The quantitative effects of feed restriction in fattening pigs on weight gain, efficiency of feed utilisation and backfat thickness

Abstract

From the published data summarised in Table 1, it was calculated that, at an average degree of feed restriction of 15·8 %, daily weight gain decreased by 12·50% (or 0·78% for each 1% restriction), feed conversion efficiency improved by 3·96% (or 0·31% for each 1% restriction) and backfat thickness diminished by 7·63% (or 0·53% for each 1% restriction).Equations were calculated to show the degree to which daily weight gain, feed conversion efficiency and backfat thickness change with increasing feed restriction (Figures 1, 2 and 3).As the degree of feed restriction increases, the decrease in daily weight gain becomes relatively greater and the decrease in backfat thickness relatively smaller. Efficiency of feed utilisation, however, improves at first, but eventually decreases as restriction becomes more severe.It is thought that the equations found can be used, within certain limits, to calculate the average effects of feed restriction for different breeds of pigs, which when fed ad libitum consume 2·7 kg. meal ration (of normal composition) per day and have a growth rate of about 750 g. daily from 30 to 90 kg., and backfat thickness of about 37 mm. when kept under average environmental conditions.

Effect of average daily food intake on production performance in growing pigs

“…This is misleading, however, because parameter estimates were inaccurate, as reflected by high residual s.d.s. The effect of FI on FCR in the present experiment was less than in the work of Vanschoubroek et al (1967), who found a proportional difference of more than 0-06 between FCR at ad libitum FI and at 0-75 of ad libitum, but in line with newer concepts of growth and food intake. Recently, however, Campbell et al (1985) found rather strong relations between FCR and energy intake with a minimum FCR at 33 MJ DE per day.…”

“…The response of backfat thickness (BF) to i n increasing FI appears to be not significantly different from linearity (Vanschoubroek et al, 1967;Fuller, 1971;ARC, 1981). The relation between FI and protein retention or lean tissue growth rate (LTGR) is not clear.…”

“…minimum at proportionately about 0-75 of ad libitum intake (Vanschoubroek et a/., 1967; RELATIONS between average daily food intake Davies and Lucas, 1972). Results of Fuller (FI), either ad libitum or restricted, and (1971) indicated that FCR was only slightly production traits in growing pigs have been influenced by FI in the range of 1-6 to the subject of many studies.…”

“…However, Campbell, however, are less consistent. Reviews by Taverner and Curie (1985) found curvilinear Vanschoubroek, Wilde and Lampo (1967) and relationships between DG and FI and Fuller (1971) showed a diminishing return between FCR and FI in 24 entire males and response of daily live-weight gain (DG) to 24 females growing from 48 to 90 kg live increasing FI, whereas the Agricultural weight. Minimum FCR was at 33 MJ Research Council (ARC, 1981) concluded the digestible energy (DE) intake per day, being response was linear.…”

The Effect of Fiber Addition to Diets Formulated to Contain Different Levels of Energy and Protein on Growth and Carcass Quality of Swine

“…Cunningham et al (1962) concluded that the period of adaptation has little influence on the pig's ability to digest cellulose. However, Friend et al (1962) (Lucas and Calder 1956;Troelsen and Bell 1962;Vanschoubroek et al 1967) or where changes in palatability arise from excessive levels of, or inhibitory substances (Hanson et al 1956) For personal use only.…”