Coordinated trials on the protein requirements of sows 2. A comparison of two levels of dietary protein in gestation and four in lactation

Abstract

ABSTRACT1. Gestation diets formulated to contain A, 9 or B, 11 % protein, and lactation diets with C, 13; D, 15; E, 17 and F, 19 % protein provided eight treatment combinations. They were given at 2 kg/day in gestation and approximately 5·7 kg/day in lactation to sows at eight centres, which remained on experiment for 3 to 5 parities and produced in total 529 litters. Mean results for parities 1 to 3 are given in this summary.2. Sows given more protein during gestation (i.e. diet A v. B) gained more weight in gestation (18·3 v. 22·5 kg net gain) but lost more in lactation (—1·7 v. —5·2 kg). Their offspring were significantly heavier at birth (1·31 v. 1·36 kg) and at 3 weeks old (5·28 v. 5·49 kg), but not at 6 weeks old (weaning).3. Giving more protein in lactation caused linear increases in piglet weights at 3 and 6 weeks, and a linear reduction in creep feed consumption. From a sample of sows whose milk yields were recorded, extra protein appeared to increase milk yield and its protein content. Extra protein for lactating sows also reduced their live-weight loss in lactation, but this effect was partially counterbalanced by smaller gains in gestation.4. No treatment had consistent significant effects on litter size or on the interval from weaning to conception. There were no significant interactions between gestation and lactation protein concentrations.5. The generally large differences between centres were in a few cases associated with centre × treatment interactions, but these were not such as to cast doubt on the general applicability of the main findings of the experiment.6. From this and an earlier experiment the minimum protein level for diets based on barley was concluded to be 11 % during gestation and 15% during lactation. For lactation diets, however, the economic optimum level may be > 15 %.

Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows

“…In rats and pigs protein deficiency during pregnancy has a negative effect on lactation performance only when the lactation diet is also insufficient in protein (Mahan & Mangan, 1975;Greenhalgh et al 1977;Shields et al 1985;Pine et al 1994). Thus, in modern feeding regimens the relatively-high-protein diets fed to cows during early lactation may mask the impact of moderate protein insufficiency of prepartum diets.…”

Threonine Requirement for Reproduction in Swine

“…The critical effects of amino acids fed during gestation on milk production and baby pig gain have been investigated in numerous experiments (Hoiden et al, 1968;Duee and Rerat, 1975;Frobish, 1978;Greenhalgh et al, 1980). A low protein gestation diet has been shown to precipitate a higher protein requirement during lactation (Mahan and Grifo, 1975).…”

The threonine requirement for reproduction in swine

“…One such problem is the unique affect on lactation performance of amino acid levels in the gestation diet. The critical effects of amino acids fed during gestation on milk production and baby pig gain have been investigated in numerous experiments (Hoiden et al, 1968;Duee and Rerat, 1975;Frobish, 1978;Greenhalgh et al, 1980). A low protein gestation diet has been shown to precipitate a higher protein requirement during lactation (Mahan and Grifo, 1975).…”