Effect of summer season on milk protein fractions in Holstein cows
- 1 March 2015
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 98 (3), 1815-1827
- https://doi.org/10.3168/jds.2014-8788
Abstract
Milk characteristics are affected by heat stress, but very little information is available on changes of milk protein fractions and their relationship with cheesemaking properties of milk. The main objective of the study was to evaluate the effect of hot season on milk protein fractions and cheesemaking properties of milk for Grana Padano cheese production. The study was carried out in a dairy farm with a cheese factory for transforming the milk to Grana Padano cheese. The study was carried out from June 2012 to May 2013. Temperature and relative humidity of the inside barn were recorded daily during the study period using 8 electronic data loggers programmed to record every 30 min. Constant managerial conditions were maintained during the experimental periods. During the experimental period, feed and diet characteristics, milk yield, and milk characteristics were recorded in summer (from June 29 to July 27, 2012), winter (from January 25 to March 8, 2013), and spring (from May 17 to May 31, 2013). Milk yield was recorded and individual milk samples were taken from 25 cows selected in each season during the p.m. milking. Content of fat, proteins, caseins (CN), lactose and somatic cell count (SCC), titratable acidity, and milk rennet coagulation properties were determined on fresh samples. Milk protein fraction concentrations were determined by the sodium dodecyl sulfate-PAGE. Data were tested for nonnormality by the Shapiro-Wilk test. In case of nonnormality, parameters were normalized by log or exponential transformation. The data were analyzed with repeated measures ANOVA using a mixed model procedure. For all the main milk components (fat, protein, total solids, and solids-not-fat), the lowest values were observed in the summer and the greatest values were observed in the winter. Casein fractions, with the exception of γ-CN, showed the lowest values in the summer and the greatest values in the winter. The content of IgG and serum albumin was greater in summer than in the winter and spring. A mild effect of season was observed for milk SCC, with greater values in summer than in the winter and spring. A worsening of milk coagulation properties was observed in summer season. The alteration of cheesemaking properties during hot season seems strictly linked with changes of milk protein fractions mainly with the decrease of αS-CN and β-CN and the increase of undefined proteinsKeywords
Funding Information
- Italian Ministry of Agriculture, Food and Forestry (MiPAAF), FILIGRANA project (25741/7303/11-01/12/2011)
This publication has 32 references indexed in Scilit:
- The effects of heat stress in Italian Holstein dairy cattleJournal of Dairy Science, 2014
- Seasonal variations in the composition of Holstein cow’s milk and temperature–humidity index relationshipAnimal, 2014
- RUMINANT NUTRITION SYMPOSIUM: Ruminant Production and Metabolic Responses to Heat Stress1,2Journal of Animal Science, 2012
- Metabolic and hormonal acclimation to heat stress in domesticated ruminantsAnimal, 2010
- Metabolic conditions of lactating Friesian cows during the hot season in the Po valley. 1. Blood indicators of heat stressInternational Journal of Biometeorology, 2007
- Effects of melatonin on the yield and composition of milk from grazing dairy cows in New ZealandJournal of Dairy Research, 2006
- Effects of atropine on plasma amino acid profiles and on the synthesis of individual milk proteins in dairy cows fed with pastureJournal of Dairy Research, 2003
- Comparison of lactational responses of dairy cows in Georgia and Israel to heat load and photoperiodAnimal Science, 2002
- Effects of the hot season on milk protein fractions in Holstein cowsAnimal Research, 2002
- Producing specific milks for speciality cheesesProceedings of the Nutrition Society, 2001