Relationship between cellular and whey components in buffalo milk Renata Piccinini 1 , Maria Miarelli 2 , Barbara Ferri 2 , Carmela Tripaldi 2 , Michela Belotti 1 , Valentina Dapra ` 1 , Silvia Orlandini 3 and Alfonso Zecconi 1 * 1 Universita ` degli Studi di Milano, Dip. Patologia Animale, Igiene e Sanita ` Pubblica veterinaria, Sezione di Malattie Infettive Via Celoria 10-20133 Milano Italy 2 Istituto Sperimentale per la Zootecnia, Via Salaria 31, 00016 Monterotondo (RM) Italy 3 Associazione Italiana Allevatori via Tomassetti 9-00161 Roma, Italy Received 7 February 2005 and accepted for publication 22 July 2005 High somatic cell count (SCC) affects milk quality and cheesemaking, resulting in a reduction in cheese yield and quality. In dairy cows, quarter milk samples with > 200 000 cells/ml are considered to have subclinical mastitis, while there is much uncertainty on the corresponding levels of SCC in buffalo milk. In this study 30 lactating water buffaloes were selected and SCC, differential somatic cell counts and several whey components were tested in quarter milk samples to assess the relationship between inflammation markers and milk quality. Overall 236 quarter milk samples were considered. To evaluate the relationship between cellular markers (SCC, polymorphonuclear leucocytes, PMN, and N-Acetyl-b-glucosaminidase, NAGase) and other milk components, three classes were defined (low, medium and high). Analysis of milk yield showed a significant reduction in the high class of each of the three markers chosen. Overall, the highest class was characterized by significant changes in milk composition and a lower milk quality. The presence of an inflammatory status of the udder was frequent after the first trimester of lactation and in buffaloes with two or more parturitions. This study showed that significant changes in milk components can be observed when SCC are > 400 000 cells/ml, PMN are >50% and NAGase is >100 units. These thresholds could be suggested as levels to define udder health status in buffalo cows. Keywords : Inflammation markers, SCC, NAGase, PMN. Somatic cell counts (SCC) are recognized worldwide as a measure of udder inflammation (Smith, 2002). Indeed, the increase in leucocytes in milk and in the mammary gland, as a response to the invading pathogens or to their metab- olites or toxins, leads to an increase in SCC. Therefore, SCC are used to assess udder health status, milk suitability for human consumption and to define premium/penalties on milk price (Reichmuth, 1975 ; Harmon, 1994). More- over, high SCC affects the quality and shelf-life of pasteur- ized milk (Ma et al. 2000), and impairs cheesemaking through an increase of coagulation time and moisture content, and a decrease of curd firmness, resulting in a reduction in cheese yield (Politis & Ng-Kwai-Hang, 1988a, b, c; Cooney et al. 2000). Based on the numerous data available for dairy cows, a quarter producing milk with > 200 000 cells/ml is defined as subclinically mastitic, while bacteriologically negative quarters with < 100 000 cells/ml are considered healthy (Smith, 2002; Pyorala, 2003). The scarceness of data for buffalo milk SCC in comparison with the dairy cow, leads to uncertainty about the level of SCC in buffalo milk that can be used to define the presence of an inflammation (Dhakal et al. 1992; Mahendra & Ludri, 2001; Ceron- Munoz et al. 2002; Pasquini et al. 2003). To identify the critical level, we chose to assess changes in milk compo- nents as proposed for cow milk (Hamann, 2002). This paper reports the results of a field study aimed at identify- ing suitable markers to define the inflammatory status of buffalo milk at quarter level. Materials and Methods Animals and sampling The study was performed at the Istituto Sperimentale per la Zootecnia in Rome (IZS) on 30 lactating water buffaloes *For correspondence ; e-mail : alfonso.zecconi@unimi.it Journal of Dairy Research (2006) 73 129–133. f Proprietors of Journal of Dairy Research 2006 129 doi:10.1017/S0022029905001548 Printed in the United Kingdom