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J F Greenhalgh

Publications and source records attributed to J F Greenhalgh.

14 recordsLinked to original sources
PubMed1981

Effects of feeding level in late pregnancy and dietary protein concentration during early lactation on food intake, milk yield, liveweight change and nitrogen balance of cows.

Thirty-nine British Friesian cows and 17 British Friesian heifers were used to measure the effects on milk yield, food intake and digestion, and N balance of increasing the protein concentration in the diet from 111 to 147 g crude protein/kg day matter during the first 16 weeks of lactation. The comparison was made for animals given food either ad lib. or at a level which allowed them to gain 0.5 kg/d during the 8 weeks before parturition, and for animals given ad lib. diets of either 60:40 or 40:60 hay:concentrate ratio during early lactation. Milk yield was increased by a higher protein concentration in the diet (P less than 0.01) and the increase was evident from the first week of lactation. Mean increases over the first 8 weeks of lactation were 3 kg/d for animals on the diet of high roughage content and 7 kg/d for animals on the diet of low roughage content. A higher crude protein content in the diet also increased food intake (P less than 0.05) and digestion (P less than 0.05), and the increases were greater for animals given the diet of low compared with high roughage content. Level of feeding before parturition did not influence food intake or milk yield and there were no differences between cows and heifers in their response to treatments. N balance over the first 10 weeks of lactation averaged -13 g/d for cows and 6 g/d for heifers (P less than 0.025), and was not significantly altered by treatments. Mean N balance of all animals was estimated to increase from -37 g/d immediately after parturition to zero at 8 weeks of lactation. The results demonstrate that an increased protein concentration in the diet during early lactation is associated with increased food intake and digestibility of food, which are in the turn largely responsible for higher levels of milk production.

Animal Feed↗
PubMed1978

The utilization of diets containing acetate, propionate or butyrate salts by growing lambs.

1. In a comparative slaughter experiment growing lambs were given concentrate diets in which 7, 15 or 22% of the metabolizable energy (ME) provided by barley was replaced by sodium and calcium salts of acetic acid, or 22% of ME was replaced by Na and Ca salts of propionic or butyric acids. 2. The efficiency of utilization for fattening (kf) of the diets containing 0, 7, 15 or 22% of ME as acetate was 57.2, 59.6, 54.1 and 48.8 (SE +/- 1.8) respectively, the last value being significantly lower (P less than 0.001) than the first. The kf for successive increments of acetate was 90, 37 and 19% (SE +/ 3), the decrease being significant (P less than 0.001). 3. The kf value of the diets containing 22% of ME as propionate or butyrate respectively were 48.7 and 50.6 (SE +/- 1.8), both values being significantly lower than the control (P less than 0.01). The partial kf of propionate was 19 +/- 13, and of butyrate 28 +/- 13%. 4. It is concluded that the experiment provided evidence that the efficiency with which acetateis utilized for energy retentionis not constant, but varies with its contribution to ME. The experiment also provided some evidence that large amounts of propionate and butyrate may be inefficiently utilized by growing lambs, although poor utilization of high levels of volatile fatty acid (VFA) salts per se cannot be entirely excluded.

Acetates↗
PubMed1976

The utilization of diets containing acetate salts by growing lambs as measured by comparative slaughter and respiration calorimetry, together with rumen fermentation.

1. In a comparative slaughter experiment, growing lambs were given concentrate diets in which 14 or 19% metabolizable energy (ME) provided by barley was replaced by sodium, calcium and potassium salts of acetic acid. As the proportion of ME as acetate was increased, energy retention decreased. ME intake was 9271, 9430, and 9217 +/- 67 kJ/d and energy retention was 2698, 2422 and 2280 +/- 71 kJ/d for the diets containong 0, 14 or 19% ME as acetate respectively. There were no differences in protein deposition. The efficiency of utilization of acetate for energy retention (kf) was calculated by difference to be 3 and 10 +/- 13% respectively for the diets containing 14 and 19% ME as acetate.

Acetates↗
PubMed1969

Kale anaemia.

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Anemia, Hemolytic↗