False Mounts Research Articles

Effects of sexual preparation on sperm output, semen characteristics and sexual activity of beef bulls with a comparison to dairy bulls.

Two trials were conducted with Angus and Hereford bulls to determine the effects of sexual preparation by false mounting upon sperm output, semen traits and sexual activity. Two successive ejaculates were collected by artificial vagina on 1 or 2 days per week and either three false mounts (3FM) or none (0FM) preceded each ejaculation. The data were compared to data for Holstein bulls collected twice in succession on 1 day per week after either 3FM or one false mount (control). Use of three false mounts effectively increased (P<.01) the number of sperm obtained in first ejaculates from beef and dairy bulls and in second ejaculates from dairy (P<.05) but not beef bulls. The higher sperm numbers in first ejaculates after false mounting reflected significant (P<.01) improvements in both sperm concentration and semen volume. For second ejaculates, semen volume was greater (P<.01) with 3FM only for dairy bulls; sperm concentration was lower (P<.05) for beef after 3FM than after 0FM and not different for dairy bulls. A third trial with Angus bulls tested all combinations of OFM and 3FM for first and second ejaculations collected 2 days weekly. The total number of sperm in second ejaculates from beef bulls was improved(P.01) by false mounting. for obtaining sperm output data from beef bulls to be used as an index of sperm production, 3FM might preced each ejaculation.For commercial bulls studs, however, this third trial with Angus showed that use of 3Fm before both first and second ejaculates (3FM-3FM) did not enable collection of significantly more sperm in two successive ejaculates (15.1 × 10 sperm) than a combination of 3FM-0FM (13.4 × 10 sperm).It required 35% less time (P.05) to collect about the same number of sperm in two ejaculates with 3FM-0FM (29.8 min.) as with 3FM-3FM (46.0 min.) It is concluded that a combination of three false mounts before firts and no false mounts before second ejaculates is practical for increasing sperm output of beef bulls used in commercial artificial insemination.

Serum levels of LH, prolactin and growth hormone after ejaculation in bulls.

Six young (1.5-2.5 yr)and six mature (3-6 yr) bulls were ejaculated once weekly for 4 weeks. Two ejacula were taken after three or four falsemounts and two were taken during the first mount (no false mounts). Sera prepared from tail vein blood collected 30 mm before and 5 and 30 mm after each ejaculation were assayed for prolactin, luteinizing hormone (LH), and growth hormone (GH). Sexual preparation increased (p < .01) seminal volume and totalsperm per ejaculum. Before ejaculation, levels of serum prolactin averaged 10.8 ng/ml. Serum prolactin increased (p < .01) to 59.0ng/ml 5 mm after ejaculation and decreased to 38.3 ng/ml 30 mm afterejaculation.Levels of LH, which averaged 1.18,1.33,and 1.05ng/ml in samples taken at comparable intervals,did not differsignificantly.Growth hormone increased (p < .01)from 4.1 ng/ml before ejaculationto 8.1 ng/ml 5 mm after ejaculationand returned to pre-ejaculationvalues by 30 mm afterejaculation.Neither age nor sexual preparation affectedlevelsof prolactinor LH. In contrast,GH was higher (p < .01) in older than in younger bulls, and higher (p < .01) aftersexual preparation. We conclude that stimuli associated with ejaculation cause release of GH and prolactin, and possibly LH, but prolactin is released in greater quantity than LH or GH.

Semen output of rabbits ejaculated after varying sexual preparation.

SummaryThree intensities of sexual preparation were compared with none using 9 rabbits which each furnished 2 ejaculations every second day for 38 days. The average sperm content of first ejaculations after one false mount (102.9 × 106) was 178% greater than that following no sexual preparation (37.0 × 106) and 3 false mounts resulted in an additional 40% increment in sperm output over one false mount. Sexual preparation also increased average sperm content of second ejaculations, although the increments were not as large as those obtained in first ejaculations. Analyses of seminal volume and total fructose content revealed that sexual preparation stimuli also affected accessory glands, but the magnitude of effect was proportionately smaller than the magnitude of the effect on epididymides. Sexual preparation also reduced the relative magnitude of the within-buck variance of total sperm output.

Sperm Output of Dairy Bulls with Varying Degrees of Sexual Preparation

Summary The sperm output value of false mounting relative to other sexual preparation stimuli was assessed by ejaculating 151 mature dairy bulls weekly for ten consecutive weeks after imposition of zero, one, two, or three false mounts during a planned duration of 0, 5, or 10 min of active sexual preparation. The average values for motile sperm per ejaculate obtained from the bulls with a planned duration of 0 min were 4.95, 8.35, 10.12, and 9.84 billion for zero, one, two, and three false mounts, respectively. The comparable averages for the bulls with a planned duration of 5 min were 10.22, 10.14, 10.99, and 12.66, respectively; and for the bulls with a planned duration of 10 min were 11.61, 12.35, 10.94, and 14.31, respectively. The averages of 8.32, 11.00, and 12.30 billion motile sperm for 0, 5, and 10 min of preparation, respectively, differed significantly (P The evidence supports the contention that the various sexual preparation stimuli are additive and that they conform to Fechner's Law.

Libido, Sperm Characteristics, Sperm Output, and Fertility of Mature Dairy Bulls Ejaculated Daily or Weekly for Thirty-Two Weeks

Summary Ten aged dairy bulls were used to measure the effects of prolonged daily ejaculation on libido, sperm output, sperm characteristics, and fertility. The ten bulls were ejaculated once a week for a 4-wk. preliminary period after which five were chosen at random to be ejaculated once a day and five once a week for a 32-wk. experimental period. The bulls ejaculated once a week required an average of 9.2min. of active sexual stimulation and 2.9 false mounts before each ejaculation, as compared to an average of 16.0min. and 3.7 false mounts for the bulls ejaculated once a day. The weekly bulls yielded an average of 9.5ml. of semen per ejaculate, 63% motile sperm, 1.89 billion sperm per milliliter of semen, 4.8 billion total sperm per ejaculate (per week), and 11.1 billion motile sperm per ejaculate (per week). The bulls ejaculated once daily yielded an average of 6.2ml. of semen per ejaculate, 69% motile sperm, 0.81 billion sperm per milliliter of semen, 4.8 billion total sperm per ejaculate, 3.4 billion motile sperm per ejaculate, 33.8 billion total sperm per week, and 23.6 billion motile sperm per week. All of the differences between the two frequencies of ejaculation, with respect to the sperm output criteria, were statistically signicant (P Determinations of the per cent vitality stained sperm and the per cent of sperm with morphological abnormalities and estimation of the per cent of motile sperm in extended semen after three intervals of storage at −79. 5, and 15–25° C. revealed no significant differences between the two frequencies of ejaculation. Measured by the per cent of cows not returning to service within 60 to 90 days after first insemination, the average fertility of 70% for 42,136 inseminations with sperm from the bulls ejaculated once a week was not significantly different from the average of 73% for 7,108 inseminations with sperm from the bulls ejaculated once a day. The results of this experiment indicate that daily ejaculation of aged bulls for as long as 8 mo. is not harmful, either to the bulls themselves or to the quality of the sperm they produce. Ejaculating bulls two or three times on each of two or three days a week and storing the sperm in an improved extender, such as CUE, makes it possible for an artificial breeding organization to provide unfrozen semen with satisfactory fertility at all times from most stud bulls.

Semen Production, Fructose Content of Semen and Fertility of Dairy Bulls as Related to Sexual Excitement

Summary Three levels of sexual excitement, namely unrestraint, one false mount and two false mounts prior to the first ejaculate, were related to semen production, semen characteristics, fructose concentration and fertility of the semen of mature dairy bulls in two 18-wk. experiments. It was found that all of these criteria of responses except fertility can be influenced markedly by controlled sexual excitement. There appears to be an inverse relationship between fructose concentration and spermatozoan density of semen. The results indicate that one false mount can be recommended for routine practice by bull studs.