High Plane Of Nutrition Research Articles

The effect of the oral administration of melatonin at two times of the year on ovarian activity in ewes

It has previously been shown (Robinson et al., 1985) that the normal breeding season of Greyface and Scottish Blackface ewes can be advanced by the daily administration of the indoleamine melatonin; the administration of the melatonin beginning midway during the anoestrous period. If melatonin is administered towards the end of the normal breeding season, oestrous activity can be extended, but only for a period of about six weeks until the ewe becomes refractory to the melatonin treatment (Nett and Niswender, 1981). There is no information on the administration of melatonin at the beginning of the anoestrous period.In the following experiments we report results for the influence on the subsequent breeding activity of Greyface ewes of the oral administration of melatonin at the beginning of their normal period of anoestrus. We also report the results of an investigation on the effects of melatonin in advancing the breeding season of Scottish Blackface ewes maintained on either a high or low plane of nutrition. The experiments were carried out under natural daylength conditions at 57°N.

The effect of plane of nutrition and type of diet offered to yearling Friesian steers during a winter store period on subsequent performance

ABSTRACTThree randomized block experiments, involving a total of 80 castrated male cattle, were carried out to examine the effects of plane of nutrition and type of diet offered during a winter store period from about 10 to 15 months of age on the subsequent performance of late-maturing, Friesian steers slaughtered at 22 to 23 months of age. A control diet of medium-quality grass silage (mean digestible organic matter in the dry matter (DOMD) 0·617) offered ad libitum and supplemented with 0·3 kg concentrates (17·1 to 25·6 g nitrogen per kg dry matter) per head daily, which was designed to sustain a live-weight gain of 0·4 kg/day, was compared with three diets which were designed to sustain a live-weight gain of 0·7 kg/day. These were medium-quality silage supplemented with 1·6 kg concentrates, medium-quality silage supplemented with 0·6 kg concentrates and 0·25 kg fish meal and high-quality silage (mean DOMD 0·704) supplemented with 0·3 kg concentrates. The animals were at pasture for 5 months after the treatment period and were then given silage and concentrates for 3 months until slaughter. The low and high planes of nutrition sustained mean daily live-weight gains of 0·43 and 0·73 kg respectively, giving a difference in live weight at the end of the treatment period of 45 kg. Compensatory growth at pasture reduced this difference to 30 kg. This resulted in a difference of 17 kg carcass weight between the two planes of nutrition. The type of diet offered at the high plane of nutrition did not affect subsequent performance. It is concluded that, when the live-weight gain of late-maturing, Friesian, yearling cattle was reduced below about 0·7 kg/day, there was relatively little compensatory growth during the subsequent period at pasture and consequently the optimum live-weight gain during the winter for this type of animal may be higher than that previously recommended.

Effect of diet and temperature acclimation on thermoregulatory behaviour in piglets

Piglets were weaned at 14 days and acclimated to 10 or 35°C and kept either on a low or a high plane of nutrition. After 2 and 3 weeks of acclimation their operant thermoregulatory behaviour was observed at 15°C. The pigs which had been living at 10°C obtained more radiant heat than those from 35°C and the animals on a low energy intake obtained more reinforcements than those on a high intake. There was no interaction between temperature and diet indicating that these two variables exerted their influence independently. Pigs tested 22 hr after a meal obtained more heat than when tested 1 hr after a meal. Rectal temperature before the test was significantly lower in the animals reared at 10 than at 35°C, but the difference had disappeared at the end of the trial. By contrast, the pigs kept on different planes of nutrition had the same rectal temperatures before the test trial but afterwards the animals on a high diet had higher rectal temperatures. Body temperatures seemed to be the factor which influenced the demand for heat. The role of thermal comfort, body size, diet induced thermogenesis and separate sets of controls for autonomic and behavioural thermoregulatory responses in operant thermoregulatory behaviour is discussed.

A dietary etiology for osteochondrotic cartilage

Samples of distal lateral radial growth plate cartilage were serially harvested from weanling Thoroughbreds after 0,3,6 and 9 months on diets providing either 100% or 130% of energy and protein requirements. The higher plane of nutrition was associated with decreased cartilage hexosamine and hydroxyproline contents and increased DNA contents. Similar observations followed the postmortem harvesting of humeral and radial articular cartilages after 9 months. These findings are consistent with previous reports suggesting that high-energy diets induce osteochondrotic changes in the cartilage of weanling horses.

Comparisons of Control and Selected Strains, Strain Crosses, and Commercial Stocks of Leghorns for Egg Production Efficiency

Abstract Agriculture Canada Animal Research Centre Leghorn Strains 1 and 8, selected for a number of economically important traits but primarily for early egg production rate and egg numbers respectively, were compared with their respective unselected controls, Strains 5 and 7, two reciprocal crosses of the selected strains, designated 18 and 81 (sire strain shown first), and a commercial stock. Two diets (high and low protein with similar protein:energy ratios) were fed during the testing of these stocks. Birds on the higher plane of nutrition consumed less feed and produced eggs with a slightly higher proportion of yolk; however, these birds were less efficient on the basis of solids and gross energy output: intake and egg yield: feed intake. Selected strains produced more large eggs that had a higher percentage of egg white solids and a lower proportion of yolk than their respective control strains. Strain 1 showed generally greater differences in comparison with its control than Strain 8. In general, feed efficiencies were higher in the selected strains than in their respective controls. The strain crosses exceeded the parental strains in egg production, egg weight, and several measures of feed efficiency. Reciprocal effects were observed in egg weight, egg yield, and efficiency. Egg production of the commercial stock ranked between the two crosses. This study provided evidence that multitrait selection for high egg production and related commercially important traits increases the efficiency of egg production and influences egg composition. Improvements from strain crossing were due mainly to increases in egg production and egg size.

Pre-pubertal mammogenesis in the sheep 1. The effects of level of nutrition on growth and mammary development in female lambs

AbstractFemale lambs were given a high energy and high protein diet in varying amounts to achieve either high (H; 220 g/day) or low (L; 110 g/day) rates of gain during two consecutive periods between 4 and 20 and 20 and 36 weeks of age. The effects on body growth and mammary gland development were compared by slaughtering an initial group of four lambs at 4 weeks of age (mean live weight 11 kg), eight L lambs (24 kg) and eight H lambs (33 kg) at 20 weeks of age, and eight LL lambs (36 kg), eight LH lambs (49 kg) and eight HL lambs (48 kg) at about 36 weeks of age.At slaughter, a single mammary fat pad from each lamb was trimmed and weighed, and the deoxyribonucleic acid (DNA) content of the portion containing parenchyma determined. The mean weight (g) and DNA content (mg) were: 4-week-old lambs, 8·6 g, 1·5 mg; L, 14·7 g, 32·3 mg; H, 30·0 g, 25·9 mg; LL, 46·0 g, 61·2 mg; LH, 86·7 g, 91·0 mg; HL, 70·3 g, 73·0 mg respectively. Relative growth coefficients for mammary parenchyma, estimated from the increase in DNA relative to that for live weight, were 3·7 and 2·4 for L and H lambs respectively, between 4 and 20 weeks, and 1·6, 1·4 and 2·6 for LL, LH and HL lambs respectively, between 20 and 36 weeks of age.These results are consistent with the hypothesis that a high plane of nutrition can decrease the rate of allometric growth of mammary parenchyma before puberty. However, the cessation of this growth phase was not related to the attainment of puberty, or of a specific live weight or age, but may be related to the availability of mammary fat pad tissue limiting further parenchymal development after 20 weeks of age.

Changes in the body composition of cattle exhibiting compensatory growth and the modifying effects of grazing management

AbstractFriesian steer calves born in August were reared from 3 to 7 months of age on either a low (OL) or high (OH) plane of nutrition. A further group born in October (YH) was also reared on a high plane. At grazing, the performance of calves of the same age but different weights (OL v. OH) or the same weight but different ages (OL v. YH) were compared at two levels of herbage allowance, either 30 or 60 kg dry matter per kg live weight. During the winter, the H groups received silage and concentrate and the L group was given silage only. The OL group had a higher concentration of fat and a lower concentration of water in the empty body at the end of the winter than did the OH and YH groups respectively.Compensatory growth was exhibited by the OL group at both herbage allowances. Differences in the live-weight and empty body-weight gains of OL and OH cattle could be explained almost entirely by differences in the energy content of the gains whereas this was only partially so when the OL and YH groups were compared. The results indicate that YH cattle had lower herbage intakes even though they were of similar weight to OL cattle.It was concluded that silage nitrogen is used less efficiently by cattle than is generally assumed and that the levels of gut fill and energy content of the live-weight gains in this experiment were not consistent with the general values suggested by the Agricultural Research Council (1980).

Variations in Density and Chemical Composition of White-Tailed Deer Antlers

Eighteen sets of cast antlers were collected from seven male white-tailed deer, Odocoileus virginianus , maintained on a high nutritional plane. Density and chemical compositional differences were found to occur among deer and as a result of age and portion of antler analyzed. Antler density varied among deer, tended to decrease with age, and was lower along the length of the main beam than along the tines or at the antler tips. Chemical composition also varied among deer. Various elements were affected in differing ways by increases in age. Possible physiological and morphological reasons for these differences are discussed and a hypothesis regarding their behavioral significance is proposed.

Effect of Plane of Nutrition from Starting Through the Breeder Period on the Reproductive Performance of Tom Turkeys

Large type breeder toms were given high (HP) or low (LP) planes of nutrition from hatching to 29 weeks of age. Birds from each rearing treatment were divided and HP or LP breeder rations were fed to 58 weeks. Protein and energy levels of the HP feeds approximated National Research Council (NRC, 1977) recommendations while LP feeds involved substitution of corn, fat, and soybean meal for wheat, barley, and oats. Energy-protein ratio and relative essential amino acid levels were similar between treatments, respective of age.Toms given LP feeds weighed less than HP through the first 9 weeks after hatching, but they were similar thereafter until 29 weeks. Reduction in feed conversion with the LP regimen was only significant during the 18 to 21-week interval. Feed intake during the breeder period was unaffected by treatments. Toms receiving the LP breeder feed reduced their weight, particularly when preceded by LP rearing. Mortality was inversely related to average body weight with each treatment. Reproductive capacity, as judged from semen yield and sperm concentration, was more favorable when toms were reared on LP than HP feeds but only during the first few weeks of the breeder period. The LP feed given through the breeder period also proved more favorable than HP feed, particularly at the end of production. Carcass evaluations at 29 and 58 weeks indicated that the LP regimens reduced depot fat while increasing relative testes weight.

Effects of maternal nutrition on the availability of energy in the body reserves of fetuses at term and in colostrum from Scottish Blackface ewes with twin lambs

Ewes carrying twin fetuses were maintained during late pregnancy on a uniformly high plane (n = 22), a uniformly low plane (LP) (n = 24) or a low plane increasing to a high plane (n = 14) of nutrition. Seven ewes at each nutritional level were killed at 142 days of gestation and the liver and muscle glycogen and body lipid concentrations of the fetuses were determined. The rest of the ewes lambed naturally at about 145 days and the colostrum yields were obtained by hand milking after oxytocin injections during the first 18 hours after birth. The lactose, lipid and protein concentrations of colostrum were determined. Undernutrition in the LP group did not apparently affect the body concentrations of available glycogen, reduced available body lipid by about 47 per cent and reduced the lactose, lipid and protein available in colostrum during the first 18 hours by about 50 per cent. Refeeding previously underfed ewes to a high plane during the last five to 10 days of pregnancy did not improve the available reserves of glycogen or lipid in the lambs but did increase the yields of colostral constituents by about 30 per cent. The relative contributions of body reserves and colostral constituents to the maintenance of high, medium and low metabolic rates in lambs from different groups was assessed. It was concluded that under normal field conditions refeeding undernourished ewes during the last weeks of pregnancy would improve only marginally the survival potential of the lambs and that most lambs would be compelled to draw on their body glycogen reserves in order to maintain heat production during the first 18 hours after birth, even when they consumed all the available colostrum.

An interaction between season of calving and nutrition on the resumption of ovarian cycles in post-partum beef cattle.

Angus cows were first mated at approximately 27 months of age in 2 herds, calving 21 July to 15 September (Group E) or 9 September to 30 October (Group L). The cows were fed a high (H) or medium (M) plane of nutrition for 55 days before and 40 days after calving. There was a mean liveweight difference of 35 kg between cows in Groups EH + LH and Groups EM + LM immediately after calving and at 40 days after calving. Immediately after calving cows in Groups EH + EM were 11 kg heavier than cows in Groups LH + LM, but there was no difference at 40 days after calving. There was a significant interaction between calving time and nutrition in the return of cyclic ovarian function assessed from both interval to first oestrus and first elevated progesterone concentration. Mean intervals from calving to first oestrus were 66.7, 82.7, 56.7 and 62.3 days in Groups EH, EM, LH and LM respectively. These data demonstrate that season of calving influences resumption of ovarian cycles even at a constant high plane of nutrition and that season of calving interacts with nutrition such that effects of season are more likely to be expressed under conditions of low nutrition.

Seasonal variation of red blood cell survival in desert bighorn sheep (Ovis canadensis cremnobates)

The life-span of red blood cells (RBCs) in captive and free-ranging desert bighorn sheep was measured with [32P]diisopropylfluorophosphate. The mean winter RBC life-span (156.6 days) was not significantly affected by season for captive animals maintained on a high nutritional plane and water, ad libitum. Free-ranging bighorn demonstrated a significant (P < 0.001) difference between mean winter (155.9 days) and summer (203.9 days) RBC survival. Dehydration of captive bighorn significantly increased RBC survival, closely approximating that found in summer free-ranging animals. Desert bighorn RBCs exhibited an aseasonal facultative response to the availability of water. RBC life-span was significantly (P < 0.05) increased from 153.5 to 197.7 days in animals experiencing extreme dehydration. The large spleen, relative to body weight, may accommodate extensive fluctuations in total RBC volume measured during dehydration and rehydration, preventing premature RBC degradation and an increased water requirement.

Carcass composition and mammary development responses to photoperiod and plane of nutrition in Holstein heifers.

Twenty prepubertal heifers (averaging 155 kg body weight) were assigned to one of four treatment groups in an experiment of 2 X 2 factorial design. The main effects were photoperiods of 8 h light:16 h dark (8L:16D) vs 16L:8D, and LOW vs HIGH plane of nutrition. Heifers on the LOW plane of nutrition were fed to achieve a growth rate of approximately .7 kg/d; daily feed intake was restricted with no orts and was identical in both groups of heifers subjected to either 8 or 16 h of light daily. Heifers on the HIGH plane of nutrition were fed ad libitum to achieve a growth rate greater than 1 kg/d. All heifers were slaughtered during the luteal phase of an estrous cycle at an average body weight of 337, 334, 360 and 349 kg for 8L:16D-LOW plane, 16L:8D-LOW plane, 8L:16D-HIGH plane and 16L:8D-HIGH plane groups, respectively. Average time on treatment was 233, 236, 206 and 181 d and average estimated carcass weight gain was .39, .40, .55 and .61 kg/d, respectively. Within LOW or HIGH planes of nutrition, photoperiod did not affect live body weight gains. A photoperiod of 16L:8D, compared with 8L:16D, increased protein content in the 9-10-11th rib section of heifers on HIGH nutrition (16.2 vs 14.6%), but not in heifers fed the LOW plane of nutrition (15.5 vs 16.1%). However, within 8L:16D groups, HIGH plane reduced rib section protein content as compared with LOW plane of nutrition (14.6 vs 16.1%); there was no difference observed within 16L:8D groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of different stocking intensities in early life on the productivity of Merino ewes grazed as adults at two stocking rates. 2. Reproductive performance

The reproductive performance of ewes subjected to four nutritional regimes from conception to 15 months of age was recorded from first lambing at 24 months until the seventh lambing. The ewes were grazed at 10 and 20 sheep/ha. The proportion of ewes which exhibited oestrus at their first mating was less in those which had grazed at a high stocking rate between 3 and 15 months, and fecundity was increased by 15% in subsequent years by a high plane of nutrition between conception and 3 months of age, but only when ewes were grazed at a low stocking rate as adults. Ewes stocked at 10 sheep/ha weaned 50% more lambs than ewes stocked at 20 sheep/ha in adult life, but the more heavily stocked ewes weaned approximately 33% more lambs on a unit area basis. Approximately half the variability in the number of lambs weaned per ewe available for service was associated with variability in lamb survival. Relationships between the proportion of ewes showing oestrus, fecundity, survival of lambs, overall reproductive performance and liveweight of ewes are presented.

A study of the relationship between plane of nutrition during lactation and certain production characteristics in autumn-calving suckler cows

ABSTRACTHereford ♂ × British Friesian ♀ cows that had calved in September/October and were suckling mainly Charolais ♂ × calves were offered individually one of three planes of nutrition based on their estimated maintenance requirement during their first 150 days of lactation.The mean daily intakes of metabolizable energy were 95·8, 71·5 and 52·1 MJ for the high, medium and low planes of nutrition respectively. Data were collected from 122 lactations. The mean 150-day cumulative milk yields of the cows were 1 355, 1 258 and 1 187 kg for the high, medium and low planes of nutrition respectively (P < 0·001). A i-kg increase in calf birth weight was associated with an increase in 150-day cumulative milk yield of 14·7 ± 2·17 kg (P < 0·001). Losses in live weight and condition score were significantly greater for cows given the low plane of nutrition during lactation (P < 0001).Although there was a significant (P < 0·01) positive correlation between the growth rate of the calves and their dams' nutritional level during the winter there was evidence of compensatory growth at grass, since by the time of weaning in August, the plane of nutrition of the dam during the winter had no significant effect on the weight of the calves.The experiment demonstrates that energy-deficient beef cows will attempt to maintain milk production at the expense of body reserves and that when supplementary solid food is made available to the suckled calves, their weaning weights are unaffected by the plane of nutrition of the dam during the winter.

The growth and carcass characteristics of crosses between Aabio and Tegal ducks and Muscovy and Pekin drakes

1. The growth and food utilisation of Pekin, Alabio and crosses between Muscovy or Pekin drakes and Alabio or Tegal ducks were recorded up to 20 weeks of age on a high plane of nutrition. Ducks were killed at 6, 10 and 16 weeks of age for carcass analysis. 2. The weight of Alabio ducks at 12 weeks of age was increased by 40 and 48% by crossing with Muscovy and Pekin respectively. Pekin crosses grew faster to 8 or 12 weeks of age than Muscovy crosses but after 17 weeks of age there was no significant difference in weight. Food utilisation for Muscovy crosses was generally better at all ages. 3. Both at a given age and per unit of carcass weight, Muscovy crosses contained less fat and as a consequence more protein and ash, and a higher proportion of breast meat than Pekin crosses. Proportion of fat in Muscovy × Tegal ducks increased only slightly with carcass weight, while it decreased in Muscovy × Alabio ducks.

The effect of winter nutrition on growth of young Scottish Red deer (Cervus elaphus)

Compared with European Red deer, Scottish Red deer stags are remarkably small. Previous research has shown that this may be primarily due to nutritional, rather than genetic reasons. The present study tested the hypothesis that poor nutrition, especially during the first winter of life, prevented the stags from reaching their genetic potential size. The study was carried out at Glensaugh Research Station on 20 newly weaned Red deer assigned to either of two groups, one fed a high plane of nutrition during the winter, the other a low plane. The trial began in December 1977 and in May 1978 both groups were released into a 200 acre paddock. In September 1978 some of each group were slaughtered. Despite considerable compensation by the low plane winter nutrition group there were significant differences in live weight, antler length and carcass weight at slaughter. It is considered that Scottish Red deer stags reach the maximum size that the environment can maintain despite this being far below their genetic potential.

Effects of Plane of Nutrition on Organ Size and Fasting Heat Production in Genetically Obese and Lean Pigs

Fifteen obese and 15 lean pigs with an initial weight of 27 kg, three from each of five litters, were randomly assigned within litter to three treatments. The first treatment group (HL) was fed to gain 19 kg body weight during the first 35 days (period 1) and to lose 5 kg during the second 35 days (period 2). The second treatment group (MM) was fed to gain 7 kg during both periods 1 and 2. The third treatment group (LH) was fed to lose 5 kg during period 1 and to gain 19 kg during period 2. At the end of the 70-day period, all pigs were fasted for 30 hours, and fasting heat production (FHP) was measured by indirect calorimetry. The animals were slaughtered, and weights of stomach, small and large intestines, liver, pancreas, spleen, kidneys and heart were measured. Although all animals had the same final body weight, both obese and lean pigs on the higher plane of nutrition during period 2 had significantly higher FHP and higher weights for stomach, small and large intestines, pancreas, liver and kidneys. Lean pigs had significantly higher weights for stomach, large intestine, pancreas, heart, and spleen than their obese counterparts with no significant difference detected for small intestine, liver and kidneys. Statistical analyses did not reveal any difference between lean and obese pigs for FHP even though lean pigs on MM and LH treatments had 17 and 15% higher FHP values than obese pigs from the same treatment groups. Significant and positive correlations exist between FHP and weights of stomach, small intestine, large intestine, pancreas, liver and kidneys. These results indicate that prior nutritional history significantly influences FHP, which is highly correlated to weights of metabolically active organs for both genetically obese and lean pigs.

Influence of a Low Plane of Nutrition During Sexual Development on Subsequent Reproductive Performance of Small White Breeder Toms

Diamond White and Wrolstad breeder toms were reared to 10 weeks of age on a common nutritional regimen. Both strains were subsequently given high and low planes of nutrition to 30 weeks. Low nutrient feeds were ca. 200 kcal of metabolizable energy (ME)/kg less than high nutrient feeds, which paralleled commercial practice. Energy-protein ratio and essential amino acid profiles between nutrient levels were similar. Both planes were phased down ca. 200 kcal ME/kg between the feeds from 10 to 14 weeks to 14 to 30 weeks. All birds subsequently received the same breeder ration.Diamond Whites were heavier than Wrolstads from 2 through 10 weeks of age. Feeding the low plane of nutrition reduced body weight of both strains at 14 weeks. Growth during the 14- to 30-week-period was such that birds given the low plane feeds recovered earlier losses, and Wrolstads became heavier than Diamond Whites. Although no differences in body weight occurred throughout the breeder period that could be attributed to earlier nutrition, the low plane feeds led to significant improvements in semen and sperm yield during the early and late stages. Wrolstads accrued more fat and benefited more from the low plane of nutrition than did Diamond Whites. Results inferred that reducing fat accretion early in sexual maturity improves subsequent reproductive capacity apart from an alteration in body weight.

Influence of pre- and post-partum nutrition on LH secretion in suckled postpartum beef heifers

The influence of nutrition during the last trimester of pregnancy and the early postpartum period on postpartum LH secretion was evaluated in two-year-old Hereford and Simmental heifers maintained on a high or low plane of nutrition (experiment 1) or in Hereford heifers fed a high or low energy (150% vs 100% NRC) ration (experiment 2). Amount of LH released with 10 mg estradiol benzoate (IM) at 14 and 28 days postpartum in experiment 1 or at 14,32,50 and 74 days postpartum in experiment 2 was less (P<.01) for heifers fed the low vs high plane or energy ration and less (P<.05) at 14 days postpartum than at subsequent postpartum periods. The interval from estradiol benzoate injection to the LH peak concentration was longer (P<.05) in Simmental than Hereford heifers, longer (P<.05) in heifers fed the low rather than high energy ration, and longer (P<.01) at 14 days postpartum than at subsequent postpartum periods. The amount of LH released was inversely related to the time required for initiation of the release (r = −.62). Tonic LH secretion was higher (P<.05) in heifers fed the high energy ration and was correlated with average daily gain (r = .75), but was unaffected (P.05) by days postapartum or breed of cattle. Results indicate that increased dietary energy intake increases LH secretion and shortens the anovulatory period in suckled postpartum beef heifers.