Influence of Strain and Sex on the Relationship of Protein to Energy in the Rations of Growing and Finishing Bacon Pigs

Abstract

Rations varying in energy (65 to 79 per cent TDN or 69 to 88 per cent apparent digestible energy) and protein (13 to 21 per cent) were studied in two experiments with 120 pigs of four strains. Rate of liveweight gain tended to be fastest in pigs fed high energy-high protein rations throughout. Males gained more rapidly than females, with strain differences being evident. Strain × sex interactions in rate of gain were present in both the growing and finishing period, with a ration × strain interaction present in the growing period. There was an indication that in the growing period pigs on high energy, particularly high energy-high protein rations ate more than pigs fed low energy rations. In the finishing period low energy rations were consumed at a higher rate than high energy rations with protein level having no influence on feed intake. In the growing period to 110 pounds, high protein rations resulted in improved feed efficiency as compared to medium protein rations, while in the finishing period to market weight high energy rations were more efficient than low energy rations. There was evidence that high protein alone or in combination with high energy rations also improved efficiency of feed utilization in the finishing period. Female pigs required less feed per pound gain than male pigs in the finishing period. High energy rations resulted in increased dressing percentage and generally inferior carcasses. There was an indication that high protein rations resulted in leaner carcasses. Carcass length was not influenced by ration. Carcasses from female pigs excelled those from male pigs in all factors measured except carcass length. Strain differences in carcass characteristics existed but no appreciable strain × ration interactions were noted.

Tissue Development in Swine as Influenced by Liveweight, Breed, Sex and Ration

“…However, there was still a need for an anatomical study in swine which would encompass not only normal patterns of tissue growth but also the direct influence of outside factors on these patterns. CANADTAN Cuthbertson and Pomeroy (1.962) in swine, Berg (1968) and Berg and Butterfield (1968) (Bowland and Berg, 1959;Braude et al, 1963;Brooks et al, L964;Buck, 1963;Cuthbertson and Pomeroy,1962;McCampbell and Baird, 1961; Wagnet et aI., (1963). By 91 kg liveweight, pigs had 84Vo of-the muscle and 66Vo of the fat that was present at 1'I4 kg liveweight.…”

Effects of Dietary Protein Level and Sex on Swine Performance and Carcass Traits

“…Many studies have shown that an increase in lean content of pork carcasses has been achieved by feeding higher levels of prorein (1,2,6,'g, 10). Consequently, some suppliers of swine feeds have' recommended a'single highprotein rltiol to be fed through growing and finishing srages.…”

“…The objectives of this study were to evaluate the efiect of levels of dietary protein and sex on performance and carcass traits, and possible g.notyp'" (99x) b1r environmeni (level of protein) interaction (2) found that gilts required less feed per pound of gain, but had a smaller average daily gain than bairows during the finishing period; this apparent contradiction, compared with our findiigs, in growtt and feed efficiency may be partially explained bv the strain by sex interaction observed in their experiment but not in ours.…”

Abstracts of Communications

“…Some of these are inherent problems common to all species and some refer to the methods of experimentation and the parameters used to measure efficiency in the pig. In the first category are factors such as the changing requirements during growth (Braude, 1958) the effect of genotype (Bowland & Berg, 1959) the endocrine status of the animal (Prescott, 1963) and the sex (Robinson & Lewis, 1964) as well as considerations such as the non-availability of amino acids. Problems associated with the method of experimentation have only recently been recognized.…”