Effect of source and concentration of supplemental trace minerals on apparent absorption and retention, performance and physiological indicators of trace mineral status in lactating Holstein dairy cows

• Author / Creator

  Briggs, Nicole T

• Inorganic sources of trace minerals are commonly supplemented in dairy cow diets; however, there has been an increase in the supplementation of minerals complexed with organic compounds. Organic sources of trace minerals are thought to be protected from antagonistic interactions within the gastrointestinal tract and therefore have increased bioavailability for absorption and rumen fermentation, enhancing their utility for production. The objective of this study was to investigate the effect of source and concentration of supplemental trace minerals on productivity, apparent absorption, apparent retention, rumen fermentation parameters and physiological indicators of trace mineral status (vitamin B12 and glutathione peroxidase) in lactating Holstein dairy cows. Six lactating, cannulated, Holstein cows (129 ± 12 DIM; mid to late lactation) were used in a 6 x 6 Latin square design with a 28-d of experimental period (23-d of adaptation and 5-d of sample and data collection). The same basal diet was fed daily, but with different sources (organic [ORG] versus inorganic [INO]) and concentrations (50%, 100%, and 200% based on NRC recommendations) of supplemented trace minerals (Co, Cu, Mn, Se, and Zn). During the 5-d data and sample collection period, feed intake, water intake, blood, total milk, urine, and feces were collected daily, while rumen fluid and pH were collected during the final two days of the sample collection period. Results from chapter 2 revealed organic trace mineral supplementation decreased milk yield and milk fat yield compared to inorganic supplementation; however, low levels of organic trace mineral supplementation resulted in the same milk yield as all levels of inorganic supplementation. Fecal excretion of all trace minerals increased with increasing concentration of trace minerals in the diet. Organic cobalt supplementation exhibited higher apparent absorption and retention which could be an indication of organic cobalt having increased bioavailability. Selenium apparent absorption and retention were impacted by dietary mineral concentration, where high levels of organic and inorganic supplementation showed higher absorption and retention than low levels. The results in chapter 3 showed that source and concentration of supplemental trace minerals did not impact serum trace mineral status with the exception of cobalt at high levels (200%) of supplementation and did not impact serum GSH-Px activity or the concentration of vitamin B12 concentration in plasma, ruminal fluid or milk. Organic trace mineral supplementation decreased the minimum rumen pH compared to inorganic supplementation. In addition, treatments affected the rumen environment in a dose-dependent manner where high organic supplementation (200%) was not beneficial in the production of total VFA compared to low (50%) organic supplementation and source and concentration of trace minerals caused a shift in the proportions of certain major and minor VFA excluding butyrate and valerate. Low organic could replace inorganic trace mineral supplementation without observing changes in productivity. As production results in low organic and inorganic supplementation are similar, more efficient supplementation of trace minerals to lactating dairy cows would allow producers to be more sustainable (reduce excretion and environmental impact) and profitable (reduce feed costs), while still maintaining performance of the herd.

• Subjects / Keywords

  • Nutrition
  • Performance
  • Holstein
  • Trace Mineral
  • Dairy
  • Absorption

• Graduation date

  Spring 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-24kc-4t16

• License

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