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Title: Electronic feeders in the genetic improvement of pigs for the efficiency of lean growth
Author: Hall, Anthony Douglas
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1997
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Many pig breeding companies now test their young pigs on electronic feeders. This provides them with the means of obtaining accurate estimates of individual feed intake in a group housing system, which is similar to the production environment. Electronic feeders also provide new information on the pattern of how this feed was consumed, such as number of meals in a day or the size of each meal. The aims of this thesis were: to describe these feeding pattern traits in an objective manner; to determine any major environmental or social effects on them; to estimate genetic and phenotypic parameters for them; to predict their potential benefit for increasing the accuracy of selection for land growth and feed efficiency. The data used in these analyses were compiled between 1992 and 1995 from individual records of 1832 pigs from 70 sire families of a Large White derived sire line selected for lean tissue growth rate. Pigs were fed ad libitum, in single sex pens of 12 pigs (s.d. 0.87), using FIRE (feed intake recording equipment) system from Hunday Electronics Ltd. at the Cotswold Pig Development Company. Pigs were on test between 45 kg (s.d. 2.76) and 95 kg (s.d. 6.78). Daily feed intake (DFI kg), feed intake per visit (FIV kg), number of visits per day (NV), duration of each visit (TV mins.), time in the feeder day (TD mins.), feeding rate (FR kg/min) and number of non-feeding visits per day (NFV), were measured as means of test and also as means of bi-weekly periods of test (which were the means of weeks 2-3, weeks 4-5, weeks 6-7 and weeks 8-9). Feeding patterns were affected by the social and physical environment within a pen, particularly time spent in the feeder per visit and per day. DFI and performance test traits were unaffected which suggests that pigs were able to adapt their behaviour to compensate for different social structures within a pen. Genetic and phenotypic parameters were estimated by restricted maximum likelihood with a multivariate individual animal model. DFI had a heritability of 0.21 ranging from 0.18 to 0.26 over the four bi-weekly test periods. Correlations between part and whole test records of feeding patterns and DFI were high (rg = 0.75 to 0.99). DFI was highly correlated with performance test traits, but had low correlations with feeding pattern traits. The heritabilities of feeding pattern traits were low except for FIV and NV, but correlations between feeding pattern traits were high. FIV, NV and TV were moderately correlated with performance test traits.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available