Subclinical intramammary infection does not affect bovine milk ethanol stability

Abstract

The present study hypothesized that intramammary infection (IMI) might reduce milk ethanol stability (MES), mainly when IMI is caused by major pathogens. Thus, this study evaluated the effect of IMI on bovine MES using a natural exposure experimental design. Ninety-four lactating cows from five dairy herds were selected once they were determined to have an IMI, based on milk bacteriological culturing with positive isolation and somatic cell count (SCC) > 200×10 3 cells/mL in two out of three composite milk samples collected during three consecutive weeks. After selection, cows were sampled a second time (within two weeks) for evaluation at mammary quarter level (n = 326): milk yield (kg/quarter/day), MES, composition (fat, protein, lactose, casein, total solids and solids-non-fat), and bacteriologic culture. The effect of subclinical mastitis on MES was tested by two models: 1) comparison of healthy vs. infected quarters; and 2) comparison of contralateral mammary quarter within cow. The only milk composition variable associated with MES was lactose (r = 0.18; P < 0.01). Subclinical IMI did not affect MES when the comparison was performed using both models (1 and 2). Likewise, MES did not change when infected quarters were sorted into two groups of pathogens (major, minor and infrequent; and contagious, environmental, minor and infrequent) and compared with healthy mammary quarters. Considering the results of both models, subclinical IMI did not affect MES of dairy cows. Keywords: Alcohol test. Casein. Ionic calcium. Mastitis. ResumoNeste trabalho investigou-se a hipótese de que a infecção intramamária (IIM) poderia reduzir a estabilidade do leite ao etanol (ELA), principalmente quando a IIM é causada por agentes primários. Assim, em um experimento de exposição natural, foi avaliado o efeito da IIM sobre a ELA em bovinos. Noventa e quatro vacas em lactação de cinco rebanhos leiteiros foram selecionadas por apresentar IIM, segundo resultados de cultura bacteriológica de amostras compostas de leite (isolamento positivo) e contagem de células somáticas (CCS) > 200×10 3 células/mL em pelo menos duas de três coletas semanais consecutivas. Após essa seleção, as vacas foram amostradas pela segunda vez (dentro de duas semanas) para avaliação da IIM em amostras de leite coletadas por quarto mamário (n = 326): produção de leite (kg/quarto/dia), ELA, composição (gordura, proteína, lactose, caseína, sólidos totais e sólidos não gordurosos) e cultura bacteriológica. O efeito da mastite subclínica sobre a ELA foi testada por dois modelos: 1) comparação de quarto sadio versus infectado; e 2) comparação de quartos mamários contralaterais. A única variável de composição do leite associada à ELA foi a lactose (r = 0,18; P < 0,01). A IIM subclínica não afetou a ELA quando a comparação foi realizada utilizando-se os dois modelos (1 e 2); bem como a ELA não foi alterada quando os quartos infectados foram classificados em grupos de agentes patogênicos (primários, secundários e infrequentes; ou contagiosos, ambientais, secundá...

Characterization of variables related to high stability of raw cow milk

“…This increased permeability results in ethanol instability due to salt imbalance. Martins et al (2019), who evaluated the effect of subclinical mastitis on the ethanol stability of milk, found lactose to be the only milk composition variable that was positively correlated with stability (r = 0.18).…”

Ionic calcium variation in normal, acidic, alkaline and unstable non‐acidic bovine milks and its relationship with alcohol stability

“…Furthermore, seasonal variations were found to exert an influence on iCa levels. Martins (2022) observed that milk from cows during the summer exhibited higher iCa content compared to the winter in Brazil. Consequently, alcohol stability was compromised during the summer months.…”

Interrelationships Between Milk Constituents, Protein Profile, Genotypes of Kappa-Casein Gene and Ethanol Stability of Cow's Milk

“…Heat stress, reduction in dietary cation-anion differences, and ruminal and metabolic acidosis have all been linked to decreased milk ethanol stability, according to Marques et al (2011) and Martins et al (2015). In Brazil and other nations that regularly utilize ethanol tests for milk evaluation, the incidence of unstable non-acid milk can therefore be strongly linked to dietary imbalance, digestive issues, as well as hereditary and environmental circumstances, but not to subclinical intramammary infections (Martins et al, 2018).…”

“…The reasons that predispose to the production of unstable milk are unknown. Several factors linked to metabolic and/or nutritional diseases, digestive difficulties, as well as genetic and environmental variables that can alter milk synthesis and milk components, have been identified in previous investigations (Martins et al, 2018).…”