Original scientific paper
MILK FAT TO MILK PROTEIN RATIO AS AN INDICATOR OF NUTRITIONAL STATUS OF HOLSTEIN COWS ACCORDING TO VARIOUS STAGE AND LACTATION NUMBER
Sonja Jovanovac
; Poljoprivredni fakultet u Osijeku Sveučilšte J.J. Strosmayera u Osijeku, Hrvatska
Vesna Gantner
; Poljoprivredni fakultet u Osijeku Sveučilšte J.J. Strosmayera u Osijeku, Hrvatska
Nikola Raguž
; Poljoprivredni fakultet u Osijeku Sveučilšte J.J. Strosmayera u Osijeku, Hrvatska
Krešimir Kuterovac
; Agrokor d.o.o.,zagreb, Hrvatska
Drago Solić
; Hrvatski stočarski centar, Ilica 101, Zagreb, Hrvatska
Abstract
The data set consisted of 86,369 test day records of milk yield and milk composition of Holstein cows included in the AT milk control from January 2004 to October 2005. The Croatian Livestock Centre collected dana monthly. In all samples fat:protein ratio was about 1,25. Results of the analysis showed that 61.41% of milk samples were in the class with F/P ratio between 1.1 and 1.5, 11.45 % were in the class with F/P ratio > 1.5, while 27.14% of samples were in the class with F/P ratio < 1.1. The value of F/P ratio between 1.1 and 1.5 indicates appropriate crude fibre supply, while the ratio lower than 1.1, and higher than 1.5 indicates imbalance in the supply of crude fibre. The changes in frequencies of F/P ratio across the classes of nutritional status were not associated with lactation number, while the lactation stage affected the analysed variable. In most of the samples optimal F/P ratio (1.1 – 1.5) was determined during lactation. The proportion of optimal F/P ratio ranged from 54.74% in the first month of lactation to 64.44% in the tenth lactation month. The highest proportions of milk samples with F/P ratio > 1.5 registered in the early phase of lactation (first and second month of lactation) suggest a great energy deficiency. The percentage of milk samples with F/P ratio < 1.1 was slightly higher in later phases of standard lactation indicate disproportionate nutrition structure. It is obvious that monitoring milk fat to protein ratio leads to a possibility of correction of nutritional deficiencies in cows during lactation.
Keywords
Holstein cows; milk control; milk fat to milk protein ratio; lactation stage and lactation number; nutritional status
Hrčak ID:
26792
URI
Publication date:
4.9.2007.
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