A Comparison of Bimonthly and Quarterly Testing with Monthly Testing for Estimating Dairy Cattle Production

Accuracy of predicting milk yield from alternative milk recording schemes

“…This is similar to previous studies with simulated data which showed that A4 recording schemes were twice as accurate as A12 recording schemes for predicting actual milk yield (Erb et al, 1952). In the present study the lower percentage of A12-predicted yields that were within ±200 kg of A4-predicted yields when compared with the A8 scheme agrees with reports from Bayley et al (1952). They stated that 12·5% of the differences between A12 and A4 were greater than proportionately 0·10 of the mean compared with 2·2% between A8 and A4-predicted lactation yields.…”

“…Tests at all stages of lactation will give a more accurate estimate of 305-day yield than tests from only the early stages of lactation. Bayley et al (1952) reported that the frequency of large errors in A8 milk recording was twice as prevalent in cows fi rst tested in the second month of lactation compared with cows fi rst tested in the fi rst month of lactation. Contrary to these conclusions, the recording scheme with the fi rst test in the 2nd month (A8-246) was slightly more accurate than the A8-135 scheme in the present study.…”

The Precision of Some Sampling Methods of Estimating the Milk, Butterf at, Solids Not Fat, and Crude Protein Yield of Dairy Cows

“…ALEXANDER and YADP (1) found that testing three times during the lactation the second, sixth, and tenth month, or testing only twice during the lactation, the second and tenth or the fourth and eighth month gave "sufficiently" accurate results to merit consideration as a means of reducing the costs of testing. BAYLAY et al (6) found the average percentage error in milk yield for bi-monthly and quarterly testing to be 3.0 and 5.0°/o, respectively, as compared to monthly tests representing the true yield. Fat yields varied 4.0 and 6.0 O/o for the same comparisons.…”

Συμβολή Στην Προώθηση Της Γενετικής Βελτίωσης Του Προβάτου Στην Ελλάδα

“…Οι Flamant and Barillet (1982) υπολόγισαν το κόστος στο 4-5% για τα πρόβατα της φυλής Lacaune, ενώ το αντίστοιχο για τις αγελάδες ήταν περίπου 2%. (Gifford, 1930, Bayley et al, 1952, Castle and Searle, 1961, Anderson et al, 1989, είτε στην καταγραφή των αποδόσεων του ενός μόνο από τα δύο αρμέγματα του εικοσιτετραώρου (πρωινό ή βραδινό). Το τελευταίο λαμβάνει χώρα με την εφαρμογή της εναλλακτικής (ΑΤ) ή της διορθωμένης (AC) μεθόδου (Porzio, 1953, McDaniel, 1969, Dickinson and McDaniel, 1970, Smith and Pearson, 1981, Barillet, 1985, Maria and Gabiña, 1992, Barillet, 1997, Sanna et al, 1998, Drobnic et al, 2001.…”