Some effects of dietary crude fibre on live-weight gains and carcass conformation of pigs

Abstract

Pigs have a comparatively simple digestive tract with a limited alimentary capacity and are thus not adapted for utilizing appreciable quantities of bulky or fibrous foods; furthermore, they grow rapidly and are usually slaughtered when still actively gaining in weight. For these reasons fattening pigs are mainly given foods of good nutrient content, low in indigestible constituents. Although diets containing appreciable amounts of fibre, are known to cause a reduction in weight gains and efficiency of food conversion, they may nevertheless prove to be practicable when high-energy foods are costly, or scarce. In trials carried out from this point of view (Vestal, 1921;Lathrop & Bohstedt, 1938), it was found that the weight gains and food efficiency of self-fed weanling pigs were but little affected by dietary crude fibre provided the level did not exceed about 7 %.In an extensive series of trials carried out in Northern Ireland to study the effect of high levels of maize on back-fat quality, pigs were given diets containing from 30 % up to 60 % of maize meal and degermed maize meal; the respective levels of crude fibre ranged from about 5 % down to about 3£ %. In reviewing these trials Baskett (1939) noted that although the rates of live-weight increase and food conversion were all similar in the various treatments, a decrease in the fibre content of the rations was accompanied by poorer carcass grading, apparently due to increased back-fat thickness. Since the various levels of fibre were all fairly low, this result was rather surprising, and it was therefore decided to investigate further the apparent inverse relationship between dietary fibre and back-fat thickness by employing diets with a wider range of fibre contents, involving the addition of highly fibrous materials.

Effect of Feeding-Fasting Interval on Finishing Pigs: Weight Gain, Feed Utilization and Physical and Chemical Carcass Measurements

“…The weight of the empty stomach and intestinal tract was significantly increased with increased fasting interval (table 4). This increase is in agreement with other reports involving energy restriction by use of diets high in crude fiber (Coey and Robinson, 1954;Bohman, Hunter and McCormick, 1955;Merkel et al, 1958). The hyperphagia shown by intermittently starved rats (Holeckova and Fabry, 1959;Fabry et al, 1962) was associated with a marked hypertrophy of the gastric mucosa and musculature and increased weight of the empty gastrointestinal tract.…”

Some further observations upon the effects of varying the plane of feeding for pigs between weaning and bacon weight

“…There are, however, two negative values which suggest that low planes of feeding might decrease killing-out percentage. In both cases the reductions in plane of feeding were due partly to increases] in the crudefibre content of the diets, and these higher fibre contents, rather than the lower planes of feeding, might have been responsible for this inconsistency (Coey & Robinson, 1954).…”

Growth, economy of feed utilization and carcass quality in pigs in relation to dietary protein level and antibiotic administration

“…Comparisons with previously executed unpublished work strongly suggests that high energy/low fibre diets can lead to improvement in dressing percentage. This phenomenon is not altogether surprising in view of the corollary reported by Coey & Robinson (1954) and Manners (1956) who reduced the daily nutrient intake by qualitative variation in diets by increasing fibre levels. The fact that dressing percentage can vary within wide limits at bacon weights, points to the necessity for close scrutiny of feed conversion ratios which are commonly quoted on a live-weight basis.…”