Coordinated trials on the protein requirements of sows 1. A comparison of four levels of dietary protein in gestation and two in lactation

Abstract

SUMMARY1. Gestation diets formulated to contain A, 9; B, 11; C, 13 or D, 15% protein, and lactation diets with C, 13 or E, 17% protein provided eight treatment combinations. They were given at seven centres at 2 kg/day in gestation and approximately 5·7 kg/day in lactation to sows which remained on experiment for three to five parities and produced in total 468 litters. Mean results for parities one to four are given in this summary.2. For gestation diets A to D mean litter size at birth was 9·7, 10·1, 10·3 and 10·4 live pigs, and at weaning (at 6 weeks), 8·2, 8·7, 8·8 and 8·8. Sows which received lactation diets C and E subsequently produced 10·4 and 10·3 pigs at birth and 8·9 and 8·3 at weaning.3. Gestation diets had no consistent effects on piglet weights. During lactation, however, diet E gave heavier pigs than C, by 0·2 kg at 3 weeks and 0·5 kg at weaning.4. Extra protein for either gestation or lactation had a positive effect on sow weight at that stage, but a negative effect in the following stage. There were no direct treatment effects on the time required for re-conception.5. Twenty experimental sows at the Rowett Institute, together with an additional group given diet A for both gestation and lactation, showed strong positive relationships between lactation protein intake and milk yield or composition.6. The treatment combination AC (i.e. 9% protein in gestation and 13% in lactation) gave the lowest weight of weaned pigs per litter, and CC gave the highest. The remaining treatments gave similar weights; of these BC (nominally 11 with 13, but actually 11·5 with 13·5% protein) was concluded to provide the lowest protein intake consistent with satisfactory performance.

Effect of Protein and Energy Intake by Primiparous Sows During Lactation on Sow and Litter Performance and Sow Serum Thyroxine and Urea Concentrations

“…The data of the present experiment agree with previously reported effects of energy restriction (Adam and Shearer, 1975;Reese et al, 1982a,b;Nelssen et al, 1985), and of protein restriction (Mahan and Mangan, 1975;Greenhalgh et al, 1977;NCR-42, 1978) during lactation on sow performance. King and Williams (1984b) found weight changes during lactation (average length 32 d) to be --35.8, -32.5, -29.8 and -3.9 kg for LE-LP, HE-LP, LE-HP and HE-HP treatments, respectively, whereas the corresponding sow weight changes in our experiment were -26.1, -18.0, -20.0 and -3.7 kg.…”

“…Furthermore, Mahan and Mangan (1975), Greenhalgh et al (1977) and NCR-42 (1978) have shown an increase in pig weight when a diet high in protein was fed to sows during lactation.…”

Valine Requirement for Reproduction in Swine

“…This response to low protein levels during pregnancy, and high protein levels during lactation has been reported by other researchers (Greenhalgh et , 1977 and1980;Mahan, 1977). In a later report Mahan (1981) agreed with the lowhigh sequence, but he also pointed out that due to the carry over re sponse from gestation to lactation, the lower protein level fed during gestation should correspond to a higher lactation protein level.…”

“…In a study (Greenhalgh et al^., 1977) involving 468 litters, four levels of protein were fed during pregnancy. It was found that 230 g of protein per day (or 11.5% of the diet) provided the lowest protein intake consistent with satisfactory performance.…”

Threonine Requirement for Reproduction in Swine

“…The primary measures of reproductive performance in sows include the number and weight of offspring weaned, sow weight loss and the intervals between litters (Greenhalgh et al, 1977). Apparently, amino acid requirements for fetal survival can be met almost entirely from the amino acids and nitrogen originating from the tissues of the sow .…”