An experiment was conducted to analyze feed, climate and animal factors affecting dry matter intake (DMI) in lactating dairy cows. Sixteen lactating Holstein cows, with parity from 1 to 6, were assigned to a feeding trial for 2 years, comprising 31 lactations. The animals were fed Italian ryegrass silage, oat hay, alfalfa hay, beet pulp and three types of concentrate. The data, pooled and classified by stage of lactation, season of lactation and parity were analyzed by stepwise multiple regression to determine the nature and extent of factors affecting DMI. A total of 45 prediction equations for DMI were derived. Energy-corrected milk yield or milk yield was selected as the primary factor of DMI in all the equations in which the ratio of contribution (R 2 ) varied from 0.26 to 0.67. The dietary concentration of organic cell wall, crude fiber, crude protein, organic b fraction, forage to concentrate ratio, average ambient temperature and temperature-humidity index were selected as the secondary factors affecting DMI for pooled data, late lactation (251-350 days of lactation), summer (June-August), spring (March-May), ≥4th lactation, autumn (September-November) and 3rd lactation, respectively, and improved R 2 up to 0.77. Except for an impact of bodyweight in several equations, feed and climatic factors significantly improved prediction equations effectively for data classified in different ways. To estimate DMI accurately in lactating dairy cows, feed and climatic factors should be considered for specific conditions.

Diversity of chemical composition, in vivo digestibility and in situ dry matter degradability of oat hay (Avena sativa) were studied. Oat hay samples obtained from 22 batches imported were analyzed for chemical composition. The result showed a wide range of variations in crude protein (3.9–8.8%, on a dry matter basis), crude fiber (22.1–35.2%), nitrogen free extract (50.0–66.0%), organic cellular contents (23.4–40.0%), organic cell wall (53.1–70.8%), organic a (4.1–9.8%), organic b (49.0–63.8%) fractions and the estimated total digestible nutrients (50.3–63.8%) from the organic components. Of these, four oat hay samples were used for the measurement of dry matter intake, in vivo digestibility and in situ dry matter degradability in sheep. Significant differences were observed for the dry matter intake, in vivo digestibility of dry matter, crude protein, crude fiber and nitrogen free extract, dry matter disappearance at 48 h and effective degradability at k = 0.05 h−1 of the samples (P < 0.05). The results revealed a wide range of diversity of nutritional quality of the imported oat hay that could have an affect on production potential in animals.

This paper concerned with the numerical study of thermal and mass diffusive natural convection flow inside a triangular shape solar collector using finite element method for the governing equations expressing the velocity pressure formulation along with the energy and concentration balance equations. In the solution procedure, the isothermal and isoconcentration boundary conditions are assumed at the absorber and covers of collector. Local and mean heat and mass transfer rates for the thermal Rayleigh number and Lewis number are presented. Streamlines, isotherms and isoconcentration are also presented for the aforesaid parameters. The result found in this study fully agreed with the previous published work. But this result will be profitable for the design of the collector.