Kallikrein proteoforms and reproductive parameters in stallion are conditioned by climate.

Horses are seasonal polyoestrous animals, and the photoperiod is the main factor modulating their reproductive activity. There is no consensus on the andrological and biochemical factors that influence breeding seasonality. To assess the involvement of climate in reproduction, Mangalarga Marchador stallions were monitored over 1 year regarding semen quality and seminal plasma proteome.

Could metal exposure affect sperm parameters of domestic ruminants? A meta-analysis.

During the last decade, environmental toxicants have been considered a potential cause for declining sperm quality. Toxic metals are not easily degraded and may accumulate along the food chain, which may negatively impact the semen quality of animals. In this framework, we conducted a meta-analysis to determine whether exposure to Al, As, Cd, Cr, Co, Cu, Fe, Mg, Mn, Hg, Ni, and Pb affects sperm and andrological parameters of domestic ruminants.

Nonlinear Models to Describe the Testicular Size Growth Curve of Mangalarga Marchador Stallions.

This study aimed to describe the testicular growth curve in Mangalarga Marchador stallions fitting nonlinear models to data of total scrotal width (TSW) and testicular volume (TV). A cross-sectional study was conducted with 120 stallions, aging from 1.75 to 21.

Use of nonlinear mixed models for describing testicular volume growth curve in Nellore bulls.

This study aimed to describe longitudinal testicular volume (TV) data of Nellore bulls by using nonlinear mixed models. Dataset consisted of 2,294 TV measurements from 505 bulls with ages ranging from 563 to 4,307 days. Nine nonlinear models were evaluated: Brody, Gompertz, Hill, Logistic I and II, Meloun, Michaelis-Menten, Mitscherlich and von Bertalanffy.

In vitro evaluation of cryopreserved bovine sperm and its relation to field fertility in fixed-time artificial insemination.

This study aimed to assess characteristics of bovine cryopreserved sperm and evaluate its relation to field fertility in fixed-time artificial insemination (FTAI). Semen samples of 16 bulls were used to inseminate 811 Nellore cows, and four of these bulls were also used to inseminate 101 Nellore heifers. Samples of the same ejaculate used for FTAI from each bull were analysed in the laboratory after thawing.

Relationship of testicular biometry with semen variables in breeding soundness evaluation of Nellore bulls.

This study aimed to evaluate the correlation between testicular biometry and semen variables, as well as, to relate testicular variables to the probability of selecting Nellore bulls with desirable sperm morphology when conducting breeding soundness evaluations (BSE). A total of 2055 BSEs from 506 bulls comprised the dataset. Biometric variables evaluated were: scrotal circumference, testicular volume, width, length, ratio and eccentricity; and semen variables were sperm motility, major sperm defects, minor sperm defects and normal sperm.