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Modelling Extended Lactations in Polish Holstein–Friesian Cows

SIMPLE SUMMARY: Mathematical models of lactation curves are functions that describe milk production on each day of lactation. These models are able to predict milk yields as well as provide valuable information applicable in breeding and management decisions. The aim of the present study was to exam...

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Autores principales: Otwinowska-Mindur, Agnieszka, Ptak, Ewa, Makulska, Joanna, Jarnecka, Olga
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8388494/
https://www.ncbi.nlm.nih.gov/pubmed/34438634
http://dx.doi.org/10.3390/ani11082176
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author Otwinowska-Mindur, Agnieszka
Ptak, Ewa
Makulska, Joanna
Jarnecka, Olga
author_facet Otwinowska-Mindur, Agnieszka
Ptak, Ewa
Makulska, Joanna
Jarnecka, Olga
author_sort Otwinowska-Mindur, Agnieszka
collection PubMed
description SIMPLE SUMMARY: Mathematical models of lactation curves are functions that describe milk production on each day of lactation. These models are able to predict milk yields as well as provide valuable information applicable in breeding and management decisions. The aim of the present study was to examine different shapes of lactation curves for milk traits (i.e., milk, fat, protein and lactose yields and urea content in milk) modelled by the Wilmink function and by linear or squared functions between 306 and 400 days in milk (DIM). The results suggested that the course of extended lactations could be modelled by a nonlinear model, for example, the Wilmink function, for up to 305 DIM, and the linear or squared function could be more appropriate afterwards. ABSTRACT: The objectives of this study were (1) to examine different shapes of lactation curves for milk, fat, protein and lactose yields and urea content in milk fitted by the Wilmink function using the test-day (TD) records and (2) to find the function that best describes test-day records beyond 305 days in milk (DIM) for Polish Holstein–Friesian cows. The data were 6,955,768 TD records from the 702,830 first six lactations of 284,193 Polish Holstein–Friesian cows. Cows calved in 19,102 herds between 2001 and 2018. The following functions were fitted to TD data from each lactation: (1) Wilmink model fitted to the whole lactation, (2) Wilmink model fitted to TD records from 5 to 305 DIM and linear function fitted to TD records from 306 to 400 DIM, (3) Wilmink model fitted to TD records from 5 to 305 DIM and squared function fitted to TD records from 306 to 400 DIM. The present study showed that urea content in milk was modelled slightly worse than other milk traits. The results suggested that the course of lactation could be successfully modelled by a nonlinear model, for example, the Wilmink function, for up to 305 DIM, and by the linear or squared function afterwards.
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spelling pubmed-83884942021-08-27 Modelling Extended Lactations in Polish Holstein–Friesian Cows Otwinowska-Mindur, Agnieszka Ptak, Ewa Makulska, Joanna Jarnecka, Olga Animals (Basel) Article SIMPLE SUMMARY: Mathematical models of lactation curves are functions that describe milk production on each day of lactation. These models are able to predict milk yields as well as provide valuable information applicable in breeding and management decisions. The aim of the present study was to examine different shapes of lactation curves for milk traits (i.e., milk, fat, protein and lactose yields and urea content in milk) modelled by the Wilmink function and by linear or squared functions between 306 and 400 days in milk (DIM). The results suggested that the course of extended lactations could be modelled by a nonlinear model, for example, the Wilmink function, for up to 305 DIM, and the linear or squared function could be more appropriate afterwards. ABSTRACT: The objectives of this study were (1) to examine different shapes of lactation curves for milk, fat, protein and lactose yields and urea content in milk fitted by the Wilmink function using the test-day (TD) records and (2) to find the function that best describes test-day records beyond 305 days in milk (DIM) for Polish Holstein–Friesian cows. The data were 6,955,768 TD records from the 702,830 first six lactations of 284,193 Polish Holstein–Friesian cows. Cows calved in 19,102 herds between 2001 and 2018. The following functions were fitted to TD data from each lactation: (1) Wilmink model fitted to the whole lactation, (2) Wilmink model fitted to TD records from 5 to 305 DIM and linear function fitted to TD records from 306 to 400 DIM, (3) Wilmink model fitted to TD records from 5 to 305 DIM and squared function fitted to TD records from 306 to 400 DIM. The present study showed that urea content in milk was modelled slightly worse than other milk traits. The results suggested that the course of lactation could be successfully modelled by a nonlinear model, for example, the Wilmink function, for up to 305 DIM, and by the linear or squared function afterwards. MDPI 2021-07-22 /pmc/articles/PMC8388494/ /pubmed/34438634 http://dx.doi.org/10.3390/ani11082176 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Otwinowska-Mindur, Agnieszka
Ptak, Ewa
Makulska, Joanna
Jarnecka, Olga
Modelling Extended Lactations in Polish Holstein–Friesian Cows
title Modelling Extended Lactations in Polish Holstein–Friesian Cows
title_full Modelling Extended Lactations in Polish Holstein–Friesian Cows
title_fullStr Modelling Extended Lactations in Polish Holstein–Friesian Cows
title_full_unstemmed Modelling Extended Lactations in Polish Holstein–Friesian Cows
title_short Modelling Extended Lactations in Polish Holstein–Friesian Cows
title_sort modelling extended lactations in polish holstein–friesian cows
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8388494/
https://www.ncbi.nlm.nih.gov/pubmed/34438634
http://dx.doi.org/10.3390/ani11082176
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