The effect of extended lactation on parameters of Wood’s model of lactation curve in dairy Simmental cows

Objective This study was focused on the estimation of parameters of Wood’s model and description of the lactation curve using the cows which were lactated over 24 months on the first lactation. Methods The database included 1,333 pure-bred dairy Simmental primiparous cows which lactated for 24 month...

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Bibliographic Details
Main Authors: Tomáš Kopec, Gustav Chládek, Daniel Falta, Josef Kučera, Milan Večeřa, Oto Hanuš
Format: Article
Language:English
Published: Asian-Australasian Association of Animal Production Societies 2021-06-01
Series:Animal Bioscience
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Online Access:http://www.animbiosci.org/upload/pdf/ajas-20-0347.pdf
Description
Summary:Objective This study was focused on the estimation of parameters of Wood’s model and description of the lactation curve using the cows which were lactated over 24 months on the first lactation. Methods The database included 1,333 pure-bred dairy Simmental primiparous cows which lactated for 24 months (732 days). The initial dataset entering the procedure of assessment of parameters of Wood’s function included 35,826 milk yield records. Milk yield was recorded throughout lactation, with the earliest record taken on day 6 and the latest on day 1,348 of lactation. This dataset was used for the assessment of parameters a, b, c of Wood’s model using the non-linear statistical procedure. These parameters were estimated for different length of lactation. The assessed parameters were used for calculation of some characteristics of lactation curves. Results The lowest value of a parameter (15.2317) of Wood’s model of lactation curve was found out in lactations up to 305 days long, contrary to b and c parameters which were highest in those lactations (0.1029 and 0.0015, respectively). The maximum value of a parameter (17.4329) was found out in lactations up to 640 days long, unlike b and c parameters which were minimal in those lactations (0.0603 and 0.0010, respectively). Conclusion It can be concluded that the parameters of Wood’s model and the shape of lactation curve are changing with the growing number of milk yield records. Also, the assessed parameters revealed a significant milk production potential after 305 days of lactation.
ISSN:2765-0189
2765-0235