Steven Janssens

Genetic parameters for intramuscular fatty acid composition and metabolism in pigs.

The aim of this study was to estimate genetic parameters for pork intramuscular fatty acid (FA) composition and indices for desaturase and elongase activities involved in n-3 and n-6 PUFA metabolism. The LM of 437 slaughter pigs was analyzed for FA composition (expressed as g/100 g of FA). Indices for enzyme activities were calculated from product to precursor FA ratios. Genetic parameters were estimated with single- and multi-trait animal models. The total FA content, reflecting the intramuscular fat content, was either included or not in the model. Results from the models without total FA content showed relatively high heritability estimates, generally above 0.50, for the proportion of the most important MUFA and PUFA, compared with much smaller values for the SFA. When total FA content was included in the models, heritability values decreased (P < 0.001) for most individual FA and for all sums of FA groups, except for C18:0, C18:3n-6, and C18:3n-3. Heritability estimates for the ratios C20:4n-6/C18:2n-6 and C22:6n-3/C18:3n-3, reflecting the overall conversion in the n-6 and n-3 PUFA pathway, respectively, were 0.29 and 0.35, respectively, with total FA content in the model and increased to 0.38 and 0.49, respectively, if total FA content was not in the model. Heritabilities for other more specific indices were of the same order. Genetic correlations between PUFA proportions and indices for enzyme activities with ADG were mostly negative, whereas the correlations with carcass lean meat percentage were mostly positive. It was concluded that there is meaningful genetic variation for long-chain PUFA metabolism that is only partly dependent on the carcass and muscle fat content. This may allow selection for improved FA composition of pork.

A data-acquisition system for electronic identification, monitoring and control of group-housed pigs

This paper describes a data-acquisition system which has been developed to measure, in parallel, individual body weight and feed intake of growing pigs kept within a group, their body temperature and physical activity. This multitude of signals originating from physiological and behavioural parameters can be collected in relation to environmental parameters on a continuous and long-term basis. A modular distributed multiprocessor architecture was developed to allow easy post-processing of collected data and to guarantee a flexible integration of data into a more extended data management system. A periodical and complete automatic transfer of locally stored data to a central computer unit has been implemented. Communication protocols are standardized allowing data transfer to and from other networks. The availability of an electronic identification system combined with various sensors will provide opportunities to study possible improvements of handling, housing and transport of farm animals.

Changes of body temperatures of piglets as related to halothane sensitivity and treadmill exercise

Abstract 1. 1. Subcutaneous temperatures of homozygous halothane positive, homozygous halothane negative and heterozygous piglets were measured at five different body spots [abdomen, ear (left, right), neck (left, right)] under individual housing conditions and during a treadmill exercise. 2. 2. Statistically significant differences were observed in the levels, patterns and dynamics of subcutaneous temperature of the different genotypes, both at rest and during exercise. During the night subcutaneous temperatures were lowest for the positive homozygotes, but highest in this group after treadmill exercise. Subcutaneous temperatures of heterozygotes were equal to those of negative homozygotes during the night, but after exercise was equal to that of positive homozygotes. 3. 3. In the heterozygotes bucutaneous temperatures on the abdomen were higher than those of the base of the ears, with these being higher than those of the neck region.

Electronic Identification and Physiological Monitoring: Data Collection Efficiency and Powering Requirements

When measuring pigs’ body temperature subcutaneously with a telemetric device during housing and handling, data collection efficiency was 80% and 30%, respectively. With this over-all performance respective 4 and 10 readings/transmissions are necessary to collect at least three physiologically relevant data for calculating a mean value per reading/transmission. For active transponders, the sampling frequency will therefore determine the life time of the available battery.