farm and ranch engineering Farm and ranch business / 4 Marketing agricultural prod y Rural home economics A Rural agricultural economi _ Plant diseases I AGRICULTURAL RESEARCH seeks the WHATS. the r WHYS, the WHENS, the WHERES and the HOWS oi v hundreds oi problems which confront operators oi farms z and ranches, and the many industries depending on or serving agriculture. Workers oi the Main Station I and the iield units oi the Texas Agricultural Experiment i Station seek diligently to iind solutions to these Q problems. . Texas Agricultural Experiment Station, R. D. Lewis, Director, College Station, Texas