Efficacy of caudal epidural injection of lidocaine, xylazine and xylazine plus hyaluronidase in reducing discomfort produced by electroejaculation in bulls.

To test the hypothesis that epidural administration of lidocaine, xylazine or xylazine plus hyaluronidase provides reduced pain and stress during electroejaculation in bulls, eight 30-month-old Nellore bulls received saline solution (control), 2% lidocaine, 2% xylazine or 2% xylazine plus hyaluronidase injected into the first intercoccygeal (Co1-Co2) epidural space in randomized order. Heart rate, respiratory rate, mean arterial pressure, analgesia, animal behavior and motor blockade were evaluated before treatment and at predetermined intervals during and after treatment. Pain and stress were scored subjectively, and semen quality was evaluated. The onset of anesthetic action was significantly faster with lidocaine (3.0 ± 1.2 min) than with xylazine or xylazine plus hyaluronidase (8.9 ± 1.5 and 5.5 ± 2.6 min, P=0.021 and P=0.012, respectively), and the onset of anesthesia with xylazine plus hyaluronidase was significantly faster than that with xylazine alone (P=0.032). Treatment with xylazine or xylazine plus hyaluronidase resulted in less discomfort than treatment with lidocaine, as indicated by animal behavior. Changes in heart rate, respiratory rate and arterial pressure were within acceptable limits. Penile protrusion and semen emission occurred in all animals during all four treatments. Our results suggest that xylazine plus hyaluronidase reduced discomfort during electroejaculation more effectively than xylazine or lidocaine alone. Further experiments are necessary to determine whether electroejaculation with xylazine plus hyaluronidase is feasible for obtaining semen from Nellore bulls unaccustomed to being handled or restrained.

Testis morphometry and kinetics of spermatogenesis in the feral pig (Sus scrofa).

The feral pig (Sus scrofa sp) also known as Monteiro pig, originated from a domestic pig breed that was introduced into Pantanal region in Brazil in the eighteenth century. Although the feral pig has commercial potential, there are few reports in the literature concerning the reproductive biology of this species. Therefore, the aim of this study was to further describe the feral pig testis parenchyma as well as characterize the stages of the seminiferous epithelium cycle by tubular morphology method, and to evaluate the number of differentiated spermatogonia generations in this species. Eight sexually mature feral pigs were analyzed. Fragments of testes were embedded in plastic resin and used to prepare slides for morphometrical studies. It was concluded that the feral pig has six generations of differentiated spermatogonials (A1, A2, A3, A4, In, B) and that the cellular composition in the eight stages of the seminiferous epithelium cycle of these animals were very similar to those reported in species of suidae and tayssuidae already studied.

Proliferation of seminiferous epithelium cells during the postnatal development in goats.

The objective of this research study was to evaluate the proliferation of somatic and germ cells in the seminiferous epithelium of Alpine goats. A total of 47 goats reared in semi-intensive conditions were used, divided into age groups from birth up to 12 months of age. Following castration, testis fragments were included in plastic resin and were mounted in Entellan(®) for histometric evaluations. In general, the total number of germ cells per seminiferous cord transverse section was low until 4 months of age. An increase was observed between 4 and 5 months, lasting until 9 months of age. From that age on, this number tended to stabilize, until 12 months. The population of support cells (undifferentiated support cells and Sertoli cells) remained constant from birth to the first month, when it peaked. This was followed by a reduction until the fifth month of age. From that age on, there was differentiation in mature Sertoli cells, and its population remained constant until 12 months of age. It can be concluded that Alpine goats were in the impuberal phase from birth to 3 months of age, prepuberal phase during the fourth month, reached puberty at 5 months of age, postpuberal phase from 6 to 8 months, and reached sexual maturity at 9 months of age. Overall yield of spermatogenesis and Sertoli cell index increased from puberty up to the 12th month of age.

Characterization and activity of angiotensin-converting enzyme in Holstein semen.

The study was designed to perform immunodetection in spermatozoa and seminal plasma, immunolocalization in spermatozoa, and evaluation of the enzymatic activity of angiotensin-converting enzyme (ACE) in the semen of Holstein bulls. We used ejaculates from five bulls as part of a regular collection of semen. The monoclonal anti-ACE antibody recognized a single protein band with 100 kDa in detergent extract prepared from sperm and in seminal plasma. ACE enzymatic activity in sperm was 43.7, 21.3, 45.6, 60.0, and 57.7 mU/mL in bulls 1, 2, 3, 4, and 5, respectively, and 0.3, 2.3, 3.0, 2.3, and 2.6 mU/mL in seminal plasma of the same bulls, respectively. The average percentages of sperm with acrosome reactions after treatment with heparin were 28.3%, 28.6%, 35.2%, 25.0%, and 32.3%, respectively. These values were higher than the percentages of acrosome reactions in controls and the captopril group (P<0.05), although no difference was seen between the captopril and control groups (P>0.05). After 4h of incubation, motility in the control group (32.9%) was significantly higher than that in the heparin (15.7%) and captopril (12.1%) groups. No difference was found in motility after the capacitation assay in the heparin and captopril groups (P>0.05). In conclusion, ACE was immunologically localized in the acrosome of the spermatozoa of Holstein bull, the specific enzymatic activity of ACE in detergent-extracted spermatozoa and seminal plasma was inhibited by captopril, and this ACE inhibitor reduced the percentage of sperm with progressive motility and acrosome reactions after capacitation in vitro.

Pregnancy rate of Nelore females inseminated with male-sexed semen.

Pregnancy rates of Nelore females inseminated with male-sexed semen and conventional semen from the same bulls were evaluated. The females included 433 heifers (2 years old) and 230 non-suckling cows, totaling 663 animals. Average body condition score was 3.5 (1-5 scale). Estrus was induced with prostaglandin F2α. The total pregnancy rate of females inseminated with male-sexed semen of bulls A, B and C was 38.8% (131/338) less (P<0.0001) than the total pregnancy rate observed for females inseminated with conventional semen from the same bulls (57.9% [188/325]). Pregnancy rates of non-suckling cows inseminated with male-sexed semen was 43.3% (49/113), which was similar (P≥0.05) to the values found for heifers inseminated with male-sexed semen from the same bulls (36.4% [82/225]). The pregnancy rate of females inseminated with male-sexed semen was less compared with females inseminated with conventional semen. In addition, there was no significant difference in the pregnancy rate of heifers versus non-suckling cows.

Intrinsic rate of spermatogenesis in free-ranging feral pigs (Sus scrofa sp).

The aim of this research was to evaluate the intrinsic rate of spermatogenesis in adult free-ranging feral pigs. Twelve adult male free-ranging feral pigs were captured, sedated, and orchidectomized, and then were released and observed to complete recovery and return to their natural environment. Fragments of the testes were embedded in plastic resin and used to prepare slides for histometric analysis. Characteristics investigated included cell populations in the seminiferous epithelium in stage 1 of the cycle of the seminiferous epithelium, intrinsic rate of spermatogenesis and Sertoli cell index. The efficiency coefficient of spermatogonial mitosis was 7.59, the meiotic index was 3.03, the overall yield of spermatogenesis was 23.97 and the cell loss ratio during the meiotic prophase was 1.04. Each Sertoli cell supported an average of 0.92 type A spermatogonia, 7.01 primary spermatocytes in preleptotene/leptotene, 7.30 primary spermatocytes in pachytene and 22.16 round spermatids. In conclusion, the results of the present study indicate that the supporting capacity of Sertoli cells in free-ranging feral pigs is among the greatest values reported for most domestic animals, and the overall yield of spermatogenesis is comparable to that reported in wild boars.

Kinetics of spermatogenesis in the white-lipped peccary (Tayassu pecari).

This study aimed to characterize the stages of the seminiferous epithelium cycle by the tubular morphology method, and to determine the number of differentiated spermatogonia generations in the adult white-lipped peccary. Twenty adult white-lipped peccaries, obtained from commercial slaughterhouse, were used. Fragments of the testicular parenchyma were fixed in 3% glutaraldehyde and embedded into a methacrylate resin. The number of germ and Sertoli cells was estimated by the analysis of cell populations in 50 transversal sections of seminiferous tubules in different stages of the cycle. The tubular morphology method allowed the identification of cellular associations characteristic of the eight stages of the seminiferous epithelium cycle in white-lipped peccaries. The results showed the presence of six generations of differentiated spermatogonia in white-lipped peccaries, and that the cell composition of the eight stages of the seminiferous epithelium cycle in this species is very similar to that described for collared peccaries.

Somatic and germ cell proliferation during post-natal development of the testis in the wild boar (Sus scrofa scrofa).

This study aimed to investigate the proliferation of cells in the seminiferous epithelium, the intrinsic rate of spermatogenesis and Sertoli cell index in wild boars, during the period from birth to 12 months of age. A total of 52 animals raised in captivity were assigned to 13 experimental groups. After unilateral orchidectomy, fragments of the testes were embedded in plastic resin and used to prepare slides for histometric analysis. Variables assessed in each age group included the characterization of cell populations in the seminiferous epithelium, the intrinsic rate of spermatogenesis, Sertoli cell index and the stages of testicular development in each animal. Gonocytes were in greater numbers in newborn animals, and by the fourth month were no longer identified. The population of spermatogonias increased from 3 to 9 months, after that showed a tendency to stabilization. Primary spermatocytes in pre-leptotene/leptotene were first seen in 8-month-old animals. Primary spermatocytes in pachytene, and round spermatids increase gradually in frequency in animals from 9 to 12 months of age. Undifferentiated support cells were very frequent at birth to 7 months and increased between 7 and 8 months, after that there was a tendency for no further increase in this cell type. We conclude that the Sertoli cell population stabilized in the pre-pubertal phase and germ cell population increased after puberty. The overall yield of spermatogenesis and Sertoli cell index were greater in animals around 12 months of age.

Spermatogenesis in white-lipped peccaries (Tayassu pecari).

We describe here morphological and functional analyses of the spermatogenic process in sexually mature white-lipped peccaries. Ten sexually mature male animals, weighing approximately 39 kg were studied. Characteristics investigated included the gonadosomatic index (GSI), relative frequency of stages of the cycle of seminiferous epithelium (CSE), cell populations present in the seminiferous epithelium in stage 1 of CSE, intrinsic rate of spermatogenesis, Sertoli cell index, height of seminiferous epithelium and diameter of seminiferous tubules, volumetric proportion of components of the testicular parenchyma and length of seminiferous tubules per testis and per gram of testis. The GSI was 0.19%, relative frequencies of pre-meiotic, meiotic and post-meiotic phases were, respectively 43.6%, 13.8% and 42.6%, general rate of spermatogenesis was 25.8, each Sertoli cell supported an average 18.4 germinative cells, height of seminiferous epithelium and diameter of seminiferous tubules were, respectively, 78.4 microm and 225.6 microm, testicular parenchyma was composed by 75.8% seminiferous tubules and 24.2% intertubular tissue, and length of seminiferous tubules per gram of testis was 15.8m. These results show that, except for overall rate of spermatogenesis, the spermatogenic process in white-lipped peccaries is very similar to that of collared peccaries, and that Sertoli cells have a greater capacity to support germinative cells than most domestic mammals.