Genomic mapping of non-coagulation of milk in the Finnish Ayrshire

K Elo,P Anttila,V Vilva,M Ojala,A.-M Tyrisevä

doi:10.22358/jafs/74193/2007

Abstract

The objective of this study was to identify chromosomes affecting non-coagulation of milk in the Finnish Ayrshire. All autosomes were analysed using two pools of DNA samples. Samples from cows milking non-coagulating (NC) and well-coagulating (E) milk were pooled. Pools included 33 NC- and 49 E-animals and they were genotyped using 184 microsatellite markers. Two candidate chromosomes, 24 and 28, were selected based on differences between pools. Chromosomes 24 and 28 were studied using 14 microsatellite markers, individual genotyping and daughter design. Nonparametric interval mapping involved eighteen sire families with a total of 480 daughters. In interval mapping, chromosome 24 associated to NC-milk in one family.

Highlights

The average percentage of milk used in cheese production is approximately 50% in the European Union when calculated from production statistics using a 10/L milk to cheese yield ratio (Eurostat, 2006)
Our studies have shown that in the Finnish Holstein-Friesian and in the Finnish Ayrshire about 12 and 30% of cows produce poorly coagulating milk (Tyrisevä et al, 2004), and about 1% of Holstein-Friesian and 10% of Ayrshire cows produce non-coagulating (NC) milk (Ikonen, 2000; Ikonen et al, 2004; Tyrisevä et al, 2004)
One milk sample was collected per cow and milk coagulation time (R), curd firming time (K20) and curd firmness (E30) were measured with computerized renneting meter as described by Ikonen et al (2004)

Summary

Introduction

The average percentage of milk used in cheese production is approximately 50% in the European Union when calculated from production statistics using a 10/L milk to cheese yield ratio (Eurostat, 2006). The high percentage of milk used in cheese production suggests that in many European countries the improvement of raw milk for cheese making should be economically well-motivated. In addition to technological improvements in cheese industry, breeding and management of dairy cattle provide important tools to improve quality of milk for cheese making. Milk coagulation properties (MCP) are known to play important role in cheese production (Ikonen, 2000; Lucey, 2002). Milk coagulation is dependent on environmental and genetic factors of dairy cows (Ikonen, 2000). GENOMIC MAPPING OF NONCOAGULATION OF MILK technological factors in cheese making affect coagulation (Lucey, 2002; Nájera et al, 2003)

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Conclusion