Effects of environmental factors, age and genotype on sperm production and semen quality in Bos indicus and Bos taurus AI bulls in Brazil

The effects of ambient temperature and humidity, month, age and genotype on sperm production and semen quality in AI bulls in Brazil were evaluated. Data from two consecutive years were analyzed separately. Seven Bos indicus and 11 Bos taurus bulls from one artificial insemination (AI) center were evaluated in Year 1 and 24 B. indicus and 16 B. taurus bulls from three AI centers were evaluated in Year 2. Ambient temperature and humidity did not significantly affect sperm production and semen quality, probably because there was little variation in these variables. Month accounted for less than 2% of the variation in sperm production and semen quality. Increased bull age was associated with decreased sperm motility (P < 0.10) and increased minor sperm defects (P < 0.001) in Year 1. B. indicus bulls had greater (P < 0.005) sperm concentration than B. taurus bulls in both years (1.7 x 10(9)/ml versus 1.2 x 10(9)/ml in Year 1 and 1.6 x 10(9)/ml versus 1.2 x 10(9)/ml in Year 2, respectively). Ejaculate volume was not significantly affected by genotype in Year 1 (6.6 ml versus 6.9 ml in B. indicus and B. taurus bulls, respectively), but B. indicus bulls had greater (P < 0.05) total (11.4 x 10(9) versus 8.2 x 10(9)) and viable (6.7 x 10(9) versus 4.9 x 10(9)) numbers of spermatozoa in the ejaculate than B. taurus bulls. In Year 2, B. taurus bulls had greater (P < 0.05) ejaculate volume than B. indicus bulls (8.2 ml versus 6.7 ml, respectively) and total and viable number of spermatozoa in the ejaculate were not significantly different between genotypes (10.3 x 10(9) versus 9.1 x 10(9) and 6.1 x 10(9) versus 5.4 x 10(9) in B. indicus and B. taurus bulls, respectively). Sperm motility was not significantly affected by genotype (mean, 59%). In Year 1, B. indicus bulls tended (P < 0.10) to have more major sperm defects and had more (P < 0.05) total sperm defects than B. taurus bulls (11.8% versus 8.7% and 13.6% versus 10.0%, respectively). In Year 2, B. indicus bulls tended (P < 0.10) to have more total sperm defects than B. taurus bulls (16.2% versus 13.3%, respectively). In conclusion, neither ambient temperature and humidity nor month (season) significantly affected sperm production and semen quality. B. indicus bulls had significantly greater sperm concentration and B. taurus bulls had significantly fewer morphologically defective spermatozoa. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Gonadic Sperm Reserve in Buffaloes Created under Tropical Conditions

The objective of the present study was quantifying the spermatic production per gram and daily rate of the testicular parenchyma. Testis of 12 crossbred Murrah buffaloes aged 24 to 48 months created under extensive conditions in the State of São Paulo/Brazil were analyzed. Animals were divided into groups based on the testicular shape (long and long-moderate) and testicular sides (right and left) and the studied parameters were: length and testicular width, weight and volume of the albuginea and mediastinum and net weight of the testicular parenchyma, gonadic sperm reserves, spermatic production/g of testicular parenchyma, daily spermatic production/g, total daily spermatic production, resulting into the values: 8.16 +/- 0.87 and 4.29 +/- 0.50 cm; 9.09 +/- 1.91 g and 8.77 +/- 1.88 mL; 0.97 +/- 0.39 g and 0.90 +/- 0.38 mL; 112.91 +/- 18.85 g; 14.32 x 10(9) +/- 0.15; 13.42 x 10(6) +/- 0.17; 27.40 x 10(6) +/- 0.35 and 2.92 x 10(9) +/- 0.30, registering no difference between right and left testis in relation to the parameters (P>0.05). There was no relation between testicular biometry and spermatic production (P>0.05). According to the obtained values, all animals were considered sexually mature and presented an efficient spermatic production per gram of testicular parenchyma and total daily production.

Tritrichomonas fetus extracellular products decrease progressive motility of bull sperm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Impact of 24-h Cooling Prior to Freezing on the Survival of Domestic Cat (Felis catus) Epididymal Sperm

The aim of this study was to investigate the impact of a 24-h cooling period prior to freezing on domestic cat epididymal sperm viability. Fifteen tomcats were submitted to routine orchiectomy and sperm samples were retrieved from both epididymides in a Tris-glucose-20% egg yolk extender. For each tomcat, the diluted sperm was split into two equal volumes and cooled to 5 degrees C at a rate of 0.5 degrees C/min; one sample for 60 min (control) and the other for 24 h (cooled). After the cooling period, samples from both groups were frozen using an identical freezing protocol. Sperm samples were evaluated in three different periods: immediately after harvesting, after cooling at 5 degrees C for 24 h (cooled group) and after freezing thawing of control and cooled groups. Evaluations consisted of sperm motility and progressive status, sperm morphology and plasma membrane integrity (PMI) using two fluorescent probes. After cooling for 24 h, a decrease (p < 0.05) in sperm motility, progressive status and PMI was observed when compared to sperm samples immediately after collection. Comparing the results obtained after thawing, no difference (p < 0.05) was found regarding sperm motility, progressive status, PMI and sperm morphology between control and cooled groups. The results from the present study show that cooling cat epididymal spermatozoa at 5 degrees C for 24 h prior to freezing does not lead to major damage of spermatozoa impairing the freeze-thaw process.

Osteopontin in Seminal Plasma and Sperm Membrane of Dogs

The objective of this work was to describe the presence of osteopontin (OPN) in canine seminal plasma and sperm membranes. A pool of seminal plasma and sperm membrane extract from 30 dogs was used. Polyacrylamide electrophoresis gels were performed and the bands were transferred to nitrocellulose paper and Western blot was undertaken using an antibody anti-OPN. Two and 12 bands were marked in the seminal plasma (77.2 and 15.6 kDa) and sperm membrane extracts (70.6-26.6 kDa), respectively. However, from 12 marked bands in the sperm membrane extract, only three (46.4, 37.7 and 36.5 kDa) were strongly marked. We conclude that, seminal plasma and sperm membranes from dogs contain different isoforms of OPN; yet, further studies will be necessary to determine their function in this species.

Fertilizing Capacity of Frozen Epididymal Sperm Collected from Dogs

The collection of epididymal sperm may be a valuable tool for canine reproduction especially since it can enable collection of cells after death of a valuable dog. The aim of the present study was to evaluate the viability of epididymal sperm after freeze-thawing. Epididymides were obtained from four adult dogs by elective orchiectomy. The caudal portion of the epididymides and part of the deferential ducts were squeezed by means of an anatomic clamp into a Petri dish containing either 0.9% saline solution (Group 1) or Ringer solution without lactate (Group 2). Samples were centrifuged at 800 x g for 10 min, the supernatant was removed and the pellet was diluted in one step with a Tris/citric acid/OEP (Orvus Es Paste) extender containing 7% glycerol and subjected to semen freezing. Oocytes were obtained from canine ovaries, after ovariohysterectomy. Only oocytes that were approximately 100 mu m in diameter, with a dark ooplasm surrounded by three-or four-well formed cumulus cell layers were used for sperm testing. Frozen semen samples were thawed in a water bath at 70 degrees C for 8 s and analysed at room temperature for sperm motility and velocity. Oocytes were incubated with spermatozoa in humidified atmosphere containing 5% CO(2) at 38 degrees C for 18 h. Morphological and functional characteristics of spermatozoa were similar in both groups. However, the percentage of sperm cells bound to oocytes was significantly higher in Group 2 than in Group 1. This result suggests that the Ringer solution without lactate was a more suitable medium for collecting epididymal canine sperm than 0.9% saline.