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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Mineral Status Survey and Mineral Supplementation Trial with Breeding Beef Cattle in Calintaan, Occidental Mindoro

(Philippines), Doctor of Philosophy in Animal Science (University of the Philippines Los Baños)

Dissertation Abstract:

Three ranches in Occidental Mindoro (southwest of Luzon island, Philippines) were assessed to determine existing mineral deficiencies or toxicities and the most susceptible classes of cattle with protein and energy were studied in one of these ranches.

Phosphorus (P) and manganese (Mn) were deficient in all the soils. they were borderline to deficient in potassium (K) and copper (Cu). Of the 75 grasses analyzed, 72, 17.3, 72, and 49 percent were deficient in P, K, sodium (Na), and zinc (Zn), respectively. Sporobulus indicus and Paspalidium flavidum contained toxic levels of Mn (150 ppm). For legumes, 70.7, 62.5, and 12.5 percent were deficient in P, Na, and Zn, respectively. Desmodium lasiocarpum and D. styracifolium contained possible toxic levels of Mn. For shrubs and broad leaf plants, 24.4 percent were deficient in P and 58.8 percent in Na. Toxic levels of Mn were present in Bridelia stipularis, Triumfetta bartramia, and S. acuta. A toxic level of iron (Fe) was found in Sida acuta.

All three cattle classes and ranches appeared to be deficient in serum Cu. Dry cows in all ranches were borderline to deficient in P. Lactating cows were deficient in both P and magnesium (Mg).

Except for the November sampling and the salt-supplementated group, all had the prescribed adequate Ca level. Mineral supplementations apparently decreased serum Ca. Serum P was higher (P<0.07) among P-supplemented cows and also during dry season (P<0.07). The levels were lower than normal except for the July sampling. Serum Mg levels were highest (P<0.01) during wet season and lowest during dry season. Sera Cu and Fe were not influenced by mineral supplementation. But Cu, which differed (P<0.05) between age groups and period of collection (P<0.01), was highest during rainy season. However, both sera Cu and Fe decreased during dry season. All other levels were deficient except serum Cu during wet season.

Mineral supplementation did not affect liver concentration, although animals receiving salt tended to have lower levels of Cu, Zn, and Fe. Liver Cu at initial biopsy was deficient; all others were in the low normal range.

Younger cows apparently responded better to mineral supplementations. with pregnancy rates of 57.14, 71.43, and 42.86 percent for Complete Mineral Mixture (CM); CM + energy + nitrogen (CMEN); phosphorus; and salt, respectively, versus 27.39 percent initial pregnancy rate. These results, however, were merely indicative due to lack of experimental animals.

Mineral supplementation had little effect on pregnancy rate of older cows. Nonetheless, older cows generally had significantly higher (P<0.06) pregnancy rate.