Gram Of Testis Research Articles

Observations on the reproductive physiological status of mature herd bulls, bachelor bulls, and young bulls in the hippopotamus Hippopotamus amphibius amphibius linnaeus

Average age of herd bulls was 33 yr and their heart girth averaged 2.91 m, cf. 24 yr and 2.73 m for bachelor bulls. The weight of the testes in herd bulls was 571 g and they contained 97.0 ng/g testosterone for a total of 51.2 μg, cf. 523.4 g, 188.8 ng/g, and 97.6 μg, respectively, for bachelor bulls. Seminiferous tubule diameter in herd bulls was 147.6 μm, cf. 146.5 μm. The epididymes in herd bulls weighed 209.6 g and contained 46,148 × 10 6 spermatozoa, cf. 206.4 g and 39,999 × 10 6 for bachelor bulls. Young bulls appear to be tolerated in the herd until 7–8 yr of age. At this time heart girth was 2.52 m and the testes weighed 366.5 g and contained 74.4 ng testosterone per gram of testis for a total of 28.2 μg testosterone. Tubule diameter was 131.0 μm. The epididymes weighed 127 g and contained 12,545 × 10 6 spermatozoa.

Semen and Testis Characteristics in Young Yorkshire and Lacombe Boars

Twenty-two Yorkshire boars (average age 9.2 months) and 22 Lacombe boars (average age 9.2 months) were ejaculated at 48-hr, intervals for an 8-week period. For the York-shire boars the average values for the different semen components were: semen volume, 225 ml.; strained volume,178 ml.; gel volume, 47 ml.; sperm concentration, 143×106 per ml.; total sperm per ejaculate, 23.1 ×lO9; and motile sperm per ejaculate, 17.3×109. Corresponding values for the Lacombe boars were 228, 176, 52, 138×106, 21.7×109 and 15.0×lO9. No significant differences were observed between the two breeds in regard to the previously listed semen components, but significant differences were found among boars within a breed with respect to these components. Also, there was considerable variation among ejaculates in the same boar. Initial ejaculates were of poorer quality than ejaculates obtained during final weeks of the semen collection period. Generally, there was a high positive correlation between total volume and gel volume, and between sperm concentration and total sperm per ejaculate. There appeared to be no direct relationship between total volume and total sperm per ejaculate, or between strained volume and total sperm per ejaculate. In most boars sperm concentration decreased when total volume of the ejaculate increased. The two breeds differed significantly (P<,.01) with respect to duration of ejaculation. The average ejaculation time of the Yorkshire boars was 5.7 min. and of the Lacombe boars, 7.2 min. The collection equipment, cheesecloth (used for removing the gel fraction) and gel retained 1.49, 1.44 and 0.35%, respectively, of the total sperm counted in the collection bottle. In both breeds the combined testis weight comprised 0.46% of total body weight. The sperm output per gram of testis per 48-hr. was on the average 44.4×lO6 sperm for the Yorkshire boars and 40.4×106 sperm for the Lacombe boars. The two breeds did not differ significantly in sperm output per gram of testis. Sperm output was correlated (0.51, P<.01) with combined testis weight.

STRUCTURAL COMPOSITION OF SHORTHORN BULL TESTES AND DAILY SPERMATOZOA PRODUCTION AS DETERMINED BY QUANTITATIVE TESTICULAR HISTOLOGY

The structural composition of the testes, the sperm output, and the daily sperm production were determined in seven 18-month-old Shorthorn bulls. The testicular components classified composed the following percentages of the total testis volume: spermatogonium nuclei,.62%; primary spermatocyte nuclei, 4.57%; secondary spermatocyte nuclei,.16%; spermatid nuclei, 3.52%; spermatozoa,.34%; tubular cytoplasm, 57.79%; lumen, 4.67%; basement membrane, 2.60%; intertubular space, 23.63%; and Sertoli cells, 2.04%. The seminiferous tubules made up 76.4% of the testis volume. It was estimated that the testes contained on the average 1630 m (range 960–2240 m) of seminiferous tubules. The tunica albuginea comprised 12.8% of the testis weight.Three procedures are described for measuring daily sperm production from quantitative testicular histology, and the results obtained with Shorthorn bull testes are presented. The limitations of the three procedures are discussed. It was estimated that 18-month-old Shorthorn bulls produced 5.3 × 109 sperm per day. This represented a production of 16.9 million sperm per gram of testis per day. Within a given species sperm production appears to be primarily a function of testis size. The seven bulls averaged 2.7 × 109 sperm per ejaculate when semen samples were collected every other day with an electroejaculator. This represented about 25% of the sperm production by the testes.

Reproductive Capacity of Dairy Bulls. VIII. Direct and Indirect Measurement of Testicular Sperm Production1,2,3

Summary It was desired to determine testicular daily sperm production (DSP) and compare it with daily sperm output (DSO). Two independent calculations of DSP for each testis from eight 2-yr-old and four mature Holstein bulls were based on counts of gonadal sperm reserves and on quantitative testicular histology. Limitations of the proposed methods and formulas were discussed. The duration of spermatogenesis in bulls was calculated to be 60 days. The average DSP values calculated from gonadal sperm reserves and histological data were 9.98 and 12.76 billion per bull. The differences between DSP values for the 24 testes by the two methods of calculation were highly significant, but the two values were correlated (+0.81). However, testis weight accounted for most of the relationship, since the correlation was not significant when calculated on the basis of DSP per gram of testis (+0.28). Since the validity and repeatability of these methods has not been established, the two DSP values were averaged and ranged from 7.7 to 13.2 billion for eight bulls of similar age and body weight. The DSO during collection of six ejaculates weekly with intensive sexual preparation (6×) also was obtained for the 12 bulls. About five months elapsed between collection of DSO data and postslaughter determination of DSP. The DSO on 6× averaged 4.81 ± 0.35 billion, or only 42% of the mean DSP of 11.49 ± 0.64 billion. However, the highly significant correlation between DSP and DSO on 6× (+0.87) suggests that DSP can be estimated in individual living bulls by collecting semen at a suitable high ejaculation frequency.