Endocrine and thermal responses to GnRH treatment and prediction of sperm output and viability in Holstein-Friesian Breeding Bulls

• Published in: Theriogenology Vol. 50; no. 2; pp. 177 - 183
• Main Authors: Gábor, G, Sasser, R.G, Kastelic, J.P, Coulter, G.H, Everson, D.O, Falkay, G, Mézes, M, Bozó, S, Cook, R.B, Csik, J.V.ölgyi, Bárány, I, Szász, F
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.07.1998
• Subjects: Animals; BLOOD SERUM; BODY MEASUREMENTS; BODY TEMPERATURE; BOVIN LAITIER; BULLS; Cattle - physiology; DAIRY CATTLE; ECHOGRAPHIE; ECHOGRAPHY; echotexture; ECOGRAFIA; ESCROTO; ESPERMATOZOO; GANADO DE LECHE; GONADOLIBERINE; GONADOTROPIN RELEASING HORMONE; Gonadotropin-Releasing Hormone - administration & dosage; Gonadotropin-Releasing Hormone - pharmacology; HORMONA LIBERADORA DE GONADOTROPINA; Injections, Intramuscular; Luteinizing Hormone - blood; Male; MEDICION DEL CUERPO; MENSURATION CORPORELLE; SCROTUM; SEMEN; SEMEN CHARACTERS; SERUM SANGUIN; SPERMATOZOA; Spermatozoa - drug effects; SPERMATOZOIDE; SPERME; SUERO SANGUINEO; Surface Properties; TAUREAU; TEMPERATURA DEL CUERPO; TEMPERATURE CORPORELLE; TESTES; TESTICULE; TESTICULOS; TESTOSTERONAS; TESTOSTERONE; Testosterone - blood; thermography; TORO; ULTRASON; ULTRASONICS; ULTRASONIDO; ULTRASONOGRAPHY; VIABILIDAD; VIABILITE; VIABILITY; semen; echotexture; bulls; thermography; testes
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/S0093-691X(98)00124-1

A study was conducted to determine changes in serum LH and testosterone concentrations and in scrotal surface temperature (SST; measured with infrared thermography) following GnRH treatment and to predict the number of spermatozoa collected and the proportion that were viable. Holstein-Friesian breeding bulls (n=22, average age, 24.3 mo; range, 15 to 41 mo) were examined twice 30 d apart. Concurrently, semen was collected twice weekly with an artificial vagina. Treatment with GnRH (100 μg, im) increased (P<0.0001) serum LH and testosterone concentrations and increased (P<0.0001) SST (range 0.6 to 1.1°C; P<0.05) at the top and bottom of the scrotum. In regression models to predict the total number of spermatozoa, significant independent variables included ultrasonic echotexture of the testes (negative slope), scrotal width (positive slope) and SST at the bottom of the scrotum 45 min after GnRH treatment (positive slope). In regression models to predict the percentage of live spermatozoa, ultrasonic echotexture was a significant independent variable (negative slope). Measurement of testicular ultrasonic echotexture and SST after GnRH treatment augmented measurement of testicular size for predicting the number and percentage of live spermatozoa.