Factors Associated with Semen Collection Method and Its Influence on Seminal Parameters and Fertility of Stallions in AI Programs
H Sieme,^1,3 E Klug,² N Arras,^1,2 and S Weinrich^1,2
1 State Stud of Lower Saxony , Celle, Germany, ²Clinic for horses, Veterinary School Hanover, Germany and
³Institute for Reproductive Medicine, Veterinary School Hanover, Germany

To study effect of factors associated with semen collection on stallion spermatozoa vitality the following conditions were kept constant. Semen was collected from 36 warmblood bred stallions 4-18 years of age on monday, wednesday and friday starting october to end of january during the routine freezing program in state stud of Lower Saxony. Stallion semen was collected with artificial vagina (model: Hannover) and the use of a phantom with a teaser mare standing in a box in front of the phantom. Stallions were guided by always the same specialized technician and even collected by always the same A.I.-technician. Immediately after the individual stallion enters collection room timespan (sec.) was measured until semen was collected and additionaly amount of jumps on phantom (n) were counted until ejaculation. Twelve ejaculates per stallion were analysed for percentages of the following parameters seminal gel free volume (VOL), sperm concentration (CONC), total sperm count (TSC), motility immediately after collection and after storage for 24h at +5°C. (MOT, MOT24h), eosin-nigrosin live stained spermatozoa (ENL), eosin-nigrosin pathological stained spermatozoa (ENP), swollen spermatozoa after incubation in hypoosmotic medium (HOS), live and membrane intact spermatozoa after carboxyfluoresein/propidium iodide stain (CFDA/PI) and intact spermatozoa after chlortetracyclin stain (CTC). Data were statistically analysed using SASÒ software and spearman correlation-coefficient (s.Table 1).

Table 1. Influence of duration of semen collection procedure and amount of jumps until ejaculation on stallion semen collected under constant conditions

* = p£0,05, ** = p£0,01, *** = £0,001

Use of A.I.-stallions as teasers (n=11; pregnancy rate PR = 69,5% ±17,12, foaling rate FR = 57,3% ±13,39) resulted in a significant decrease in fertility (p£0,05) in comparison to A.I.-stallions without use for teasing (n=77; PR = 78,3% ±15,87, FR = 64,1% ±11,51).

To study the effect of of semen collection interval stallions were classified in 3 groups. Group A (n=32) consists of stallions with discontinious semen collection interval as semen was required, group B (n=68) with an once daily semen collection and group C (n=14) with intervals between 1 and 2 collections daily. PR and FR are in group A 70,5% ±16,04, 58,9 ^b % ±15,88; B 75,2% ±9,11, 65,6 ^a % ±9,59 and C 71,4% ±8,14, 61,7 ^b % ±8,33 (a:b p£0,05).