The utilization of phytate-phosphorus by the transition dairy cow

Thumbnail Image
Lowry, Sarah
Major Professor
Committee Member
Journal Title
Journal ISSN
Volume Title
Research Projects
Organizational Units
Organizational Unit
Animal Science

The Department of Animal Science originally concerned itself with teaching the selection, breeding, feeding and care of livestock. Today it continues this study of the symbiotic relationship between animals and humans, with practical focuses on agribusiness, science, and animal management.

The Department of Animal Husbandry was established in 1898. The name of the department was changed to the Department of Animal Science in 1962. The Department of Poultry Science was merged into the department in 1971.

Historical Names

Journal Issue
Is Version Of

Phytate phosphorus (pP) availability in rumen fluid was analyzed during the transition period of two heifers by in vitro and in situ incubations. Apparent digestibility (AD) of P during the transition period was measured and P balance determined. The study included three periods, a prepartum period (P1), including the 2 wk prepartum, a postpartum period (P2), including a 4 wk postpartum and a post-transition period (P3) which corresponds to d 47 to 56 for cow 1854 and d 64 to 73 for cow 1847. In vitro [Subscript p]P availability of corn, soybean meal (SBM), whole cottonseed (WCS), a total of mixed ration (TMR) and phytic acid (PA) were determined. Percent [Subscript p]P loss was determined by in vitro incubation for 15, 30, 60, or 120 min following precipitation with ferric chloride. Percent [Subscript p]P loss, averaged across periods, was 90.78% in corn, 85.35% in SBM, 75.61% in WCS, 88.80% in TMR and 84.73% in PA. A significant period effect was observed for [Subscript p]P when PA was incubated, but not for corn, SBM, WCS, or TRM. In situ incubation of feeds and TMR showed that 99% of [Subscript p]P was either solubilized or phosphates were hydrolyzed after 72 h of incubation. Equations were developed to predict [Subscript p]P loss after a given incubation time. Apparent digestibility was determined in each period, using 24 h total fecal collection. Apparent digestibility of P was 56.03% in P1, 29.81% in P2 and 9.05% in P3. Period 1 was different than both P2 and P3. Phosphorus consumed (g/d), fecal P (%) and fecal DM (kg/d) were showed period effects. To determine P balance, TMR, intake data and fecal data from the AD study were utilized along with urine, milk, growth, and pregnancy P requirements. Urinary output was estimated and urinary P concentrations were determined. Phosphorus balance was -37.72 g/d in P1, 0.15 g/d in P2 and -24.09 in P3. Due to large standard deviations no difference was observed between periods for P balance. A cow effect occurred when urine P (mg/L and g/d) was analyzed. Results indicate that ruminants possess the ability to efficiently utilize [Subscript p]P.

Wed Jan 01 00:00:00 UTC 2003