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Calcium and Phosphorus Requirements of Growing Philippine Indigenous Sheep
Dissertation Abstract:
A 16-week feeding trial in a 3 x 2 factorial experiment involving three levels of calcium (Ca) and phosphorus (P) in the different rations (A= 2.6 g Ca and 1.17 g P/kg dry matter (OM); B = 3.85 g Ca and 1.76 g P/kg OM; and C = 5.06 g Ca and 2.3 g P/kg OM) and two sexes (male and female) in a randomized complete block design was conducted. Nine male and nine female growing sheep (8-18 kg) were used to determine the required level of Ca and P, and the effect of supplementation on the Ca and P status and production performance on the development of the sheep's reproductive system and metabolism.
Lambs fed with ration 8 had significantly higher OM intake and liveweight (LW) gain. These animals consumed significantly more Ca but this did not affect the serum Ca concentration. Serum Ca was significantly affected by collection period and the interaction of sex and collection period wherein the concentration decreased over time in males but increased in females. The mean serum P concentration decreased with time in lambs fed with ration A and was lower in the females. Serum P was increased over time in lambs fed with rations B and C but to a higher extent in the males fed with ration B and females fed with ration C.
Calcium and P were mainly excreted through the feces and only minimally in the urine. Fecal Ca and P as well as apparent absorption and retention of Ca and P were highly and positively correlated to intake. Calcium and P balance was negative in the lambs fed with ration A while those fed with rations Band C were in positive balance except for a slightly negative Ca balance among ewe lambs fed with ration B.
No significant differences in the Ca and P concentration in the rib bones were detected except for a significant (P<0.05) ration x sex interaction effect on P concentration in the rib taken after 16 weeks of feeding. The females fed with ration A had slightly reduced Pin the ribs at the end of the study.
The pH levels of the digesta of each compartment of the gastrointestinal tract were not significantly different and were within normal levels. Ca concentration in the rumen-reticulum, omasum, and cecum and P concentration in the omasum were significantly higher in animals fed with rations B and C.
Wool growth was significantly faster in lambs fed with ration B. Mean measurements of male and female reproductive parameters did not differ among rations but animals fed with ration 8 tended to have higher values. Histological examination of the seminiferous tubules showed the presence of more layers of cells in the germinal epithelium of animals fed with ration B.
Based on these results, it appeared that a 15-kg growing male Philippine indigenous sheep should consume 131.0 mg Ca/kg LW/day and 57.0 mg Plkg LW/day of ration 8 , while the females should consume 167.6 mg Ca/kg L W /day and 82.8 mg P/kg L W /day of ration C.