Age-related changes in quality and fertility of porcine semen.

The aim of this study was to investigate the effect of boar age on quality traits and fertility of liquid-stored semen. Boars were allocated into 3 age groups: 7-10 months (young), 18-33 months (mature), 51-61 months (old). Ejaculates of > 200x10(6) sperm/ml and 85% total motile sperm were extended to 30x10(6) sperm/ml, stored at 17-18 °C and used within 12-24 h for artificial insemination (AI) of 2062 multiparous sows.

Effects of experimental challenge of ewes with Mannheimia haemolytica on subsequent milk composition.

The objective was to describe the physicochemical changes during the early phase of subclinical mastitis and to associate them with pathological findings. A Mannheimia haemolytica strain was deposited into one teat duct of 25 ewes and the clinical, bacteriological, cytological, physicochemical (pH, milk composition), gross-pathological and histological findings were subsequently recorded. The organism was consistently isolated from samples of teat duct material (140/150) but not from mammary secretion (50/150).

Differences in susceptibility to Mannheimia haemolytica-associated mastitis between two breeds of dairy sheep.

We used a Mannheimia haemolytica isolate to study differences in susceptibility to experimental mastitis between two breeds of dairy sheep. The isolate was deposited into the teat duct of Karagouniko (K, n=8) or Frisarta (F, n=8) ewes. The animals were monitored by means of clinical, bacteriological, cytological and pathological methods.