The relationship between sperm quality in cool-shipped semen and embryo recovery rate in horses.

The relationship between the quality of cool-shipped stallion semen and fertility has not been adequately described. This study evaluated sperm quality of cool-shipped semen from 459 ejaculates (N = 130 stallions) that were used for insemination of 196 embryo donor mares (n = 496 estrous cycles). Embryo recovery rate (ERR; %) increased, as all sperm measures (e.g., motility, viability, DNA quality, morphology, concentration, and total number) increased. Threshold values are reported for each sperm quality measure (e.g., total sperm motility ≥ 65%) that separate two ERR groups (e.g., average: ∼50% ERR; high: ∼65% ERR).

Plasma endotoxin concentrations in experimental and clinical equine subjects.

Endotoxin (LPS) was quantitated in experimental subjects and in horses with naturally occurring gastrointestinal strangulation obstruction and/or septicaemic diseases to establish the fate of LPS and the clinical usefulness of the Limulus amoebocyte lysate (LAL) assay. The assay was validated for sensitivity (10 pg/ml), recovery (90 to 106 per cent), intra-assay precision (CV = 5.5 per cent) inter-assay precision (CV = 11 per cent), and stability of diluted, heat treated, frozen samples (at least 90 days). Plasma concentrations of LPS after sublethal (3 micrograms/kg) jugular or portal vein bolus injections of LPS rose to 4000 pg/ml and 1500 pg/ml respectively followed by a rapid phase of clearance. Peak plasma concentrations of LPS, associated with slow portal infusion, were lower than peak values associated with bolus injections, remained elevated during the infusion (2 h), but rapidly decreased after infusion was stopped. Thirty seven horses with 38 episodes of naturally occurring gastrointestinal or septicaemic disease were assayed for LPS. Eight episodes involving gastrointestinal disease and eight involving septicaemic disease were positive for LPS. It is concluded that the LAL assay is sensitive and reliable for detecting LPS in equine plasma and it may have clinical value for establishing the severity of endotoxaemia or for distinguishing between septic and non-septic conditions. Problems of rapid clearance of LPS from plasma, low concentrations, the possibility of sample contamination, and the time and method of sample procurement remain to be addressed.