Vergelijking van twee California Mastitis Testen met de elektronische celgetalbepaling voor de detectie van intramammaire infecties in mengmelkstalen van melkvee

In dairy cattle, the milk somatic cell count is the most widely accepted indicator for the presence of intramammary infections. The aim of this study was to compare the results of the electronic cell counting on 179 composite milk samples with the results of two commercially available California Mastitis Tests (CMT), based on either the thickening of the solution or the thickening of the solution in combination with a color change. The most frequently isolated major pathogens in the milk samples were Streptococcus uberis and Staphylococcus aureus and the minor pathogens most isolated were the non-aureus staphylococci. The somatic cell count estimated with the CMT-tests corresponded well with the one obtained with the Fossomatic (TM). For both CMT-tests, the test characteristics were mutually comparable as well as with the one obtained with the electronic cell counting. Based on the findings, it can be concluded that both CMT-tests can be used in the field to help detect cows suffering from an intramammary infection due to major pathogens

Het testen van een thermistorcryoscoop op de geschiktheid voor de bepaling van het vriespunt van Nederlandse koemelk

In 1986 zijn 2 typen van een nieuw vriespuntsbepalingsapparaat (thermistorcryoscoop) van het Duitse merk Funke Gerber op de markt. Voor het type CryoStar II automatic van dit merk is nagegaan of dit apparaat geschikt is voor de bepaling van het vriespunt van Nederlandse koemelk. Hierbij is gebruik gemaakt van monsters bestaande uit individuele koemelk en mengmelk

Coli-achtigen en E. coli in koe, melk en boerenkaas

Deze bacteriën zijn niet gewenst in boerenkaas, omdat ze o.a. smaakafwijkingen kunnen veroorzaken. E. coli kan bovendien ziekte veroorzaken

De invloed van erfelijkheid en milieu op de samenstelling van de melk bij Friese koeien en de praktische mogelijkheid van selectie op het eiwitgehalte

The milk composition of individual cows was studied especially as to protein content. In total 729 cows were tested including 238 dam-daughter pairs, 6 large progeny groups of bulls used in artificial insemination and 20 small progeny groups of bulls in natural service. Milk production, and fat, protein, casein, lactose and solids-not-fat were estimated during lactation.Environmental influences on milk production and composition were studied, e.g. lactation curve, month of calving, age of cow, duration of lactation. The average percentages fat and protein of individual cows were only slightly influenced and generally in the same direction by environmental factors.The variation in protein percentage (σ= 0.17) was smaller than that of fat (σ = 0.27) but this variation was still enough to permit successful selection on percentage protein.The protein percentage was positive correlated with fat content (r = +0.54). The percentage fat and protein were both largely determined by genetic factors (h 2= about 0.7). Taking account of the purpose for which milk was used, e.g. cheese production, especially protein was an economically important component of milk.Protein analysis on a large scale was cheap. For the Netherlands, and for Friesland in particular, it was definitely warranted to base payment for milk on percentages fat and protein and to select both on fat and protein