Tz. PEEVA and Y. ILIEVA
Agricultural Institute, BG-9700 Shumen, Bulgaria
PEEVA, Tz. and Y. ILIEVA, 2007. Type rating due to age, stage of lactation and milk level in buffalo cows. Bulg. J. Agric. Sci.,13: 483-488
The aim of the present study was to investigate the influence of some environmental factors on the sub ratings and over-all rating of buffalo cows. Ratings of 819 buffalo cows, classified a total 2457 times by one and the same classifier were used.
To asses the effect of the different factors was employed a linear model with the following factors: age, stage of lactation and level of milk yield of the buffalo cows.
Lactation numbers were used as a measure of age and ratings grouped into lactations 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. Ratings were also grouped according to stage of lactation: (1) from day of calving to 90 days; (2) 91 days to 210 days and (3) 211 days to the next calving. According to the level of milk yield ratings were grouped into 4 levels: (1) to 1500 kg; (2) 1501 kg to 1800 kg; (3) 1801 kg to 2100 kg and (4) higher then 2101 kg.
Considerable and significant effect on the general appearance, body capacity and mammary system plays the age (lactation) of the buffalo cows; on dairy character, mammary system and over-all rating - the level of milk yield and on mammary system and over-all rating - the stage of lactation period.