Table 1 Description of the variables used in the study
Analysis | Variable | Description of the variable |
|---|---|---|
Prevalence of SCM (subclinical mastitis) and CSCM (chronic subclinical mastitis) | ||
Breed | Holstein, Ayrshire, Other. Group “other breeds” includes Finncattle, Jerseys and their crossbreds and single cows of some other breeds | |
Herd size | Average herd size (continuous variable). The average herd size is calculated as follows: (Days in feedingcow1 a + Days in feeding cow2….) divided by 365 days (or 366 days if leap year) i.e. the total amount of days within the year of recording | |
Milk yield | 305 days milk yield from each cow primiparous period (continuous variable) | |
Parity | Parity 1 to ≥4 (categorical variable) | |
Production type | Organic, conventional | |
Quartileb | Quartile of the year—Jan–Mar, Apr–Jun, Jul–Sept, Oct–Dec | |
Region | Geographical region of Finland—South, West, North, East. Every herd belonged to one of the 22 regional ProAgria Agricultural units in study years of 1991, 2001 and 2010. These units were divided according to province borders (in 2012) into four geographic regions | |
Type of the stallc | Tie-stall, free-stall, free-stall with AMS (automatic milking system) | |
Year | Year of the data recording—1991, 2001, 2010 | |
SCC | ||
Cow level | Breed | Holstein, Ayrshire, Other. Group “other breeds” includes Finncattle, Jerseys and their crossbreds and single cows of some other breeds |
Herd size | Average herd size (continuous variable). The average herd size was calculated as follows: (Days in feedingcow1 a + Days in feedingcow2….) divided by 365 days (or 366 days if leap year) i.e. the total amount of days within the year of recording | |
Milk yield | 305 days milk yield from the first lactation period (continuous variable) | |
Parity | Parity 1 to ≥4 (continuous variable) | |
Production type | Organic, conventional | |
Quartile | Quartile of the year—Jan–Mar, Apr–Jun, Jul–Sept, Oct–Dec | |
Region | Geographical region of Finland—South, West, North, East. Every herd belonged to one of the 22 regional ProAgria Agricultural units in study years of 1991, 2001 and 2010. These units were divided according to province borders (in 2012) into four geographic regions | |
Type of stallb | Tie-stall, free-stall, free-stall with AMS (automatic milking system) | |
Year | Year of the data recording—1991, 2001, 2010 | |
Herd level | Herd size | Average herd size (continuous variable). The average herd size was calculated as follows: (Days in feeding acow1 + Days in feedingcow2….) divided by 365 days (or 366 days if leap year) i.e. the total amount of days within the year of recording |
Herd milk yield | Average annual milk yield of the herd (continuous variable). Milk yield of the herd was calculated as follows: (Milk kg of the yearcow 1 + Milk kg of the yearcow 2 + Milk kg of the yearcow 3 + Milk kg of the year cow 4..)/average herd size | |
Average parity, herd | Average parity of the cows in the herd (continuous) | |
Region | Geographical region of Finland—South, West, North, East. Every herd belonged to one of the 22 regional ProAgria Agricultural units in study years of 1991, 2001 and 2010. These units were divided according province borders (in 2012) into four geographic regions | |
Type of the stallb | Tie-stall, free-stall, free-stall with AMS (automatic milking system) | |
Year | Year of the data recording—1991, 2001 and 2010 | |