The aim of this study was to determine the effects of fatty acids and triglycerides composition on melting behavior of milk fat. The melting profiles, fatty acids composition and triglycerides composition of milk fat from 27 cows fed palm oil, rapeseed oil and a low fat diet were analyzed. Correlations between individual fatty acids and triglycerides, and the melting off-set temperatures of milk fat fractions were obtained using multivariate data analysis. Low fat feeding increased the proportion of short and medium chain fatty acids and decreased the proportion of long chain fatty acids. The opposite effect was observed in milk fat of cows from lipid supplemented diets. Palmitic and myristic acids correlated positively to the melting off-set temperatures of high melting fraction of milk fat while oleic and linoleic acid had strong negative correlations. Furthermore, high molecular weight triglycerides contributed positively to the melting off-set temperatures of high melting fraction of milk fat. This is the first study to demonstrate that the melting off-set temperatures of high melting fraction of milk fat can be affected, to some extent, by dietary manipulations of cows. However, melting off-set temperatures of milk fat were still under physiological temperatures of cows indicating that the biological mechanism secure full milk fluidity under most dietary manipulations. Knowledge from this study could help to characterize melting fractions of milk fat resulting from different feeding regimes. This could aid in milk fat fractionation for use in specialty ingredients or modification of functionality of milk fat (e.g. softness or spreadability) in fat-based products.
Udder quarters suffering from chronic and therapy-resistant infections represent a serious problem for dairy farms. Drying off such udder quarters during lactation would offer an opportunity to remove these single quarters from milk production without losing the whole milk yield of one cow during the current lactation. The use of a casein hydrolysate (CNH), an enzymatic fission product of casein, hence an endogenous substance, showed promising results regarding downregulation of milk secretion in udder quarters of high yielding dairy cattle in previous investigations in Israel. The objective of this study was to prove whether the infusion of CNH into the bovine mammary gland is an appropriate method to downregulate milk secretion in chronically infected udder quarters in high yielding dairy cows in Germany in order to dry off these single quarters without inducing clinical mastitis. Each treated udder quarter received six intracisternal infusions of CNH within 3 treatment days. After the last infusion of CNH on day 3, milking of the affected udder quarter was stopped. In 21 out of 24 (87.5 %) quarters a successful drying off could be achieved and only three quarters showed clinical mastitis. Furthermore, none of the animals showed a defence response or signs of pain during the intracisternal application. An increase in the average somatic cell score (SCS) during the treatment period could be revealed and 11 out of 16 conventionally milked quarters showed a decrease in milk yield. Hence, it could be shown that the infusion of CNH is an effective and gentle method for downregulating milk yield and drying off chronically infected and therapy-resistant single udder quarters during lactation.
Bovine mastitis is commonly treated with antibiotics, which does not always succeed and therefore, sometimes is unnecessary. Bacteriological cure is the goal of antibiotic therapy and depends on the causing microorganism, the applied therapy, and on animal-related factors. Determining the animal-related part of the probability of bacteriological cure before applying antibiotics might help to reduce unnecessary usage. By now, this is only possible by considering individual cow data including animal-related factors such as age, mastitis history and somatic cell count. Former studies revealed that chronic mastitis lowers the probability of cure and leads to specific characteristics found in the differential cell count. The aim of this study was to develop a flow cytometric cell differentiation tool to determine animal-related factors correlating with a score-based probability of bacteriological cure. Therefore, the proportions of different cell types and their vitality in 874 Dairy Herd Improvement milk samples of 239 cows were determined by flow cytometry. The results were tested for a correlation between data of flow cytometry and the calculated animal-related probability of bacteriological cure of each individual cow by binomial logistic regression analysis. A statistically significant association to the calculated and animal-related probability of bacteriological cure could be shown for highly granulated cells, non-vital cells and macrophages. With this model, 84.4 % of all animals could be allocated to their estimated animal-related probability of bacteriological cure correctly. These findings suggest that flow cytometric cell differentiation might become an innovative tool to estimate animal-related prognosis for bacteriological cure.
The compositional and physical parameters of alcohol positive milk (APM) of different buffalo breed were studied and compared with their average of total milk samples for one year. Total 966 milk samples were collected from four buffalo breeds, Murrah, Nili-Ravi, MurrahxChinese local buffalo (Mu-Ch) and MurrahxNili-RavixChinese buffalo (Mu-Ni-Ch) and were analyzed for alcohol stability at 64%, 66%, 68% and 70% (v/v) of alcohol. Results of milk compositional and physical parameters differ significantly (P <0.001) among the breeds. The APM rates of Mu-Ch and Mu-Ni-Ch were higher than Murrah and Nili-Ravi. The APM had higher acidity, milk protein and non-fat solids (NFS) and lower freezing point than average of total milk samples. When comparing different buffalo breeds the APM rates seemed mainly positive related to acidity and no special relationships with other parameters. In conclusion, a fixed alcohol level was not suitable for milk from different buffalo breeds for the alcohol test. Milk with higher acidity, protein, NFS and lower freezing point has higher sensitivity to alcohol in different buffalo breeds, and alcohol stability showed mainly a positive relation to milk acidity.
