Acid-base balance of dairy cows and its relationship with alcoholic stability and mineral composition of milk

Abstract

Pesq. Vet. Bras. 34(5):398-402, maio 2014 398 RESUMO.-[Equilíbrio ácido-base de vacas leiteiras e sua relação com a estabilidade alcoólica e composição mineral do leite.] Esse trabalho teve como objetivo associar a ocorrência de distúrbios ácido-base com a estabilidade alcoólica do leite de animais a campo, bem como avaliar diferenças entre a composição mineral de leites estáveis e instáveis ao álcool. A amostragem compreendeu 96 vacas leiteiras, das quais o leite e o sangue correspondente de cada animal foram coletados. A composição mineral entre leites estáveis e instáveis ao álcool foi diferente e também pode estar relacionada aos distúrbios ácido-básicos. A quantidade média de fosfato foi menor no leite instável ao álcool, enquanto a de potássio foi maior. A frequência de amostras de leite com instabilidade alcoólica foi maior nas vacas com distúrbios ácido--básicos. A alcalose respiratória foi o desequilíbrio mais observado.TERMOS DE INDEXAÇÃO: Gasometria, alcalose, eletrólitos, leite instável não ácido. INTRODUCTIONAcid-base balance is vital to maintaining an animal's blood pH and its health state (Fetmann 2007). In dairy cows, changes in this system may be accompanied by electrolyte disturbances that can influence the composition and ionic balance of the milk (Marques 2011).Oscillations in some milk components, such as mineral balance, lactose, urea and free calcium may be related to alcoholic stability. This causes other variables, besides microbiological acidity, to influence the alcohol/alizarol test and there may be unnecessary rejection of raw milk at the time of data collection or receipt by the industry. Unstable milk in the alcohol test, and without acidity of microbiological origin, is referred to as unstable non-acid milk (UNAM) (Lucey & Horne 2009, Molina et al. 2001.UNAM is a current problem in many countries that still use the alcohol test to measure the quality of milk, such as Brazil, Uruguay, Cuba and Argentina. The instability of milk in alcohol also generates technological problems in the manufacture of creamy liqueurs, such as 'neck plug' and redu-

Estabilidade Do Leite Ao Álcool Ainda Pode Ser Um Indicador Confiável?

“…Vacas com alcalose respiratória têm alta probabilidade de produzir leite com instabilidade alcoólica (14) . Para compensar esse distúrbio, o organismo do animal aumenta a excreção de bicarbonato no sangue.…”

Seasonal variation, method of determination of bovine milk stability, and its relation with physical, chemical, and sanitary characteristics of raw milk

“…Feed restriction (Gabbi et al, 2013, excess of fiber in the diet (Barchiesi-Ferrari et al, 2007), or nutrient imbalance (Marques et al, 2010b) negatively affect milk stability, although the underlying mechanisms are not completely determined; however, it seems that metabolism disturbance leading to metabolic acidosis (Fagnani et al, 2014;Marques et al, 2011) and higher permeability of the tight junctions of epithelial mammary cells is probably enrolled as a causal factor of the low milk stability.…”

“…Differences in lactose and protein contents between milk with high stability and unstable milk are partially due to inadequate supply of nutrients, feeding of low-quality forages, metabolic or ruminal disturbances, and poor hygienic-sanitary characteristics of milk (Zanela et al, 2006;Barchiesi-Ferrrari et al, 2007;Marques et al, 2010a;Fagnani et al, 2014;Gabbi et al, 2016;Werncke et al, 2016).…”

Effect of dietary cation–anion difference on ruminal metabolism, total apparent digestibility, blood and renal acid–base regulation in lactating dairy cows

“…Blood pH changes may occur with high frequency in dairy cows, as blood acidification can occur resulting from DCAD reduction, ruminal acidosis (Ponce and Hernándes, 2005) or also high metabolic rate of lactating dairy cows (Fisher et al, 2012;Fagnani et al, 2014). Thus, based on results of the present study, increasing DCAD can maintain the blood pH near homeostasis, reduce milk concentrations of divalent cations, and probably contribute to avoiding problems with unstable milk proteins during ethanol test and also industrial heat treatment (Martins et al, 2015).…”

“…Therefore, lactating cows will have a high metabolic rate, experience more heat stress and be fed high non-fibrous carbohydrates feeds. All these factors may contribute to blood acidification and to increasing the incidence of metabolic diseases (Block, 1994;Fagnani et al, 2014).…”