How to translate text using browser tools
3 August 2023 Study of persistency of lactation and survival of Iranian Holstein dairy cattle using random regression model
Ali Ashrafian, Nasser Emam Jomeh Kashan, Mokhtar Ali Abbasi, Ali Asghar Sadeghi, Mohammad Rokouei
Author Affiliations +
Abstract

The aim of this paper is to investigate whether characteristics of the first lactation (FL) curve of Iranian Holstein cows are associated with survival. Cows with least 10 test-days of milk production in their FL were used. The persistency of lactation (PL) and survival were estimated using a random regression model by restricted maximum likelihood with the ECHIDDNA software. We also used the Wood model to parameterize each individual lactation curve and then analyzed various curve characteristics using an animal model. The predicted breeding value (EBV) of the characteristics of the lactation curve of the cows from day 40 to 305 was predicted. The EBV of the production range (PR) and the slope of line in increasing phase (m40,Peak) of production curve of sires with higher survival EBV were lower than other sires (P < 0.05). The estimates of PL were independent of survival estimate. Therefore, the PR from 40th day after calving can be considered as a definition of PL because the lower the PR, the flatter is the milk production curve. Genetic evaluation of young bulls for survival needs the data of death or culling of their daughters. Therefore, the bulls can genetically be evaluated for survival according to the PL and m40,Peak of FL information of their daughters.

Ali Ashrafian, Nasser Emam Jomeh Kashan, Mokhtar Ali Abbasi, Ali Asghar Sadeghi, and Mohammad Rokouei "Study of persistency of lactation and survival of Iranian Holstein dairy cattle using random regression model," Canadian Journal of Animal Science 103(4), 406-415, (3 August 2023). https://doi.org/10.1139/cjas-2023-0007
Received: 26 January 2023; Accepted: 21 July 2023; Published: 3 August 2023
JOURNAL ARTICLE
10 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

KEYWORDS
Holstein
lactation persistency
production range
survival
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top