R. Hill

Voluntary food intake of growing pigs given diets containing rapeseed meal, from different types and varieties of rape, as the only protein supplement

The voluntary food intake, during 30 min periods after morning and afternoon feeds and during 24 h, by growing pigs given diets containing rapeseed meal (Rsm) or soya-bean meal (Sbm) as the only protein supplement was determined. One diet was offered at a time and a daily changeover sequence of feeding was followed. Four rapeseed meals were compared, one from seeds of British-grown winter Brassica napus varieties (Brsm) and the others from seeds of the varieties Tower (Trsm), Erglu (Ersm) and Span (Srsm). The effects on feed intake of adding flavouring substances to the Brsm diet were also determined. The flavouring substances were molassine meal, sucrose and four commercially-available substances: P, pig nectar; H, hog nectar; S, sow nectar and A, apple. Intake of the Brsm diet was significantly less than those of the Sbm, Trsm and Ersm diets. Addition to the Brsm diet of molassine meal or sucrose at 50 or 100 g/kg did not improve voluntary feed intake. None of the commercial flavouring substances raised the intake of the Brsm diet to the level of the Sbm diet but they improved intake of the Brsm diet to varying extents. Flavourings H, S and A gave similar improvements which were substantial. The Sbm, Brsm and Trsm diets were each fed ad. lib. to groups of growing pigs continuously for 4 weeks. Weekly feed intakes and weight gains were determined. Feed intakes and weight gains followed closely the intake values obtained in the changeover experiments. The highest values were for the Sbm diet; those for the Trsm diet were slightly lower and those for the Brsm diet were substantially and significantly lower. The glucosinolate, sinapine and tannin contents of the rapeseed meals were determined and the results suggested that voluntary feed intake of diets containing these meals was related to their glucosinolate content, but not to their sinapine or tannin contents.

The voluntary food intake by growing pigs of diets containing 'treated' rapeseed meals or extracts of rapeseed meal.

The intake by growing pigs of a diet containing British rapeseed meal (Brsm) extracted once with water was greater than that of a similar diet containing untreated Brsm, and a diet containing Brsm extracted twice with water was eaten more readily than one containing Brsm extracted once with water. Treatment of Brsm with slaked lime increased slightly its acceptability by growing pigs. The addition of a water extract of Brsm to a soya-bean meal (Sbm) diet reduced voluntary intake compared with the voluntary intake of the same Sbm diet with water added. Addition to the diet of a water extract passed through an anion exchange column increased food intake but if a cation exchange column was used there was no effect on intake. Treated rapeseed meals and extracts were analysed for glucosinolates, sinapine and tannins; the results indicated that glucosinolates rather than sinapine or tannin were associated with low feed intake.

The influence of a low-nutrient intake after mating on gestation and perinatal survival of lambs.

Abstract The effects of a low-nutrient intake during the first trimester of gestation on inutero and perinatal survival of lambs were investigated in Blackface ewes. The ewes were all in good condition (score 3 to 3 1 2 ) at the start of the experiment. The treatment group (T, 15 ewes) was given about 15% of the recommended nutrient allowances for maintenance during 60 days post mating. The control group (C, 10 ewes) was given the full maintenance allowance for the same period. At other times ewes in both groups received equal and adequate levels of nutrients. The T group lost almost 9 kg live-weight on average during the restricted feeding period and lost 0·8 unit in condition. There was some compensatory weight gain after the regime finished, but the T ewes were still a little lighter than their original live-weight by parturition. There was no evidence of embryo mortality as a result of the restricted regime. However, lambs from the experimental ewes were less viable, had a lower birth-weight and showed evidence of intrauterine growth retardation. Plasma progesterone profiles showed evidence of elevated levels in the T ewes during days 20 to 25 post coitum , significantly higher than those of the C ewes.

Manganese in the nutrition and metabolism of the pullet. 1. Shell thickness and manganese content of eggs from birds given a diet of low or high manganese content.

1. The first two experiments were similar; pullets were given either a low-manganese diet, 6–7 μg/g, or a high-Mn diet containing an additional 50 μgMn/g; shell thickness as measured by weight per unit area was obtained for the first four and the last four eggs produced during a short laying period and the Mn contents of the first two and last two eggs were determined. 2. Shell thickness was significantly reduced by the low-Mn diet in Expt 1, but not in Expt 2. In both experiments there was an increase in thickness from the first four to the last four shells produced. 3. The Mn content of eggs from birds given the low-Mn diet was significantly lower in both experiments than that from birds given the high-Mn diet. In Expt 1 there was an increase in Mn content from the first to the last eggs laid, but no corresponding change occurred in Expt 2. 4. The differences between the results of the two experiments are discussed; they were probably due to differences in the time for which the experimental diets were given before laying began. 5. In Expt 3 pullets were given the high-Mn or low-Mn diet from about 4 weeks before laying began or the high-Mn diet to the point-of-lay and then the low-Mn diet. Shell thickness was determined in batches of six eggs from each bird at intervals during a 6- to 7-month laying period. 6. Shell thickness was depressed by the low-Mn diet in birds given this diet 4 weeks before laying but not in those given the low-Mn diet from the point-of-lay. 7. In Expt 4 shell thickness was determined on the first thirty eggs laid by four pullets given the high-Mn diet and four given the low-Mn diet from about 4 weeks before starting to lay. The difference between shells from birds given the high-Mn and low-Mn diets just failed to reach significance and there was no significant increase or decrease in the series of thirty shells from each bird, studied in successive groups of six shells.

The Effects of Feeding Kale to Breeding Ewes

SUMMARY 1. Three groups of 12 Welsh Mountain ewes were fed for about ten weeks on either hay and concentrates, or kale fertilized with either nitrochalk or nitrate of soda. Feed intakes were recorded. 2. Blood samples were taken at intervals for determination of copper, haemoglobin, red cell count, packed cell volume and plasma total and protein-bound iodine. About six weeks after the start of the experiment samples were taken by biopsy, of liver for determination of copper content and cytochrome oxidase activity, and thyroid for iodine content and histological observations. Further samples (blood, liver and thyroid) were obtained for analysis when the ewes were killed at the end of the experiment. 3. Throughout the experimental feeding period observations were made of the duration of oestrus in each ewe; at about seven weeks the ewes were tupped and at post-mortem the ovaries and reproductive tracts were removed for observations on numbers of corpora lutea and condition of the embryos. 4. The appetite of kale-fed ewes fell markedly after about five weeks but recovered when a small supplement of concentrates was given. 5. Anaemia occurred in kale-fed ewes: this was most marked after about six weeks and improved towards the end of the experiment. There was no significant effect on blood copper concentration but at post-mortem liver copper values were significantly lower for kale-fed than for control ewes. Towards the end of the experiment there was a significant goitrogenic, effect in kale-fed ewes. 6. The duration of oestrus was significantly reduced in ewes fed kale. 7. Six ewes “returned” after tupping, one in the control group, one in one kale group and four in the other. At post-mortem there were 12 normal embryos in the control group, 8 in one kale group and 9 in the other. The assessment of these data as a depression of reproductive efficiency by kale is discussed. 8. No differences were observed between the effects of kale fertilized with nitrochalk and those of kale fertilized with nitrate of soda.

Voluntary food intake in a limited time of lambs and calves given diets containing rapeseed meal from different types and varieties of rape, and rapeseed meal treated to reduce the glucosinolate concentration

The voluntary food intake in a limited period, 30 or 60 min after morning and afternoon feeds, and during 24 h, by lambs and calves given diets containing rapeseed meal (RSM) or soya bean meal (SBM) as the only protein supplement was determined. Four rapeseed meals were compared, one from seed of British-grown winter Brassica napus varieties (BRSM), and the others from seeds of the varieties Tower (TRSM) and Loras (LRSM), or from seeds of Canadian spring sown varieties (Canola; CRSM). The effects on food intake of treating BRSM with heat and ammonia, steam, steam and ammonia, or calcium hydroxide and ammonia were also determined. In lambs, intakes in a limited period of BRSM and CRSM were significantly lower than that of SBM, and there were no differences between intakes of BRSM and CRSM. In calves, intake in a limited period of BRSM was significantly lower than intake of SBM, TRSM and LRSM: those of TRSM and LRSM were lower, but not significantly so, than that of SBM. Treatment of BRSM with steam, steam and ammonia or calcium hydroxide and ammonia, increased food intake significantly but by small amounts: intakes of the treated meal diets were markedly lower than that of the control SBM diet. The glucosinolate concentration of untreated RSM influenced intake in calves but not in lambs. The effects of treatment of RSM on intake were not closely related to changes in glucosinolate concentration.

THE RETENTION OF AN ORAL DOSE OF RADIOACTIVE MANGANESE IN THE PULLET AND THE EFFECTS ON RETENTION OF THE INTAKE OF INACTIVE MANGANESE.

In the growing chick a large proportion, over 95 yo, of an oral dose of radioactive manganese was found in droppings collected during 72 h after dosing (Mohamed & Greenberg, 1943), indicating a very low retention of this element. The object of the study now presented was to make similar determinations of retention in the laying pullet and to observe the effects on retention of (I) giving a low-Mn diet for 10 weeks or more and (2) varying the quantity of inactive Mn with the radioactive dose. I t soon became evident that retention was very small in all treatments and in consequence, even if differences among treatments occurred, they were unlikely to be detected by the ‘difference method’. Therefore treatment effects were sought in the quantities of radioactive Mn present in the liver and blood. A brief report of part of the work has been published (Hill, 1964).

The effect of pregnancy and sodium intake on water and electrolyte balance in sheep

Abstract Sodium, potassium and water balance were studied throughout pregnancy in sheep on diets providing 1 mmol/kg body weight/d (H) or 0·1 mmol/kg body weight/d (L) of sodium, as well as non-pregnant controls. The polydipsia of pregnancy preceded the polyuria and the latter was greater in twin pregnancies. Faecal water loss also increased. Water turnover was particularly high in sheep excreting the majority of their sodium in urine rather than faeces; they also had greater total sodium loss at the end of pregnancy on the L diet. Sodium conservation was sustained throughout pregnancy on L diets but on H diets the increased output of urine and faeces led to increased sodium losses beyond day 90. Aldosterone secretion rose to a peak around day 100 in L sheep but was suppressed throughout pregnancy in H sheep, suggesting that this level of intake was well above requirement. The results are discussed in relation to the fluid and electrolyte physiology of pregnancy and the dietary sodium requirement.

Studies on rapeseed meal from different varieties of rape in the diets of gilts. II. Effects on farrowing performance of gilts, performance of their piglets to weaning and subsequent conception of the gilts.

Gilts were fed from about 25 kg live-weight on diets containing either rapeseed meal (Rsm) or soyabean meal (Sbm) as the sole protein supplement. Two rapeseed meals from seed of B. napus varieties were compared, those currently grown in Britain (Brsm) and Tower (Trsm) grown in Canada. The effect of these dietary treatments on the reproductive performance during the first parity of the gilts and the performance of their litters to weaning was assessed. The mean weight of live piglets at birth was significantly (P < 0·05) lower for those born to gilts given Brsm (1·24 kg) than those born to gilts given either Sbm (1·35 kg) or Trsm (1·37 kg). The number of piglets born alive per litter did not differ significantly among groups and the differences in birth-weight diminished during the suckling period so that by three weeks of age there were no significant differences among dietary treatment groups in either number of piglets alive or in their weights. The interval between weaning and first observed oestrus was significantly shorter for gilts given the Brsm diet than those given the Sbm diet but there were no significant differences among treatment groups in the interval between weaning and conception.

Studies on rapeseed meal from different varieties of rape in the diets of gilts. I. Effects on attainment of puberty, ovulation rate, conception and embryo survival of the first litter

Gilts were fed from about 25 kg live-weight on diets containing either rapeseed meal (Rsm) or soyabean meal (Sbm) as the sole protein supplement. Three rapeseed meals from seed of different B. napus varieties were compared: (i) those currently grown in Britain (Brsm), (ii) Tower (Trsm), grown in Canada and (iii) Erglu (Ersm), grown in Germany. The influence of these dietary treatments on the early phases of reproduction was assessed from records of age and weight at puberty and conception, ovulation rate and embryo survival. There were no significant effects of any of the Rsm diets on any aspect of the early stages of reproduction except ovulation rate, measured as number of corpora lutea. This number for Brsm (15·3) was significantly greater (P < 0·01) than those for Sbm (13·0) and Trsm (12·6); it was 14·5 for gilts given Ersm. However, there were no significant differences in the number of live embryos at about 34 days for Sbm, Brsm, Trsm and Ersm, means were 11·1, 10·5, 9·3 and 9·9 respectively.