الكاتب: Multiple References

Two groups each of 10 suckler cows were given a basal diet of oat straw and pressed unmolassed sugar beet pulp for the last 19 weeks of pregnancy and the first 6 weeks of lactation . One group received 0 . 88 kg extracted soya bean meal (SBM) in pregnancy and 1 . 03 kg in lactation . The other was given 0 . 27 kg of a liquid supplement (LS) (containing inter alia urea and phosphoric acid) in pregnancy increasing to 0 . 33 kg in lactation . Both diets provided about the same amounts of digestible crude protein and about 10 g phosphorus (P) per day in pregnancy and 12 g P per day in lactation . Cows given SBM consumed marginally more straw but there were no differences in total diet digestibility . Cows given LS lost significantly more liveweight but their calves grew equally well . There were indications that cows given LS had slightly higher mean blood inorganic P and lower mean blood calcium (Ca) concentrations . Mean blood inorganic P concentrations were not below 1 . 4 mmol/l in pregnancy or 1 . 2 in lactation . There were no signs of reduction in voluntary straw intake or depraved appetite . When transferred to grass with a bull at the end of the experiment all cows were served within 24 days . It is concluded that these amounts of dietary P were adequate over the 25 weeks.