Nautakarjan kivennäisaineiden syönnistä laitumella. I

Authors

• Irja Uotila Maatalouden tutkimuskeskus, kotieläinhoidon tutkimuslaitos, Tikkurila

DOI: https://doi.org/10.23986/afsci.71452

Abstract

In this investigation the voluntary mineral matter consumption of milk cows and heifers on pasture has been studied. Two tests were performed with cows in the summer of 1957, their duration being 30 days (8. VI— 8. VII, test N:o I) and 75 days (10. VII—23. IX, test N:o II), respectively. The experimental animals were of Ayrshire breed. The mean live weight of the rows was 504 kg. The average number of cows was 36.5 in test N:o I and 35.1 in test N:o II, the corresponding milk yields being 11.4 and 8.9 kg per animal and day. Table 1 (p. 191) shows the distribution of the animals according to milk production class and Table 2 (p. 191) their distribution according to the time left before the next calving. The pasture grass was meadow fescue cocksfoot timothy-dominated and it had the following average mineral composition, calculated as dry matter: Ca 0.53 %, P 0.30 %, Mg 0.14 %, K 2.92 %, Na 0.07 %. The dry matter content was 20.0 % on an average. In test N:o I the cows were given Fodder salt mixture I (see p. 190) and common salt separately ad lib; on an average they consumed 35 g per day and animal of the former and 30 g per day and animal of the latter. Each animal thus obtained a daily quantity of 9.5 g Ca, 3.0 g P and 31 g NaCl (Table 3, p. 192). In test N:o II, Fodder salt mixture I, Fodder salt mixture II, Magnesia mixture, fodder bone meal and common salt were made available for the animals (see p. 190). The consumption of the three first mentioned mixtures per animal and day consumed was on the average, 10 g, 14 g and 10g respectively, (Table 4, p. 194), equalling in aggregate quantity the consumption of Fodder salt mixture I in test N:o I, which was then the only mixture administered. The animals ate fodder bone meal more willingly than the three first-mentioned mixtures consuming on an average 42 g per animal and day. In particular they readily accepted the fodder bone meal during the first 30-day test period, perhaps partly owing to some mineral deficiency or partly by virtue of its novelty. In regard to its manufacturing method, the bone meal was well suited for cattle feeding. In comparison with test N:o I, the cows ate the bone meal in test N:o II as an extra addition, for which reason the consumed Ca and P quantities were more than double in test N:o II (20.7 and 8.6 g per animal and day, respectively). The bone meal constituted a suitable mineral fodder in pasture feeding. The consumption of common salt was slightly higher in test N:o II than in test N:o I (38 and 31 g per animal and day, respectively). On an average the cows obtained 0.23 g magnesium per animal and day from the magnesia mixture and 0.31 g from the bone meal. (Also dolomite contains magnesium) No pasture tetany occurred in the cattle during the test, nor prior to the added Mg administration. The test with heifers had a duration of 40 days (22. VIII—1. X). during which time they were kept in the second growth of a clover meadow fescue cocksfoot timothy rotation ley. The number of animals was 12.3 on an average, their mean live weight at the commencement of the test 413 kg, their mean age 2 years, 1 month and 15 days, and the time left before calving 75 days on the average (one uncovered animal). They were offered Fodder salt mixture I, bone meal and common salt (Table 5, p. 195). The heifers ate hardly any Fodder salt mixture I (only 3 g per animal and day), whereas bone meal was accepted very willingly (78 g per animal and day). Common salt, too, was consumed abundantly (52 g per animal and day). The Ca quantity thus obtained was 23.2 g and the P quantity 10.8 g per animal and day. These quantities on an average exceed those consumed by the milk cows in either test. This may be attributable on one hand to the fact that the pasture fodder quantity consumed by the heifers is less than that of the adult animals (smaller size of the stomachs; lower food requirement), in consequence of which the quantities of minerals obtained with the fodder remain smaller, and on the other hand to the relatively high mineral requirement of growing heifers towards the end of pregnancy. Bone meal is suitable for use as mineral addition for heifers on pasture.