Uniformity in birth weight is heritable in Norwegian White Sheep
Sae-Lim, Panya ; Jakobsen, Jette H. ; Mulder, H.A. - \ 2018
In: Proceedings of the 11th World Congress on Genetics Applied to Livestock Production. - WCGALP - 6 p.
Sheep - Birth weight - Uniformity - Maternal genetic effect - DHGLM
Birth weight is an optimum trait where very high and very low birth weights are undesirable as they may cause issues, such as dystocia, stillbirths and diminished lamb vigor. Due to economic and welfare concerns, selection for more uniform birth weight is therefore desirable at all litter sizes. If uniformity in birth weight is heritable, selection against very high and very low birth weights can be conducted. The aim of the current study was to investigate if direct and maternal genetic variances in uniformity in birth weight exist in Norwegian White Sheep (NWS). Data composed birth weights of 136,992 NWS lambs born between 2000 and 2017 and corresponding sire-maternal grand sire pedigree. The double hierarchical generalized linear mixed model (DHGLM) was fitted. The direct and maternal heritability for uniformity of birth weight were 0.08 and 0.11, respectively, and larger than for many other uniformity traits in livestock. Furthermore, the direct (57.8%) and maternal (69.4%) genetic coefficients of variation for uniformity were substantial, revealing large potential for selection for more uniform birth weight in NWS lambs. Genetic correlations between direct and maternal genetic effects on birth weight and uniformity were 0.39 and 0.12, respectively, indicating that that selection for more uniform birth weight may reduce the average birth weight genetically.
Optimizing air flow distribution in maritime refrigerated containers
Lukasse, L.J.S. ; Staal, M.G. - \ 2018
In: 8th International Postharvest Symposium. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611900 - p. 1391 - 1398.
Cover - Gradient - Homogeneity - Reefer - T-bar - Temperature - Uniformity
Ever more intercontinental fruit transport takes place in reefer containers. The global installed fleet of 40 ft high cube reefer containers counts approximately 1,000,000 units. The reefer market has generally realized a compound annual growth (CAGR) of 5%. Product temperature requirements are very tight for highly temperature-sensitive fruit like grape and kiwi. Another application where temperature requirements are particularly tight is in cold treatment shipments, required as a quarantine measure by authorities of importing countries. In cold treatment shipments it is often hard to maintain the warmest product temperature below the regulatory imposed treatment limit, without causing chilling injury in the cold spots. Temperature gradients are reduced by good air flow distribution. T-bars make up the air ducts of reefer containers. Unfortunately most air escapes from the ducts before reaching the container door-end if no further measures are taken. An appropriate T-floor cover could help to guide more air to the locations where it is needed most. This paper reports on an experimental study with the aim to design an optimised T-floor cover and assess its effect on fruit temperature distribution. In a series of climate chamber tests it is investigated how temperature gradients are affected by four different T-bar cover designs. During the tests the container is stuffed with palletized empty cartons, with zero autonomous heat production. The results show clear positive effects of T-bar covers. The best of the four covers is non-perforated, of a trapezoidal-like shape, installed in the container with the narrowest end towards the door-end. It reduces the temperature difference between warmest and coldest measurement location by nearly 50%, and also accelerates temperature recovery after a power off period. In view of the promising results it is recommended to follow-up with real transport tests.
|Economic values of growth, feed intake, mortality, and uniformity for gilthead seabream (Sparus aurata)
Janssen, K.P.E. - \ 2016
Uniformity - gilthead sea bream - Sparus aurata