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67. Survey on smallholder dairy farms in the Mid-Country, Sri Lanka

Author

De Bont, J., Van Aken, D., and Vercruysse, J.

Subjects
Calf, lcsh:Agriculture, Husbandry, lcsh:S, Sri Lanka
Abstract

On smallholder dairy farms (average 2.7 cows) 40 cows and their calves were followed over a period of one year. Calving interval was 453 days, interval calving to first heat was 106 days and calving to conception 175 days. The number of services or inseminations per conception was 1, 6 ; natural service was more successful than artificial insemination. Inefficient oestrus detection was the major cause for poor reproductive performance. Average milk production up to six months postpartum was 1225 litres with a peak yield of 8.2 litres. Quantifies of concentrate fed (2.5kg/day) were not related to the yield and remained constant. Average birth weight was 27 kg ; daily growth rate up to six months was 272 g. Mortality up to six and twelve months was 18 and 40 % respectively. Deficient colostrum feeding and omphalitis were common. Gastrointestinal nematodosis and coccidiosis were present but levels of infection and absence of clinical signs did not justify blind treatments. It is suggested that although husbandry and veterinary problems exist, economie factors like low milk price and high cost of inputs are the major causes for stagnancy in the smallholder dairy sector in this area.

Published
1990

68. Calculations of the motions of a ship moored with Moormaster units

Author

de Bont, J. (author), van der Molen, W. (WvdMolen@csir.co.za) (author), van der Lem, J. (C.vanderlem@Royalhaskoning.com) (author), Ligteringen, H. (H.Ligteringen@tudelft.nl) (author), Mühlenstein, D (dm@dhi.dk) (author), Howle, M. (Mike.Howle@cavotec.com) (author), de Bont, J. (author), van der Molen, W. (WvdMolen@csir.co.za) (author), van der Lem, J. (C.vanderlem@Royalhaskoning.com) (author), Ligteringen, H. (H.Ligteringen@tudelft.nl) (author), Mühlenstein, D (dm@dhi.dk) (author), and Howle, M. (Mike.Howle@cavotec.com) (author)

Abstract

Container ships should only make very small horizontal movements at the berth for efficient (off loading of containers. This is especially a concern in ports directly facing the open ocean, where high swells at sea can cause harbour oscillations and low-frequency surge motions of the ship. Cavotec MSL has developed a new mooring unit, the MoorMaster™, which replaces conventional mooring lines. The hydraulics of the system have a strong reducing effect on the motions of the moored ship. Measurements at a container terminal have shown that the surge motion of container ships was reduced from an amplitude in the order of 1 metre to an amplitude in the order of 5 centimetres, by using MoorMaster™ units. However, before MoorMaster™ units can be installed with confidence in other (new) terminals and comparisons can be made with other mooring systems, the characteristics of MoorMaster™ units should be included in numerical models for motions of moored ships. This paper compares the results of numerical simulations and measurements for motions of ships moored with MoorMaster™ units. The comparison shows that the effect of the MoorMaster™ units on the ship motions is taken into account well by the numerical model. However the exact magnitude and frequencies of the motions of the moored ships differs for measurements and simulations, mainly because of several unknown parameters during the measurements.

Published
2010

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