Effect of somatic cell count on composition and hygiene indicators of bulk tank milk

Abstract

This study evaluated the effect of somatic cell count (SCC) on composition and hygienic quality of dairy herd bulk tank milk -specifically, the effect of SCC of bulk tank of dairy herds on composition (fat, protein, total solids, nonfat dry solids) and on total bacterial count (TBC), psychrotrophic count (PC) and coliform count (CC) were evaluated. A total of 230 dairy herds located south of Minas Gerais and west of São Paulo were selected based on SCC geometric mean obtained from five monthly analyses preceding the start of the sampling. The dairy farms were classified according to SCC in three groups: low (< 250,000 cells/mL, n = 84), medium (> 250,000 and < 750,000 cells/mL, n = 79) and high SCC (> 750,000 cells/mL, n = 67). After herd selection, bulk tank milk samples were collected every 14 days for three months totaling 1380 samples, which were subjected to analysis of composition, TBC, PC, and CC. A decrease of TBC and CC was observed in herds with low SCC; however, herds with medium and high SCC had an increase in fat, crude protein, and total solids contents. A medium correlation was observed between TBC and PC (r = 0.6215), and also between PC and CC (r = 0.3692). Based on hygiene indicators and milk composition, a low and negative correlation between TBC and fat (r = -0.0585), PC and fat (r = -0.0585), and PC and total solids (r = -0.0662) was observed. Dairy herds with SCC < 250,000 cells/mL had higher bulk tank milk hygienic quality; however, considering the composition, herds with higher SCC produced higher milk fat and protein concentration. Keywords: Microbiological culture. Diagnostic. Microorganisms. Milk quality. Sanity. ResumoEste trabalho avaliou o efeito da contagem de células somáticas (CCS) na composição e na qualidade higiênica do leite de tanque de rebanhos leiteiros. Especificamente, foram avaliados o efeito da CCS do tanque de rebanhos leiteiros na composição (gordura, proteína, sólidos totais, extrato seco desengordurado) e nas contagens bacteriana total (CBT), de psicrotróficos (CP) e de coliformes (CC). Um total de 230 rebanhos leiteiros localizados no sul de Minas Gerais e oeste de São Paulo foram selecionados com base na média geométrica da CCS obtida de cinco análises mensais anteriores ao início das coletas das amostras. As fazendas foram classificadas de acordo com a CCS em três grupos: baixa (< 250.000 células/mL, n = 84), média (> 250.000 e < 750.000 células/mL, n = 79) e alta CCS (> 750.000 células/mL, n = 67). Após a seleção dos rebanhos, amostras de leite do tanque foram coletadas a cada catorze dias durante três meses, totalizando 1.380 amostras, as quais foram submetidas às análises de composição, CBT, CP e CC. Uma redução da CBT e da CC foi observada em rebanho com baixa CCS; entretanto, rebanhos com média e alta CCS tiveram aumento nos teores de gordura, proteína bruta e sólidos totais. Uma média correlação foi observada entre CBT e CP (r = 0,6215) e também entre CP e CC (r = 0,3692). Com base nos indicadores de higiene e na composição do leite, foi observada ...

Effect of heat stress on udder health of dairy cows

“…A bulk tank SCC greater than a target level (e.g. 250 000 cells/ml) often indicates underlying subclinical mastitis (Lievaart et al ., 2007; Macedo et al ., 2018). Regrettably, and as we have already said, numerous studies have recorded higher levels than this.…”

“…Various time series studies have reported bulk tank SCC above the locally accepted level, e.g. 250 000 cells/ml, in different regions and countries in the world (Lievaart et al ., 2007; Kelly et al ., 2009; Suriyasathaporn et al ., 2012; Hashemzadeh and Khalajzadeh, 2014; DeLong et al ., 2017; Aghamohammadi et al ., 2018; Macedo et al ., 2018). SCC also increases with environmental THI (Nasr and El-Tarabany, 2017), reducing milk value (St-Pierre et al ., 2003; Rhoads et al ., 2013).…”

“…Bulk tank SCC is used as a milk payment parameter to improve milk quality in many countries (Barkema et al ., 2013; Busanello et al ., 2017). In Brazil, Lopes and Lima (2018) followed bulk milk samples of 352 dairy farms and reported a negative correlation between SCC and lactose, non-fat dry milk extract, casein and percent of casein in total protein concentrations, conversely, increased SCC is associated with increased contents of total bacterial count, fat and minerals (Lopes and Lima, 2018; Macedo et al ., 2018).…”

Effects of some environmental factors on somatic cell count and milk chemical composition in cow bulk tank milk

“…Different result was reported by Ribas et al (2014), as they observed SNF with increasing SCC increased. Macedo et al (2018) also found that SNF were higher in herds with SCC threshold higher than 250x10 3 cells/ml. Variation in the diffrent results may be due to differences in diet, parity and season of the experiment, management, etc.…”

Evaluation of The Effects of Milking Hygiene and Sanitation Education on Total Bacterial and Somatic Cell Number of Bulk Tank Milk in Dairy Cattle Breeding

“…High SCC was affected by age of the cow, age of lactation, stress, season, nutrition, observance of hygiene rules and mastitis. The levels of SCC and TVC provide valuable information on the hygienic conditions during various steps of milk production on the farm (Cedden et al 2002;Eyduran et al 2005;Macedo et al 2018;Ginestreti et al 2020). Consumers need to be able to source raw milk from farmers that have adopted a high level of good animal husbandry practices and manufacturing practices that can reduce potential food safety hazards to very low levels (Berge and Baars 2020;Singhal et al 2020).…”