Reproductive Physiology of the Stallion. II. Daily Production and Output of Sperm2

Gebauer, Matthias; Pickett, B.W.; Swierstra, E. E.

doi:10.2527/jas1974.394732x

Cited by 64 publications

(46 citation statements)

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“…Ao longo do período experimental, cada reprodutor foi submetido a três ou quatro mensurações, em que cada órgão foi mensurado individualmente, utilizando-se um paquímetro, conforme descrito por GEBAUER et al (1974) e adaptado por GEBER (1995) para asininos, após a coleta de sêmen. Foram mensurados o comprimento testicular (CT -crânio caudal), a altura testicular (AT -dorso ventral) e a largura testicular (LT -médio lateral) em ambos os testículos.…”

Section: Methodsunclassified

Alguns aspectos biométricos do aparelho genital externo de jumentos doadores de sêmen da raça Pêga

et al. 2009

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Alguns aspectos biométricos do aparelho genital externo de jumentos doadores de sêmen da raça PêgaSome biometric aspects of the external genital tract from donkey Pêga breed semen donors RESUMO Pêga, com peso médio de 272±34, de 7,4 (5,9 a 9,6), e o VT esquerdo foi de 155,5±14,4mL, enquanto o direito foi de 149,3±14,9. A medida de FUND foi de 25,3±3,3mm (20,3a 30,8mm) (TH -dorso ventral) and thickness of spermatic funiculum (FUN -third part). The biometric data from biometric testis were used to calculate the testis indices (TI) and testis volume (TV). The TI observed was 7.4 (5.9 a 9.6) and TV was 155.5±14.4, 149.3±14.9 respectively left and right. The average FUN was 25.3±3.3mm (20.3 a 30.8mm) O presente estudo foi conduzido com seis jumentos reprodutores da raça altura testicular (AT -dorso ventral), largura testicular (LT -médio lateral) e espessura do funículo (FUNterço médio). Os dados de biometria testicular foram utilizados para o cálculo do índice testicular (IT) e volume testicular (VT). O IT médio observado foi Palavras-chave: biometria, volume, índice testicular. ABSTRACT The present study was performed with six Pêga breed donkeys, weight from 231 to 326kg (272±34.9). The breeders were divided into the adult group (J1, J2 e J3, 15 years old average) and the young group (J4, J5 e J6, 3.5 years old average). . The donkeys presented normal rates of fertility

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Section: Methodsunclassified

Alguns aspectos biométricos do aparelho genital externo de jumentos doadores de sêmen da raça Pêga

et al. 2009

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“…Five pieces of testis obtained from the locally-fixed, equatorial region were placed in the same fixative and stored at 5°C until being placed in 1% Os04 in the same buffer for 1 h. This sampling method is appropriate as uniformity among different regions ofthe horse testis has been described (Gebauer et al, 1974;Johnson et al, 1978). Tissues were dehydrated in ethanol and embedded in Epon 812.…”

Section: Introductionmentioning

confidence: 99%

Effect of seasonal changes in Leydig cell number on the volume of smooth endoplasmic reticulum in Leydig cells and intratesticular testosterone content in stallions

Johnson¹,

Thompson²

1987

Reproduction

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“…The efficiency of spermatogenesis can be estimated by the number of spermatozoa produced per day per gram of testicular parenchyma (DSP/g; Amann, 1970b;Johnson, 198613;Swierstra et al, 1974). This parameter allows comparison among species as it is not influenced by species differences in the size of the testis.…”

Section: Definition Of Spermatogenesis and Its Efficiencymentioning

confidence: 99%

Efficiency of spermatogenesis

Johnson

1995

Microscopy Res & Technique

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Spermatogenesis is a process of division and differentiation by which spermatozoa are produced in seminiferous tubules. A measure of efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma. This measure is not influenced by species differences in testicular size; however, it is influenced by species differences in the numerical density of germ cells and in the life spans of these cells. Seminiferous tubules are composed of somatic cells (myoid cells and Sertoli cells), and germ cells (spermatogonia, spermatocytes, and spermatids). Activity of these three germ cells divide spermatogenesis into spermatocytogenesis, meiosis, and spermiogenesis, respectively. Spermatocytegenesis involves mitotic cell division to increase the yield of spermatogenesis and to produce stem cells and primary spermatocytes. Meiosis involves duplication and exchange of genetic material and two cell divisions that reduce the chromosome number and yield four spermatids. Spermiogenesis is the differentiation of spherical spermatids into mature spermatids which are released at the luminal free surface as spermatozoa. The spermatogenic cycle is superimposed on the three major divisions of spermatogenesis. Spermatogenesis and germ cell degeneration can be quantified from numbers of germ cells in various steps of development throughout spermatogenesis, and quantitative measures are related to number of spermatozoa in the ejaculate. Germ cell degeneration occurs throughout spermatogenesis; however, the greatest impact occurs during spermatocytogenesis and meiosis. Efficiency of spermatogenesis is related to the amount of germ cell degeneration, pubertal development, season of the year, and aging of humans and animals. Number of Sertoli cells and amount of smooth endoplasmic reticulum of Leydig cells (but not Leydig cell number) are related to efficiency of spermatogenesis. In humans, efficiency of spermatogenesis is reflected in number of spermatogenic stages per cross-section and number of missing generations within each stage; however, the arrangement of stages along the tubular length does not reflect differences in the efficiency of spermatogenesis. In short, spermatogenesis involves both mitotic and meiotic cell divisions and an unsurpassed example of cell differentiation in the production of the spermatozoon, and daily sperm production per g parenchyma is a measure of its efficiency.

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Reproductive Physiology of the Stallion. II. Daily Production and Output of Sperm2

Cited by 64 publications

References 0 publications

Alguns aspectos biométricos do aparelho genital externo de jumentos doadores de sêmen da raça Pêga

Alguns aspectos biométricos do aparelho genital externo de jumentos doadores de sêmen da raça Pêga

Effect of seasonal changes in Leydig cell number on the volume of smooth endoplasmic reticulum in Leydig cells and intratesticular testosterone content in stallions

Efficiency of spermatogenesis

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