Low Plane Of Nutrition Research Articles

The effect of different oestrogens and oestradiol plus progesterone on the growth and carcass characteristics of fattening male hoggets

A comparison has been made in five flocks with a total of 473 sheep of the effect of 15 mg. diethylstilboestrol (DES.) as a paste, 15 mg. hexoestrol as an implant, and 5·0 mg. oestradiol benzoate plus 50 mg. progesterone (O.+P.) as two implants, on the growth rate and slaughter characteristics and carcass grading of fattening male hoggets.In those flocks where the plane of nutrition was adequate, all hormone treatments resulted in a significant increase in live-weight gain. During the first 24–40 days, DES. paste resulted in significantly greater daily live-weight gain compared to hexoestrol or O.+P. in two out of five flocks, but over the whole period there were no significant differences between these treatments. In one flock which was on a lower plane of nutrition there were no significant effects of hormone treatment.The hormone treatments resulted in extra carcass weight, extra pelt weight but no change in killing-out percentage or in carcass grade. There were no significant differences between treatments in the slaughter characteristics studied.

Performance of Laying Hens Subjected to Restricted Feeding During Rearing and Laying Periods

IN RECENT years there has been considerable controversy concerning the merits of rearing replacement stock pullets on a low plane of nutrition. Research reports practically all indicate a delay in sexual maturity when nutrient intake is limited but there is much less agreement as to the effect on subsequent laying-house performance. This can be attributed, at least in part, to different methods and severity of restriction and also to variations in length of restriction periods.Tests concerned with an actual restriction in feed intake were reported by Milby and Sherwood (1953), Singsen et al. (1954), and Milby and Sherwood (1956). Other than delaying sexual maturity from 10 to 26 days, restricted feeding had no real influence on subsequent egg production, mortality, over-all feed consumption, final body weight or average egg weight. Similar results were obtained by Sunde et al. (1954), when comparing a complete growing diet with a diet containing …

The effect of environmental temperature on the energy metabolism of cattle

1. A relatively inexpensive closed-circuit respiration chamber for cattle is described.2. Experiments with two steers are reported in which heat production and energy retention data were measured at different levels of food intake and at different environmental temperatures.3. The energy lost in faeces increased with improving plane of nutrition but was not significantly affected by the environmental temperature. Urine energy losses fell with increasing environmental temperature at low planes of nutrition. Methane losses increased with improving nutritional plane but were reduced by high environmental temperatures at high levels of food intake.4. The heat production of fasting animals, or animals on low planes of nutrition was not influenced by the environmental temperature in the range 20–40° C. On higher planes of nutrition an increasing environmental temperature increased the animals' heat production.5. The major factor determining energy retention in different environments is the heat production of the animal. Net energy values consequently vary with temperature.

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude I. The annual fluctuation in body temperature and body temperature increase between 6.30 a.m. and 12.30 p.m.

Early morning and midday body temperatures of rams and ewes of three breeds of sheep were measured once weekly for a period of 10 months in Northern Rhodesia and 12 months in Southern Rhodesia.1. In all breeds seasonal fluctuations in body temperature were due to concurrent fluctuations in ambient air temperature.2. Mean annual body temperatures were: Merino 102·2° F.; Persian 101·7° F. and Native 101·7° F. Wool and hair breeds differed considerably in their early morning temperatures and in their body temperature increases from 6.30 a.m. to 12.30 p.m. Mean annual values for these measurements were Merino 101·73 and 1·92° F.; Persian 100·81 and 1·83° F.; Native 100·73 and 1–92° F. At all times Merinos showed markedly greater uniformity of body temperature than either hair breed. There was no evidence to show that the thermoregulatory mechanisms of these animals had been stressed unduly.3. Sex had no consistent effect on body temperature or on rise in body temperature.In general, lactating ewes showed a significantly higher initial body temperature than either empty or pregnant ewes, but the respective heat tolerances as measured by body temperature increase did not differ appreciably. Body temperature differed little in empty and pregnant ewes.4. Although the youngest group of ewes in each breed showed the highest early morning temperature, there was no evidence that heat tolerance was less in young than in old animals.5. Black-coated Native ewes had higher initial body temperatures and a smaller body temperature increase during the summer months in Southern Rhodesia than brown or broken-coloured Native ewes. These effects were due to differences in coat density rather than to differences in coat colour or skin pigmentation.6. In all breeds the magnitude of the diurnal and annual variation in body temperature was different in Northern and Southern Rhodesia. Differences were largely of climatic origin but low plane of nutrition in Southern Rhodesia possibly reduced critical body temperature and impaired thermoregulatory ability.

The effect of the plane of energy nutrition of the cow during the late winter-feeding period on the changes in the solids-not-fat content of milk during the spring-grazing period

SummaryThree groups of eight Friesian cows, four of high and four of low milk yield, were given during the last month of the winter-feeding period rations that provided respectively low, normal and high planes of energy nutrition, at approximately 75,100 and 130% of the Woodman standards for starch equivalent (S.E.). They were then all changed to the grazing of good, spring pasture, without supplementary food. The changes with grazing in solids-not-fat (S.N.F.) content and yield of milk were markedly influenced by the previous level of winter feeding. After 15–18 days of grazing the mean changes in S.N.F. percentage were +0·33, +0·11 and –0·12 for the low, normal and high energy groups, and the corresponding changes in milk yield were +7·70, +2·13 and –0·68 lb per cow per day. The changes in S.N.F. reflected mainly changes in protein content, and to these casein, β-lacto-globulin and α-lactalbumin all contributed. Small, differential changes were found in the fat and lactose contents of the milk. The effects of the level of initial milk yield of the cow on the various responses to grazing are recorded.These observations support the view that when a rise in S.N.F. with spring grazing occurs it probably results from an improvement in the plane of energy nutrition. There appears to be no need to postulate a special effect of any specific herbage constituent.

Nutrition in relation to reproduction in sows

Gilts of the ‘Palouse’ breed were divided into two groups; one group was full fed from weaning to 1501b. and the other group was fed 70% of full feeding. After six generations, one-half of the pigs in each group were shifted to the other plane of nutrition, thus forming four groups: high-high (HH), low-high (LH), low-low (LL) and high-low (HL). F10 gilts were slaughtered 38 or 100 days post-coitum to study reproductive and prenatal phenomena.1. Ten successive generations of controlled feeding had no significant effect on: length of Fallopian tubes, weight of corpus luteum, percentage of implantation, number of viable foetuses, foetus weight, weight of placental membranes, volume of placental fluids or embryonic mortality.2. There were significant differences between the high and low planes of nutrition in: weight of pituitary, thyroid and adrenals, weaning weight, puberty weight, puberty weight to birth weight, puberty weight to weaning weight and puberty age. The effect of six generations of controlled feeding was not maintained when the plane of nutrition was changed from high to low or low to high.3. The frequency of silent heat and the number of services per conception was lower in the low planes than in the high planes.4. Ova migration occurred in both directions in 41% of the gilts; one to four ova migrated. The foetal sex ratio ranged from 4:0 to 1:7 with an average of 1:1. The sexes were unevenly distributed in the horns.5. Foetus weight at 38 or 100 days post-coitum was not affected by plane of nutrition or sequence in the uterine horn.6. Within-litter variations were highest in the volume of allantoic fluid followed in order by variations in weight of placental membranes and then the amniotic fluid and foetus.7. Foetal mortality was not related to sequence in the uterine horn or the number of implantations.8. There seemed to be two peaks of early prenatal mortality, one at implantation and another at the onset of organo-genesis.

Selection of mice for growth on high and low planes of nutrition

1. Two-way selection was applied to the growth of mice between 3 and 6 weeks of age when reared on a high plane of nutrition and, in another pair of lines, when reared on a low plane of nutrition. In each generation the growth of all four lines was measured on both high and low planes of nutrition.2. Growth on the two planes of nutrition was treated as two different characters and the direct and correlated responses of each were estimated. The genetic correlation between the two characters was estimated from the responses of each of the four lines, and from the divergence between upward-and downward-selected lines. The different estimates should be the same if the theory of selection for correlated characters adequately accounts for the responses. Up to generation 7 the agreement was reasonably good, but in the later generations it was not. Four estimates of the genetic correlation up to generation 7 were: 0·75, 0·19, 0·66, 0·57.3. There was asymmetry between the upward and downward responses, and the realized heritabilities changed over the course of the experiment; so also did the phenotypic variation. In all these respects the lines behaved differently.4. The conclusions drawn from the final responses are summarized at the beginning of the Discussion.5. The mice produced by selection for increased growth on low plane, but later reared on high plane, were compared with those produced by selection on high plane. Their growth was the same, but they were heavier, had less fat and more protein, and were better mothers.

Infertility and neonatal mortality in the sow III. Neonatal mortality and foetal development

1. An analysis of pre-weaning mortality in inbred Large White pigs showed that the over-all mortality in ten generations of sows was 47·3%. During the first four generations mortality fluctuated between 30 and 45%; from the 5th to the 9th it fluctuated between 50 and 68% and in the 10th rose to 88%.2. 70·2% of all deaths occurred in the first 3 days post-parturition and the average birth weight of pigs which died within 3 days was only 1003·5 g. compared with 1258·5 g. for those which survived. 83·0% of pigs weighing less than 900 g. at birth died within 3 days, whereas only 18·5% of pigs weighing more than 1400 g. died within the same period.3. There were marked seasonal variations in mortality, this being highest during the winter months. Mortality was highest in litters of under 5 and over 15, but between 5 and 15 there was no increase in mortality with litter size. There was no difference in mortality between males and females.4. Foetal growth was studied in 80 outbred sows of various breeds. Foetal weight was affected not only by age but also by litter size. The withinlitter variation in foetal weight increased with litter size but no increase in between-litter variation with litter size could be demonstrated statistically. Male foetuses were slightly heavier than females at all stages of pregnancy investigated.5. The growth of the inbred Large White foetus was also studied at an early and late stage of inbreeding, and the reduced birth weight in the latter was shown to be reflected in slower growth of the foetus from mid-pregnancy onwards.6. The anatomical composition of inbred Large White foetuses at a late stage of inbreeding has been compared with that of similar foetuses at an earlier stage and also with normal outbred Essex foetuses, at 51, 74, 97 and 108 days of pregnancy. The chemical composition of inbred Large White foetuses of a later stage of inbreeding was compared with that of outbred Essex foetuses at 51, 74, 97 and 108 days. The differences in anatomical composition between the smallest and largest foetuses within litters are comparable with those found postnatally in pigs fed on a high or low plane of nutrition, but this was not reflected in a very definite way in the chemical composition. X-ray photographs showed that ossification was more advanced in the largest foetus within a litter than in the smallest but the appearance of the ossification centres was not delayed in the latter.7. Attempts to make reciprocal ovum transfers between inbred Large White and outbred Essex sows met with little success, probably due to the low fertility of the Large Whites, the prolonged exposure of the ovum during transference and the necessity of effecting the transfer of the ova at the 2-cell stage. The latter was conditioned by the rate of passage of the ova through the tube and the fact that they enter the uterus in the 4-cell stage.

A Relationship between Weight of Internal Fat, ‘Fill’, and the Herbage Intake of Grazing Cattle

A SERIAL slaughter technique was used in 1956, 1957 and 1958 to study ‘fill’ and carcass changes on spring pasture. Hereford cross-bred steers, aged 2–2½ years, which had been subjected to different winter treatments were used. In each year, four separate groups of cattle were over-wintered on a high or a low plane of nutrition, in yards and outside in paddocks. Differences varying from an average of ¾ to 1½ cwt. per head were obtained in the different years between high and low plane groups by the end of winter. The low plane groups were fed less silage than the high groups, more straw, and no concentrates, to gain an average per head of ¼ cwt. in one year to 1½ cwt. in another, from January until April.

Genotype-environment interactions in the wintering of lambs

An experiment to investigate the differential response of lambs of various breeds and crosses to different planes of nutrition is described.Two groups of twin lambs were used comprising Blackfaces and their crosses ( x Lincoln, Wiltshire and Border Leicester rams) and Welsh and their osses ( x Suffolk and Wiltshire rams).From October to January, each cross was divided between high and low planes of nutrition. Approximately half of the twin pairs were split and the remaining pairs distributed between the environments. Significant differences were found between the crosses and twin pairs of the same cross for body weight, body measurements and wool production but not for various blood characters. For almost all characters studied, plane differences were found. There was, however, only one significant (P < 1%) cross-plane interaction—for non-protein nitrogen concentration in the blood.At the end of January, each plane was subdivided to produce high-high, high-low, low-high and low-low groups. The lambs remained in these groups until May. As before, differences between crosses were found for body weights and measurements, and wool characters but not for most blood characters. The majority of characters were affected by plane of nutrition. Cross-plane interactions were not found except in antibody response toErisipelothrix rhusiopathiavaccine (P < 5%).At the end of May the high-high group were slaughtered and the remaining three groups fattened on grass until each reached the same average weight as the high-high group. Carcass measurements showed that all the crosses shared a striking ability to recover from previous poor nutritional treatments. One significant (P < 5%) interaction of cross and plane was found in weight of cannon bone.The most characteristic feature of the results has been the similarity of response of the different genotypes to the different nutritional environments. The few interactions found to be statistically significant by conventional methods are difficult to interpret because of the many tests of significance carried out in the analyses.

The effect of plane of nutrition during rearing on growth, production, reproduction and health of dairy cattle. I. Growth to 24 months

1. Eighteen pairs of one-egg and 6 pairs of two-egg twin calves were used in a balanced incomplete block design to examine four systems of rearing: (1) a continuous high plane of nutrition from birth to first calving (HH); (2) a high plane for the first 44 weeks followed by a low plane until 2 months before calving (HL); (3) a continuous low plane until 2 months before calving (LL); and (4) a low plane to 44 weeks followed by a high plane to first calving (LH). All animals were fed on a high plane during the two months before calving.2. Mean daily consumptions of DM, TDN, S.E. and DCP are given and the net energy intakes compared with a recently recommended standard.3. At 44, 80 and 104 weeks of age there were highly significant differences between the groups in all weights and measurements due to treatment. Low-plane feeding retarded the growth of the skeleton to only a limited extent as compared with live-weight. After the changeover, animals on the HL system lost much of the advantage in body measurements they had gained over those fed on a continuous low plane.4. All groups reached sexual maturity at the same stage of physical development but at different ages. The HL animals were the slowest to attain maturity indicating that as with growth the changeover from a high plane to a low plane of nutrition had had an adverse effect.5. Low-plane animals on poor hill pasture made better growth than their mates on good arable pasture. Evidence is presented, however, to show that part of this greater growth in live-weight was due to increased ‘fill’.

Live weight loss and its components in Romney ewes subjected to L-thyroxine therapy and a low plane of nutrition. Part II. Effects on some non-carcass components of live weight

1. The effects of l-thyroxine therapy and a low plane of nutrition on some of the non-carcass components of live weight in New Zealand Romney ewes were investigated.2. Thyroxine treatment significantly lowered the weight of the gastrointestinal tract contents. A low plane of nutrition and a longer total starvation immediately pre-slaughter had little effect in lowering the weight of the gastrointestinal contents. Alimentary tract ‘fill’ accounted for a group mean loss of live weight of up to 5 lb.3. Thyroxine treatment lowered the weight of the empty gastric tract, while a low plane of nutrition reduced the weight of both the empty gastric and intestinal tracts. The combined treatment effects accounted for a loss of up to 3 lb. in the weight of the empty gastrointestinal tract.4. Neither treatment significantly reduced the weight of the omental and mesenteric fat depots.5. The weight of the thyroid gland was unaffected by either treatment.6. A low plane of nutrition significantly reduced the weight of the liver, kidneys and the heart but had no effect on the weight of the spleen. Thyroxine therapy significantly reduced the weight of the liver and tended to increase the weight of the kidneys and the heart.

Live weight loss and its components in Romney ewes subjected to L-thyroxine therapy and a low plane of nutrition. Part I. Effects on live weight, carcass weight and carcass composition

1. An experiment involving fifty Romney ewes of known history is described. These ewes were randomized to ten treatment groups of five ewes so that group mean live weights were approximately equal. The average live weight of the ewes was 147 lb. at selection and 135.5 lb. at the beginning of the 28-day experimental period. Three levels of L-thyroxine implants, viz. 150, 210 and 270 mg. were used on six groups of ewes, three of which (LT: NP, MT: NP, HT: NP) were on a normal plane of nutrition and three (LT: LP, MT: LP, HT: LP) on a low plane of nutrition. One group of ewes (DT: LP) was daily injected with 5 mg. L-thyroxine; one group of ewes (CB) was slaughtered at the commencement of the 2 8-day experimental period; one group of ewes (C:NP) was maintained for 28 days on a normal plane of nutrition and did not receive thyroxine therapy, and another group of ewes (C:LP) was on a low plane of nutrition for 28 days and was not treated with thyroxine.2. Live-weight losses of up to 24.4 lb. for the low thyroxine (150 mg.) low-plane group of ewes (LT:LP) and 30.0 lb. for the three surviving ewes of the DT: LP group were recorded at the end of the 28-day experimental period. The daily injection of 5 mg. L-thyroxine treatment had to be modified because of two deaths.

Foetal dwarfism in sheep—an effect of high atmospheric temperature during gestation

The course of pregnancy was followed in three groups of Peppin-strain Merino ewes. Group 1 of seven ewes, maintained on a high plane of nutrition, all lambed; the mean birth weight of lambs was 8 lb. 6 oz. The six ewes in group 2, kept on a low plane of nutrition, all lambed; the mean birth weight of their lambs was 1 lb. 9 oz. lower (P<0·01). The seven ewes in group 3 kept on a low plane of nutrition and subjected daily to temperatures of 112° F. dry bulb, 92° F. wet bulb, produced only four lambs; the mean birth weight was 4 lb. 6 oz. less than those from group 1, and 2 lb. 13 oz. less than those from group 2 (P < 0·001).Scale photographs of the lambs, and X-rays and measurements of their long bones, after dissection, showed that the lambs of group 3 were miniatures: their skeletons were much reduced in size, whereas low nutrition alone (group 2), caused little skeletal reduction.The mechanism of dwarfing is not clear. However, fore-cannon bone lengths and liver weights, considered in relation to lamb birth weights indicated that it was not a nutritional effect.This study was undertaken at the Physiology Department, University of Queensland. It is a pleasure to thank Prof. W. V. Macfarlane for the valuable facilities, and for his help and encouragement.

The influence of selection and plane of nutrition on the components of fleece weight in Merino sheep

The components of clean fleece weight were examined in five experimental flocks of medium-wool Peppin Merinos. Four single-character selection groups – clean fleece weight plus, clean fleece weight minus, crimps per inch plus, and crimps per inch minus – were examined by measuring fleece production in 18-month-old ewe progeny. Measurements were also made on progeny from the "nucleus" flock, which was selected for clean fleece weight with subsidiary selection for crimps per inch and against fold score. Data were collected in 1952 and 1954. The 1954 figures were obtained from a nutrition experiment in which sheep mere grown from weaning to 18 months on a high and on a low plane of nutrition. The mean measurements of the components of clean fleece weight (W) were compared between flocks using the "percentage deviation" technique. Four comparisons were made: (1) Nucleus/Fleece minus; (2) Fleece plus/Fleece minus; (3) Crimps minus/Crimps plus; (4) high nutritional plane/low nutritional plane. In comparisons (1) , (2), and (3), difference in weight of wool per unit area of skin (w) accounted for nearly all the difference in W. Body weight (S) made a small contribution while difference in fold score (R) was negligible. Fibre density (N) accounted for +86 per cent., and fibre cross-sectional area (A) for –28 per cent., of the difference in W in comparison (1). In comparison (2) the figures were N +47 per cent., A +21 per cent., while the figures for comparison (3) were N –26 per cent., A +121 per cent. The increase in fleece weight was invariably accompanied by a decrease in crimps per inch. In all three comparisons primary density (P) was the major cause of change in N. Fibre length (L) made a uniform contribution of approximately +15 per cent. in the three comparisons.The relative importance of the components of fleece weight was similar at both high and low levels of nutrition.The effect of a high level of nutrition was to produce large increases in A, L, and S. The increase in S was compensated by an equal decrease in P. The increase in fibre diameter was not associated with any change in crimps per inch.

The Effect of Dietary Fat Level on Thyroid Activity in the Growing Chick

ABSTRACT SINGH and Shaffner (1950) found that increasing the calorie content of the diet appeared to raise metabolic rate in the chick. Mellen, Hill and Dukes (1954) reported that the fasting oxygen consumption of male chickens reared on a diet containing 975 Calories per pound was higher than that of similar chicks fed a diet containing only 505 Calories per pound. In the above experiments the diets at the lower energy level were suboptimal in energy and consequently may be considered to represent a low plane of nutrition. There do not, however, appear to be data regarding the effect of high energy levels on the basal metabolic rate of chickens. There have been studies on rats in which the effects of different levels of fat were investigated. Panos and Finerty (1953 Panos and Finerty (1954) found a relative decrease in the weight of the thyroid glands in rats fed fat-deficient diets, and other investigators . . .

THE EFFECT OF AGE AND THE PLANE OF NUTRITION ON THE BLOOD CHEMISTRY OF THE COLUMBIAN BLACK-TAILED DEER (ODOCOILEUS HEMIONUS COLUMBIANUS): B. BLOOD GLUCOSE, NON-PROTEIN NITROGEN, TOTAL PLASMA PROTEIN, PLASMA ALBUMIN, GLOBULIN, AND FIBRINOGEN

The blood sugar, non-protein nitrogen, total plasma protein, plasma albumin, globulin, and fibrinogen of the Columbian black-tailed deer have been studied on two series of animals reared on high and low planes of nutrition from birth to 465 days of age. Of these blood constituents only blood sugar and fibrinogen showed a measurable lowering in the low plane animals. Age changes have been noted that are independent of nutritive state but are similar to those reported for domestic ruminants.

Maternal influences on litter size in pigs

The effects of inbreeding of the sow and plane of nutrition after mating on litter size at 28 days were investigated.Outbred Large White sows were mated at first heat after weaning to inbred boars, and inbred sows to outbred boars, so that both groups of sows carried the same type of embryo. The sows were then placed at random on either high or low planes of nutrition until slaughter 28 days later, when their corpora lutea and number of embryos were counted.Litter size was significantly higher in outbred than in inbred sows by 2·52 ± 0·93 pigs. This resulted from 2·89 ± 0·94 more ova shed and 0·37 ± 0·93 more embryos dying. The general conclusion is that inbreeding of the sow reduces early litter size mainly by depressing ovulation rate.The different planes of nutrition produced negligible differences in within-litter mortality and, therefore, on litter size, but resulted in a marked difference in conception rate. All animals on the high plane were pregnant, whereas on the low plane 25% were empty, this difference being highly significant.Age of the sow, but not her weight, was found to be significantly correlated with number of corpora lutea (r = 0·39). The latter had a correlation with litter size of 0·55 and with mortality of 0·45. The correlation between litter size and mortality was −0·50.Parity increased and inbreeding reduced the length of the uterus which was not, however, significantly correlated with litter size.

Influence of nutrition upon duration of gestation in sheep.

VARIOUS effects of different planes of nutrition on pregnancy in the ewe have been studied; but there appears to be no record of an effect on duration of gestation. Four series1 of observations were made, in which Merino ewes were maintained on high, medium and low planes of nutrition from the 108th, 129th, 136th or 143rd day of pregnancy to parturition. The distribution of the treatments among the four series is shown in Table 1. Prior to the experimental nutritional period, ewes had either been maintaining or gaining weight. During the experimental period, the ewes on the low plane in series 4 and 6 received chaffed wheaten hay only. All other ewes received a mixture of equal parts of oats and chaffed legume hay, with or without pasture. Ewes on the high plane of nutrition in each instance were allowed access to food ad lib. and gained about 0.2–0.4 kgm. in weight per head per day. In each series the ewes on the low plane of nutrition received about 0.2 kgm. (dry weight) of food per day each and lost about 0.2–0.4 kgm. in weight per day. Ewes on the medium plane received sufficient food to maintain, constant body-weight.

The effect of high and low planes of nutrition on the haematology of monozygous twin calves

1. In an experiment conducted with eight pairs of monozygous twin heifer calves aged from 7 to 9 months, it was shown that the mean haemoglobin concentration of those reared on a high plane of nutrition was higher than the corresponding value of those reared on low-plane rations.2. The relative anaemia of the low-plane animals was microcytic but normochromic in type. Its cause must await further investigation, but these features would not be inconsistent with a deficiency of iron.3. For this type of haematological study, monozygous twins proved more efficient than unrelated animals, as shown by the smaller variability within than between pairs.4. Day-to-day variation in the same animal must be considered an important possible source of sampling error.