Fertility and production in dairy cows

Authors: Simpson BH
Publication: New Zealand Veterinary Journal, Volume 20, Issue 10, pp 194-195, Oct 1972
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Animal production/wastage, Reproduction, Mammary gland/udder, Milk
Article class: Correspondence

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Abstract: I should greatly appreciate the opportunity to reply to Dr Dawson`s letter (N.Z. vet. J., 20: 168-9) criticizing the methods used and conclusions drawn in my article on the relationship between production and fertility in dairy cows in New Zealand (N.Z. vet. J., 20: 7). While shapes of individual lactation curves may vary widely in some countries, this is not the case in New Zealand. There is a correlation of 0.77 to 0.89 between yields at two separate monthly tests and lactation yields based on monthly testing throughout lactation (Anon., 1962). As tests during August show the poorest correlation with whole lactation production, and tests for use in “Production Ranking” were not performed until later than this, a correlation of 0.85 to 0.89 can be expected between calculated “Production Ranking” and whole lactation production. Production Ranking is, therefore, a valid measure of relative production as used in my paper…

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