Three times a day milking: effects on milk production, reproductive efficiency, and udder health.

Dairy Herd Improvement records from 14 Holstein herds in San Joaquin County, CA were studied. Seven herds were milked three times a day, the other 7 twice a day. Three times daily milking significantly increased yield of 305-d fat-corrected milk.

Canine hip dysplasia in German Shepherd Dog-Greyhound crossbreeds.

Nineteen German Shepherd Dog-Greyhound crossbreeds in 7 litters were evaluated by pathoanatomic and/or radiographic examination of their pelves when 12 to 24 months old (mean, 19 months). The prevalence of hip dysplasia in the crossbreeds was 42% (8/19). The prevalence of hip dysplasia in purebred German Shepherd Dog half-siblings in 16 litters produced by parents of the crossbreeds when mated to other German Shepherd Dogs was 35% (16/46).

Factors affecting milk yield and reproductive performance.

Dairy Herd Improvement testing records of 201 dairy herds of sizes from under 100 to over 1000 cows and herd average milk yields from under 5,000 to over 10,000 kg were studied. Average days to first postpartum breeding tended to be less in herds of over 500 cows. Herds of 300 to 600 cows had highest production per cow.

Genetic analysis of California mastitis test records. II. Score for resistance to elevated tests.

A lactation score for rating individual cows for their apparent resistance to elevation of California Mastitis test is described. The score uses the first nine monthly California Mastitis Tests weighted by the number and position of elevated coded tests. California mastitis test readings of negative and trace were coded "normal" and 1, 2, or 3 "elevated".

Genetic analysis of California mastitis test records. I. Coded tests.

A sample of 15,965 Holstein lactation records having California Mastitis Test scores for at least the first 9 mo of standard Dairy Herd Improvement production testing were studied for the effects of sire, parity, and year and month of calving. California Mastitis Test readings of "negative" or "trace" were coded normal while readings of "1", "2", or "3" were coded elevated. The frequency of elevated tests increased as parity increased.