Simplification of milk recording in dairy cattle for low input systems.

in Guellouz, Mustapha; Dimitriadou, Andie; Mosconi, Cesare (Eds.) Performance recording of animals. State of the art, 2004 (2004)

The simplification of recording procedures constitutes an economic alternative to reduce operational costs when national recording programs are concerned in low input production systems. A total of 54 940 ... [more ▼]

The simplification of recording procedures constitutes an economic alternative to reduce operational costs when national recording programs are concerned in low input production systems. A total of 54 940 daily milk yields from a herd of 63 Holstein cows recorded in 3 years were used in this study. The effect of reducing tests to measure the accuracy of 305 milk yields was investigated. Two methods of total milk yield computation (the Test Interval Method (TIM) and the Interpolation using Standard Lactation Curves (ISLC)) were compared based on 495 combinations of milk recording alternatives. These alternatives were based on 2 milkings/day, one alternated milking (AM/PM) and one non-alternated milking (AM or PM). All of them were used with 9 intervals between consecutive tests (3 to 11 weeks) and 11 intervals between calving date and the first test day. Results showed that the differences between the actual 305 d milk yield and milk estimated by TIM were the smallest on consecutive test days of maximum 6 weeks of intervals. Differences increased in both sides positively back to A3 and negatively toward A11. Standard estimation errors increased from 4 to 9 from A3 to A11. Phenotypic correlations decreased from .99 to .94 when intervals between the calving date and the first test day increased and this for all test methods (A3-A 11). The ISLC led to a better accuracy of milk yield estimation when intervals between consecutive tests got longer. [less ▲]

Assessment of milk yield losses and subclinical mastitis risk factors using bulk milk somatic cell counts in dairy herds

in Revue de Médecine Vétérinaire (2002), 153(4), 251-260

A prospective study, involving 21 selected dairy farms in north of Tunisia, was conducted to asses the loss of milk production due to high levels bulk tank somatic cell count and to find some relationship ... [more ▼]

A prospective study, involving 21 selected dairy farms in north of Tunisia, was conducted to asses the loss of milk production due to high levels bulk tank somatic cell count and to find some relationship between risk factors and subclinical mastitis. We found that the mean of bulk milk somatic cell count was 626 103 cell/ml. Using a simple statistical model, the average loss of milk due to levels bulk tank somatic cell count was 524 kg per cow per year. Using method of mean comparisons, risk factors associated to high levels bulk tank somatic cell count was: Livestock farming risk factors : inadequacy bedding area; inadequacy cleaning bedding and scrapping area. Milking risk factors : washing teat with a shower no adjustable flow and without wipe with individuel towel milk shift work above five per cow-herd; no stripping squirts of milk before milking; milking healthy and mastitis cows at the same time; no teat dipping. [less ▲]