Low Metabolizable Energy Research Articles

Utilizing different ratios of alfalfa and layer ration for molt induction and performance in commercial laying hens

Molting is a common practice used by the commercial egg industry to rejuvenate flocks for a second or third laying cycle. During this time the hens rest from production, and the reproductive organs are rejuvenated to increase production and quality during the next laying cycle. Although feed withdrawal (FW) is the most popular and effective method of molt induction, it has come under scrutiny due to food safety issues and animal welfare issues. This study involved feeding alfalfa mixed with layer ration at different ratios to hens to determine their ability to induce molt. The treatment ratios were 100% alfalfa (A100), 90% alfalfa and 10% layer ration (A90), and 70% alfalfa and 30% layer ration (A70). In addition, a fully fed (FF) nonmolted control and a FW negative control were used. Alfalfa is an insoluble, high fiber feedstuff with low metabolizable energy. Egg production for A90 and FW treatments ceased completely by d 6, whereas birds fed A100 and A70 ceased egg production by d 8. Ovary and oviduct weight of hens fed all molting diets decreased (P < 0.05) by an average of 1.5 to 2.5% (BW basis) compared with FF control during the 9-d molt induction period. As the percentage of layer ration increased, feed intake also increased and percentage of BW loss decreased during the 9-d molt induction period. Hens molted by FW lost an average of 25.8% BW, whereas A70 hens lost 18.9% BW. Nonmolted hens (FF) and A70 treatment hens had significantly lower (P < 0.05) egg production when compared with all other treatments over the 39-wk postmolt period. FF treatment hens also had lower (P < 0.05) albumen heights when compared with all other treatments. From these results, alfalfa or alfalfa mixed with layer ration appears to be viable alternatives to conventional FW methods for the successful induction of molt and retention of postmolt performance.

Alfalfa as a single dietary source for molt induction in laying hens

Molting is a process by which a hen’s reproductive tract is rejuvenated prior to the beginning of a laying cycle. This process is often artificially induced in commercial settings in order to extend the productive life of a flock of hens. The most common method for the induction of molt is feed withdrawal for a period of several days. It has been noted that feed withdrawal, while effective in inducing molt and allowing an adequate reproductive rest period for the hen, may cause deleterious effects on the animal. This has prompted the investigation of alternatives to feed deprivation for the induction of molt in commercial laying hens. This study involved feeding alfalfa to hens to assess its ability to induce molt. Results show that alfalfa meal and alfalfa pelleted diets were equally effective as feed withdrawal in causing ovary weight regression in birds. Molted hens induced by alfalfa diets exhibited postmolt levels of egg production over a twelve week period that were similar to that of hens molted by feed withdrawal. The postmolt eggs laid by hens molted by alfalfa were of comparable quality to eggs from feed deprived hens. Alfalfa, a fibrous feed with low metabolizable energy, may be provided to hens on an ad libitum basis for an effective molt induction that retains comparable egg quality and production.

High leptin in pregnant mink (Mustela vison) may exert anorexigenic effects: a permissive factor for rapid increase in food intake during lactation.

The role for leptin in food intake regulation in the mink, a polytocous seasonal breeder with altricial young, was investigated in pregnant and lactating dams and data were related to quantitative energy metabolism measurements and plasma concentrations of other important metabolic hormones. A total of nine mink dams were measured in consecutive 1-week balance periods, each including a 22 h measurement of heat production by means of indirect calorimetry, and blood was sampled at weekly intervals throughout gestation and during lactation weeks 1-4. Intake of metabolisable energy (ME) was high and energy balance was positive until the first third of true gestation. During mid- and late gestation ME intake decreased (P<0.001) while heat production remained almost constant, resulting in negative energy balance and the loss of body weight. From late gestation until lactation week 4, ME intake increased by 3.5 times, but weight loss continued. Plasma concentrations of leptin were approximately doubled during the last two-thirds of true gestation (P<0.01), demonstrating a clear gestational hyperleptinaemia. Concentrations declined rapidly after parturition and then remained stable. Insulin was independent of leptin, with low concentrations coincident with hyperleptinaemia. Also, concentrations of thyroid hormones declined during gestation, probably reflecting the low food intake. Hyperleptinaemia concomitant with low ME intake, negative energy balance and mobilisation of body reserves suggested an anorexigenic effect of leptin in pregnant mink. This suppression of food intake in late gestation might be permissive for the rapid increase in food intake occurring after parturition.

Effects of nutrition and management on the production and composition of milk fat and protein: a review

The composition and functional properties of cow’s milk are of considerable importance to the dairy farmer, manufacturer, and consumer. Broadly, there are 3 options for altering the composition and/or functional properties of milk: cow nutrition and management, cow genetics, and dairy manufacturing technologies. This review considers the effects of nutrition and management on the composition and production of milk fat and protein, and the relevance of these effects to the feeding systems used in the Australian dairy industry. Dairy cows on herbage-based diets derive fatty acids for milk fat synthesis from the diet/rumen microorganisms (400–450 g/kg), from adipose tissues (&lt;100 g/kg), and from de novo synthesis in the mammary gland (about 500 g/kg). However, the relative contributions of these sources of fatty acids to milk fat production are highly dependent upon feed intake, diet composition, and stage of lactation. Feed intake, the amount of starch relative to fibre, the amount and composition of long chain fatty acids in the diet, and energy balance are particularly important. Significant differences in these factors exist between pasture-based dairy production systems and those based on total mixed ration, leading to differences in milk fat composition between the two. High intakes of starch are associated with higher levels of de novo synthesis of fat in the mammary gland, resulting in milk fat with a higher concentration of saturated fatty acids. In contrast, higher intakes of polyunsaturated fatty acids from pasture and/or lipid supplements result in higher concentrations of unsaturated fatty acids, particularly oleate, trans-vaccenate, and conjugated linoleic acid (CLA) in milk fat. A decline in milk fat concentration associated with increased feeding with starch-based concentrates can be attributed to changes in the ratios of lipogenic to glucogenic volatile fatty acids produced in the rumen. Milk fat depression, however, is likely the result of increased rates of production of long chain fatty acids containing a trans-10 double bond in the rumen, in particular trans-10 18 : 1 and trans-10-cis-12 18 : 2 in response to diets that contain a high concentration of polyunsaturated fatty acids and/or starch. Low rumen fluid pH can also be a factor. The concentration and composition of protein in milk are largely unresponsive to variation in nutrition and management. Exceptions to this are the effects of very low intakes of metabolisable energy (ME) and/or metabolisable protein (MP) on the concentration of total protein in milk, and the effects of feeding with supplements that contain organic Se on the concentration of Se, as selenoprotein, in milk. In general, the first limitation for the synthesis of milk protein in Australian dairy production systems is availability of ME since pasture usually provides an excess of MP. However, low concentrations of protein in milk produced in Queensland and Western Australia, associated with seasonal variations in the nutritional value of herbage, may be a response to low intakes of both ME and MP. Stage of lactation is important in determining milk protein concentration, but has little influence on protein composition. The exception to this is in very late lactation where stage of lactation and low ME intake can interact to reduce the casein fraction and increase the whey fraction in milk and, consequently, reduce the yield of cheese per unit of milk. Milk and dairy products could also provide significant amounts of Se, as selenoproteins, in human diets. Feeding organic Se supplements to dairy cows grazing pastures that are low in Se may also benefit cow health. Research into targetted feeding strategies that make use of feed supplements including oil seeds, vegetable and fish oils, and organic Se supplements would increase the management options available to dairy farmers for the production of milks that differ in their composition. Given appropriate market signals, milk could be produced with lower concentrations of fat or higher levels of unsaturated fats, including CLA, and/or high concentrations of selenoproteins. This has the potential to allow the farmer to find a higher value market for milk and improve the competitiveness of the dairy manufacturer by enabling better matching of the supply of dairy products to the demands of the market.

Effect of chromium propionate and metabolizable energy on growth, carcass traits, and pork quality of growing-finishing pigs.

An experiment was conducted to evaluate the dietary effects of Cr propionate (CrProp) and metabolizable energy (ME) on growth, carcass traits, and pork quality of growing-finishing pigs. One hundred forty-four Cambrough-22 barrows were allotted to four dietary treatments in a randomized complete block design (six replicates of six pigs per replicate; average initial and final body weight were 27 and 113 kg, respectively). The dietary treatments were: 1) corn-soybean meal basal (B; low ME), 2) B + 200 ppb of Cr (as CrProp), 3) B + 200 kcal ME/kg (4.5% added fat; high ME), or 4) B + 200 kcal ME/kg + 200 ppb of Cr. At trial termination, three pigs per replicate were killed to determine dietary effects on carcass traits and pork quality. Overall average daily gain, average daily feed intake, and gain:feed ratio were not affected (P > 0.10) by diet. During the early growing period, average daily gain was increased in pigs fed the CrProp-low-ME diets, but decreased in pigs fed the CrProp-high ME diets (Cr x ME, P < 0.04). Feed intake was increased (P < 0.05) in pigs fed the high-ME diets during the early growing period. Forty-five min and 24 h pH were not affected (P > 0.10) by diet. The CIE L* tended (P = 0.07) to be increased and shear force tended (P = 0.06) to be decreased in pigs fed high-ME diets. Subjective marbling was increased (P < 0.03) and longissimus muscle percentage moisture and thaw loss were decreased (P < 0.04) in pigs fed CrProp. Chromium propionate had no consistent effect on growth and carcass traits in this experiment; however, CrProp did affect some aspects of pork quality.

Progesterone clearance rate in lactating dairy cows with two levels of dry matter and metabolisable energy intakes

The aim of these studies was to determine the effect of levels of dry matter (DM) and metabolisable energy (ME) intakes on clearance rate of progesterone (P4) in dairy cows. Thirty-two lactating Holstein–Friesian cows were selected for the study and were fed indoors in individual stalls for a period of 5 weeks. They were individually offered a diet of combinations of pasture, hay and pelleted cereal grain to achieve two different levels of DM and ME. In the first trial, 16 cows were allocated to two groups: (i) high DM (HDM), and (ii) low DM (LDM) intakes, while the amount of ME intake was constant. In the second trial, 16 cows were allocated to two groups: (i) high ME, and (ii) low ME intakes with similar amount of DM intake. A GnRH-agonist (deslorelin) was initially implanted in the ear of each cow to block endogenous P4 secretion. Then 3 weeks later, a CIDR device was inserted into the vagina of each cow and left in place for 11 days. Chromic oxide (Cr 2O 3) capsules were administered to allow daily faecal output (FO) to be estimated. Daily blood, faecal and milk samples were taken during the period of the experiment for P4 and faecal P4 metabolites analyses. Trial 1: The average milk yield was similar among cows in high and LDM intake groups (26.7 versus 25.0 l per day, P=0.2). The average daily FO was 7.8 kg DM in the HDM and 5.7 in the LDM cows ( P<0.0001). Average daily DM intakes were 17.3 kg and 15.4 kg in the HDM and LDM groups, respectively ( P<0.0001). The average plasma P4 concentrations were similar between the two groups (1.56 versus 1.60 ng/ml, P=0.7) but milk P4 concentrations were higher in LDM cows (4.6 versus 3.6 ng/ml, P=0.02). The average daily excretion rate of P4 into the milk was higher in LDM cows (122.3 versus 88.5 μg, P=0.002). The concentrations of faecal P4 metabolites (FP4M) were not influenced by the level of daily DM intake (2.85 versus 2.90 μg/g, P=0.6). The average daily yields of FP4M were higher among cows in the HDM group (23.2 versus 16.3 mg, P=0.01). Trial 2: The average milk yield was 31.2 l per day in HME cows compared to 25.0 l per day in LME cows ( P<0.0001). The average daily FO was 7.8 kg DM in LME and 5.8 kg DM in HME cows ( P<0.0001), and the average DM content of faeces was higher in LME cows (15.8 versus 12.7%, P=0.01). The average daily ME intake was 213 MJ per day in HME group compared to 183 MJ per day in LME group ( P<0.0001). The average plasma and milk P4 concentrations were similar between the two groups (plasma P4=1.54 versus 1.56 ng/ml, P=0.4; milk P4: 3.7 versus 3.6 ng/ml, P=0.6). The average daily excretion rate of P4 into the milk was higher in HME cows (114 versus 88.5 μg, P=0.03). Concentrations of FP4M were not influenced by the level of daily ME intake (2.5 versus 2.85 μg/g, P=0.08). However, daily yields of FP4M were greater in the LME group (23.2 versus 14.4 mg, P=0.01). In conclusion, this study was unable to establish a relationship between the level of DM and ME in the diet with the excretion rates of FP4M metabolites and plasma P4 concentrations.

Suplementação da Silagem de Sorgo com Diferentes Fontes de Proteína para Bovinos de Corte

Farelo de soja (FS), farinha de penas (FPH) e farelo de soja tratado (FST) com 0,17% de formaldeído foram utilizados como suplementos à silagem de sorgo para avaliar os seus efeitos sobre o consumo, o desempenho e a digestibilidade aparente dos nutrientes em bovinos machos. O tratamento do farelo de soja com formaldeído não diferiu do farelo de soja não tratado para todos os ítens estudados. Por outro lado, a farinha de penas apresentou menores coeficientes de digestibilidade para a MS, MO, PB, FDN e FDA (63,0; 64,9; 61,80; 56,4; e 50,9% versus 65,1; 67,0; 66,8; 58,5; e 53,6% do FS e 66,7; 68,7; 67,2; 61,9; e 57,5% do FST, respectivamente), além de propiciar menor consumo de energia metabolizável por unidade de tamanho metabólico (214 kcal/UTM para a FPH, 234 kcal/UTM para o FS e de 240 kcal/UTM para o FST). Mesmo com estas diferenças nos parâmetros acima mencionados, não foi possível detectar diferenças para o ganho de peso dos animais, de 1,5; 1,6 e 1,7 kg/dia para FPH, FS e FST, respectivamente.

Effect of level of grain supplementation on milk production responses of dairy cows in mid - late lactation when grazing irrigated pastures high in paspalum (Paspalum dilatatum Poir.)

Two grazing experiments tested the hypothesis that a cereal grain-based supplement, fed to cows that are in mid–late lactation and grazing low metabolisable energy and high neutral detergent fibre content paspalum (Paspalum dilatatum Poir.)-type pastures, will increase milk yield, but that this response will diminish with successive increments of supplement. A further objective of this research was to investigate some of the factors, such as altered rumen fermentation pattern, that might vary the point at which diminishing returns start to occur. Cows grazed irrigated perennial pasture at an allowance of either 25 (experiment 1) or 31 (experiment 3) kg of dry matter (DM) per cow per day in late summer–early autumn (mid–late lactation) and were supplemented with cereal grain-based concentrates up to 11 and 7 kg DM/cow.day in experiments 1 and 3, respectively. In experiment 1, there were 3 replicates of 6 treatments (3 cows in each treatment group) that involved the feeding of either 0, 3, 5, 7, 9 or 11 kg DM/cow.day of supplement for 50 days. Experiment 3 was conducted over 35 days. There were 2 replicates of 4 treatments (4 cows per treatment group) that involved the feeding of either 0, 3, 5 or 7 kg DM/cow.day of supplement. A further experiment (experiment 2), associated with experiment 1, examined the effects of offering cereal grain-based concentrates up to 7 kg DM/cow.day to dairy cows consuming 10 kg DM/day of herbage with a high paspalum content on aspects of rumen fermentation. Incremental responses of 40 g/kg fat-corrected milk (FCM) to increasing concentrate intake diminished with increasing concentrate intake, with the level of supplementation at which diminishing returns occurred dependent on herbage allowance and, therefore, herbage intake. At a supplement intake of 3 kg DM/cow.day, the response in FCM was 1.1 kg/kg concentrate DM in both grazing experiments. There were no further increases in milk production with additional increments of concentrates in experiment 3 where the pasture allowance was highest. In experiment 1, where concentrates were offered to a level of 11 kg DM/cow.day, and the pasture allowance was lower, diminishing returns were not as pronounced as in experiment 3 until the highest levels of concentrate intake. Substitution of supplement for herbage was a major factor in causing the diminishing returns in both experiments, but especially in experiment 3, where pasture intakes were higher. Milk fat content was significantly (P&lt;0.05) reduced (41.8 v. 32.5 g/kg) when concentrate intake increased from 9 to 10.4 kg supplement DM/cow.day in experiment 1. It was hypothesised that this reduction in milk fat content was probably due to the effects of subclinical rumen lactic acidosis. This hypothesis was supported by the trend to lower rumen pH for longer periods as supplement intake increased as well as a more variable milk yield at the highest level of supplement intake. We conclude that responses of FCM of 1.1 kg/kg DM cereal grain-based concentrates can be achieved when they are fed twice daily up to 3 kg DM/day to dairy cows grazing restricted amounts of paspalum-type pasture in autumn. Beyond 3 kg DM/day, marginal responses diminished with increasing concentrate intake, with the level of supplementation at which diminishing returns occurred being dependent on herbage allowance and, therefore, intake.

The influence of recombinant bovine somatotropin on dietary energy level-related growth of Holstein-Friesian bull calves.

Our objective for this study was to assess the effect of recombinant bovine somatotropin (rbST) in overcoming the biological effects attributed to live weight increase and age on growth and fat deposition in male cattle. Holstein-Friesian bull calves (n = 56; 182.2 +/- 14.7 d old) were allotted to four subtreatments in a randomized complete block with a factorial arrangement of two levels of rbST: 0 and 500 mg of Posilac, every 2 wk, and two dietary metabolizable energy (ME) concentrations: low metabolizable energy (LME) and high metabolizable energy (HME); 10 vs 11.3 MJ/kg DM, respectively. The effect of rbST treatment on daily gain was expressed mostly on the HME diets. The rbST treatment had no effect on the animals fed the LME diets before the age of 240 d was reached. Dry matter intake and the effect of rbST treatment on DM intake were inversely related to the energy concentration of the diet. The degree of fatness of the animals was significantly reduced by rbST treatment and significantly increased by energy concentration of the diet. The major effect of rbST, under the experimental conditions, in regards to adipose tissue deposition, was on the fat depots and not on the intramuscular fat. The concentration of bST, IGF-I, and insulin in the plasma was increased (P < .001) owing to rbST treatment. Lower metabolizable energy supply led to a higher (P < .001) plasma bST concentration, nonsignificantly lower plasma IGF-I and thyroid hormone concentrations, and lower (P < .001) plasma insulin concentration. A trend (P = .065) toward an increase in PUFA was found in the muscle of the rbST-treated and the HME diet animals. At a young age, when the natural growth potential is high, rbST treatment will be efficient only when a diet allowing a high digestible energy intake is provided.

Effects of a xylanase on individual bird variation, starch digestion throughout the intestine, and ileal and caecal volatile fatty acid production in chickens fed wheat

1. The effects of a xylanase on digesta viscosity and starch digestibility throughout the small intestine and volatile fatty acid production in the ileum and caeca were investigated in broilers fed on a low-metabolisable energy wheat diet. 2. The xylanase reduced (P <0.01) duodenal (2.9 vs 1 7), jejunal (4.6 vs 2.3) and ileal (14.0 vs 3.9) digesta viscosities (mPas) and increased AME (P <0 01) of the wheat and starch digestibility (P <0.5) in the jejunum and ileum. Between-bird variability in ME and digestibility of starch was also reduced. 3. Enzyme supplementation reduced (P <0.05) fermentation in the ileum, but increased (P <0.05) it in the caeca. 4. The anti-nutritive effect of soluble non-starch polysaccharides (NSP) is related to their ability to increase digesta viscosity along the gut; this in turn causes changes in gut microflora and efficiency of nutrient utilisation by the chicken. Use of appropriate enzymes is an effective way of dealing with grains with high NSP content in poultry diets.

The effect of late pregnancy on the diet selections made by ewes

To test the hypothesis that sheep select a diet that meets their physiological needs (imposed by late pregnancy), four foods were formulated of either a high metabolisable energy (ME) concentration (A, B 12 MJ/kg dry matter (DM)) or a low concentration (C, D 9 MJ/kg DM). The crude protein (CP) concentrations of A and C were high (279 and 191 g/kg DM) relative to B and D (105 and 95 g/kg DM); the ratios of metabolisable protein: ME were 12 g/MJ for foods A and C and 4 g/MJ for foods B and D. Twin bearing and non pregnant Greyface ewes of similar body condition were offered ad lib., A, B and C as single foods and paired choices (A with B) and (C with D). Replication was a minimum of four ewes for single foods and six for the choices. Food intakes by pregnant and non pregnant ewes were similar until parturition was imminent, when the intakes by the pregnant ewes declined rapidly. The majority of pregnant ewes carried twin foetuses to term without problems. When the ME concentration of the food choice was high (A/B) pregnant ewes selected a greater proportion (P < 0.05) of the food of high CP concentration than non pregnant ewes: pregnant 0.57 (se 0.074); non pregnant 0.28 (se 0.105). By contrast when ewes were offered a choice between foods of low ME concentration diet selection was unaffected by state: proportion of the higher CP food, C selected were: 0.70 (se 0.070) and 0.79 (se 0.069) for pregnant and non pregnant ewes respectively. These results show that when the dietary ME concentration of foods given as a choice is high, pregnant ewes select a diet that reflects their enhanced demand for protein in contrast with non pregnant contemporaries. However, when the ME of the foods is low priorities other than physiological state may motivate their diet selection. It is suggested that such a priority is the maintenance of a balanced rumen environment.

The response of dairy cows given high levels of molasses to dietary levels of fermentable metabolisable energy

Unprotected tallow is used as a feed ingredient to meet the energy requirement of high milking dairy cows, but its hydrolysed free fatty acids in the rumen can inhibit microbial activity and dietary fibre digestion. However, the negative effects of the tallow could be minimized when high levels of molasses are also fed since feeding molasses could shorten the retention time of the hydrolysed free fatty acids in the rumen. In addition, molasses contains a large proportion of non-structural carbohydrates (sugars) which have fast fermentation rates in the rumen. When a diet is formulated to have a low fermentable metabolisable energy (FME) concentration, supplementing with a high molasses level may partially make up the deficiency of the energy requirement of the microorganisms in the rumen of dairy cows. Previous experiments have showed that molasses could be fed to dairy cows up to 312 g/kg DM without adverse effect (Yan and Roberts, 1992) and a crude protein level at 160 g/kg DM in the diet containing 310 g/kg DM of molasses was satisfactory for feed intake and milk production of dairy cows (Yan and Roberts, 1993). The current experiment was subsequently undertaken to investigate the response of dairy cows given high levels of molasses to dietary levels of FME produced by altering unprotected tallow concentrations in diets.

Interrelationships between lack of shading shelter and poultry litter supplementation: food intake, live weight, water metabolism and embryo loss in beef cows grazing dry Mediterranean pasture

AbstractThe objective of the study was to assess the usefulness of providing shade for beef cows grazing summer dry Mediterranean -pasture and supplemented with a food high in non-protein nitrogen (poultry litter). Two groups of 30 cows each, in the last trimester of pregnancy, were placed on 1 June in two paddocks of similar grazing pressure, topography, vegetation cover and botanical composition. In one of the sub-units the cows had free access to a large shaded area, provided by 10 to 12 large eucalyptus trees, whereas in the second sub-unit, access to shade was denied until 31 August. Respiration rate, used as an index of heat stress, was much higher in the non-shaded cows (102 breaths per min) than in the cows with access to shade (62 breaths per min). In response to the much higher heat stress in the non-shaded cows, total body water and haematocrit value (an index of plasma volume) were higher than in the cows with access to shade. Metabolizable energy (ME) intake was apparently much lower in the non-shaded cows, as reflected in a much higher non-esterified fatty acid concentration in plasma. Consequently, large differences in live weight gradually developed during the course of the trial, the cows with access to shade becoming much heavier than those with no access to shade. An increase in the consumption of poultry litter by the non-shaded cows was interpreted as an effort to reduce internal heat load by avoiding grazing and by preferring food which induces a lower heat increment upon ingestion and digestion. Above-normal serum concentrations of cholesterol and alkaline phosphatase support previous results that the combination of low ME intake and high ammonia load induces a toxic effect on the liver. Although all the cows were pregnant at the onset of the study, successful parturition was recorded in 26 of the 30 cows having access to shade, and in only 20 of the 30 (F &lt; 0·05 by t test) of the non-shaded cows. It is concluded that providing shade for beef cows under summer Mediterranean conditions will reduce the danger of embryonic loss. However, an interaction with metabolic burden, such as ammonia load and a negative energy balance, can make the situation much worse.

The performance of ewes offered concentrates containing olive by-products in late pregnancy and lactation

AbstractEwes of the Segureña breed were allocated to groups and were group-fed different diets composed of concentrates and roughage (lucerne hay in experiment 1 and barley straw in experiment 2), in late pregnancy and lactation. The concentrates were formulated with sunflower cake and barley, either alone (control group) or partly replaced with olive cake (OLC) and olive molasses (OLM) in a 5:1 ratio. The OLC was either untreated or was treated with NaOH or ammonia. Concentrates were given to provide proportionately 0·4 and 0·7 of calculated metabolizable energy (ME) requirements in experiments 1 and 2 respectively. In experiment 2 a further group grazed pasture and was given barley at a reduced rate.In experiment 1, the mean ME intake during late pregnancy (5+1 weeks pre-lambing) for all treatment groups was about 796 kj/kg M0·75 per day and largely exceeded their average energy requirements, whereas it was close to requirements (601 kj/kg M0·75 per day) in experiment 2. During lactation, ME intake was adjusted to the theoretical needs for ewes suckling a single lamb (835 to 870 kj/kg M0·75 per day) and was slightly deficient (990 to 1020 kj/kg M0·75 per day) for ewes with twins, irrespective of both treatment (except the group at pasture) and experiment.Minor differences in animal performance, attributed to the type of concentrate offered, were found. In pregnancy, alkali treatment of OLC significantly improved live-weight gains (P &lt; 0·01). Live-weight gains of ewes in experiment 2 were lower than those in experiment 1 in accordance with their lower ME intake, the lowest gains being found in the group at pasture (P &lt; 0·05). Weight losses in lactating ewes in experiment 1 were 17 to 100 and 9 to 165 g per ewe per day for ewes suckling single and twin lambs respectively. In experiment 2 ewes with twins gained weight, while those with single lambs showed little weight change, although differences between experiments were too small to attain statistical significance. No differences in barley straw intake by pregnant ewes were found between treatment groups. However, the intake of barley straw by lactating ewes in the groups offered concentrates containing OLC and OLM was significantly higher than that by controls (P &lt; 0·05).Birth weight of lambs tended to be higher in experiment 2 when ewes consumed less ME during pregnancy, although variations were not statistically significant. The most important cause of growth rate variation was the number of lambs born to a ewe (P &lt; 0·001). The growth rate of lambs in the outdoor group was significantly lower than that of lambs in the indoor groups (P &lt; 0·05).

The apparent digestibility of Atriplex barclayana and its effect on nitrogen balance in sheep

AbstractAn in vivo digestibility trial was conducted by feeding sheep the leaves, fruits and twigs of Atriplex barclayana in a proportion roughly equivalent to that eaten by sheep grazing freely in Atriplex plantations. Four treatments were imposed on each of four sheep in a 4 × 4 Latin-square experimental design: Atriplex offered alone or with 100, 200 or 300 g/day tapioca meal.The mean apparent digestibility of the Atriplex dry matter (DM) and organic matter (OM) consumed were 0·59 and 0·56, respectively. Addition of tapioca to the Atriplex in the diet did not improve these digestibility coefficients. The low OM content of 760 g/kg together with its digestibility of 0·56 resulted in the Atriplex having a low metabolizable energy concentration of 6·28 MJ per kg DM. The in vitro apparent DM digestibility of Atriplex was approximately 0·09 higher than the in vivo apparent digestibility.The mean nitrogen concentration of the Atriplex DM was 16·6 g/kg, and its apparent digestibility 0·73, which was not improved by the addition of tapioca to the diet. Nitrogen retention of the sheep eating only Atriplex was proportionately 0·17 of the nitrogen intake. The addition of 300 g tapioca improved nitrogen retention to 0·27 but was not significantly different from the other treatments.Water intake and urine excreted were as high as 14 and 12 I/day respectively, for an Atriplex DM intake of about 1300 g/day. During the experiment the sheep only maintained live weight, despite daily intakes of up to 1200 g Atriplex DM and up to 300 g tapioca.

Toxicity induced by poultry litter consumption: effect on measurements reflecting liver function in beef cows

AbstractDuring clinical investigation of a commercial herd it was found that intake of supplemented poultry litter (PL) by beef cows at &gt;10 kg/day, was associated with severe cachexia and a mortality rate of between 10 and 20% of cows. Postmortem analysis of 40 fresh carcasses and elevated serum levels of cholesterol, bilirubin, alkaline phosphatase, glutamic oxaloacetic transaminase and sorbitol dehydrogenase in cachetic cows indicated that the cows suffered severe liver damage. The interrelationship between liver damage and PL intake was subsequently investigated in three groups of 20 beef cows each, consuming 0, 3 and 10 kg PL respectively. As determined by the serum indices, intake of 3 kg PL seemed to be sufficient to cause liver damage, although these cows appeared healthy.In another experiment, six beef cows were stall-fed a diet giving separate access to PL and wheat straw. PL intakes were 3·1,4·7 and 6·0 kg/day. Ruminal ammonia concentration was three to five times higher than the estimate of that required for maximal fermentation in the rumen. The high pH values (6·81 to 6·97) found are optimal for absorption of ammonia from the rumen. The combination of excess absorption of ammonia from the gut and low metabolizable energy intake might have been the cause of liver damage.

The nutritive value of industrial by-products for poultry

The metabolizable energy (ME) and partly also the digestibility of several industrial by-products, mainly originating from grain, were determined in trials with adult cockerels. Five experiments were performed using a conventional total collection procedure, and test ingredients were substituted for 25-40 % of the basal diet. The nitrogen-corrected apparent (AMEn) and true (TMEn) metabolizable energy values of distillers’ dried grains (DDG) and distillers’ dried grains with solubles (DDGS) derived from barley, wheat and rye varied from 7.85 to 11.8 and from 7.98 to 12.0 MJ/ kg DM, respectively. The highest MEn values were observed in the dehulled barley-derived products. The digestibility of crude protein (CP) was 62-83 and that of carbohydrates 25-50 %, the latter being lowest for feeds originating from whole barley grain. The results indicated that distillers’ feeds derived from dehulled grain, especially barley, are satisfactory energy sources for poultry diets. Dried barley protein (BP 1, CP 38 %), oats protein (CP 44 %) and distillers’ solids (CP 58 %) from the integrated ethanol starch process, as well as dehulled barley and oats proved to be excellent energy feeds containing AMEn 14.9, 18.6, 15.0, 14.2 and 14.6 MJ/kg DM, respectively. The TMEn values for BPI and dehulled grains were 15.3, 14.4 and 14.8 MJ/kg DM. Supplementation with enzymes did not significantly improve the ME value of dehulled barley. The AMEn values for barley protein (BP2, CP 27 %), barley bran and barley molasses obtained from the starch process, and wheat feed meal from the milling industry, were 13.3, 8.52, 13.5 and 10.6 MJ/kg DM, respectively. The lowest ME values were obtained for samples of wheat bran, dried potato pulp and malt sprouts: AMEn 6.09, 6.23 and 6.01; TMEn 6.15, 6.07 and 6.01 MJ/kg DM, respectively.

The chemical composition and energy value of high temperature dried grass produced in England

The chemical composition, digestibility in vitro and in vivo and energy value in vivo of 22 high temperature dried, milled and pelleted grasses are reported. Prediction relationships between digestibility and metabolisable energy (ME) content and various laboratory measurements were also examined. The dried grasses were produced on five commercial drying plants throughout England over 4 years. They comprised 13 samples of early season and nine samples of later season material with 18 samples being based on perennial ryegrass and four on tall fescue. For the perennial ryegrass material there was a significant ( P < 0.05) increase in the majority of cell wall fractions in the later compared with the early season samples although total cell wall content (measured as neutral detergent fibre) did not change significantly. Digestibility measured in vitro and in vivo was high but declined significantly ( P < 0.01) between early and later season. Mean organic matter digestibility coefficients in vivo for early and later season were 0.78 and 0.73. Using predicted methane energy losses the mean ME contents were 11.5 MJ kg −1 dry matter (DM) and 10.3 MJ kg −1 DM, respectively. Higher levels of total ash in the later season material significantly contributed to the lower ME contents. The mean measured methane energy loss on a subset of nine samples was 0.061 of gross energy (GE) compared with 0.080 of GE predicted using a published relationship. Four samples of dried grasses based on tall fescue had higher contents of cell wall fractions and lower digestibility and energy values than those based on perennial ryegrass, although small numbers did not allow a statistical assessment of the differences. The mean ME contents of early and later tall fescue material were 9.2 MJ kg −1 DM and 9.4 MJ kg −1 DM using predicted methane energy losses. The best laboratory predictor of digestible organic matter content of the dry matter (DOMD) and ME was the enzymatic procedure based on neutral detergent-cellulase (NCD). The regression relationships were: DOMD (g kg −1 DM) = 59.9 + 0.828 NCD (g kg −1DM), R 2 = 90.4%, RSD = 15.2 ME (MJ kg −1 DM) = −0.59 + 0.0154 NCD (g kg −1 DM), R 2 = 80.6%, RSD = 0.43

Treatment and control of an outbreak of fat cow syndrome in a large dairy herd

An outbreak of fat cow syndrome occurred in a herd of 300 Friesian and Friesian/Holstein dairy cows calving predominantly between January and May. The herd came in off grass in good condition despite a long and hot summer. The dry cows received a diet of grass silage, brewing waste and minerals until the end of December, but the grass silage was butyric and was partially replaced by maize silage. By January 23, 16 of 70 calving cows (23 per cent) had appeared to suffer milk fever. Subsequent blood tests revealed that the cows may have been ketotic, and clinical and post mortem examination showed that they were probably suffering from fat cow syndrome. The freshly calved sick cows were treated with glucose, and corticosteroids were injected every second day into those which remained ill. The cattle had received a high energy diet, but the cows still to calve were placed on a diet of low metabolisable energy (77 MJ/cow) but adequate levels of undegradable protein. The problem was associated with a possible clostridial infection in two cows and with reduced fertility.

Supplementary forage for grazing sheep. 2. Effects on weaned lambs

AbstractIn two experiments weaned entire ram lambs were offered either pasture alone or pasture plus ad libitum conserved forage for 7–12 weeks during the finishing period. Herbage height was maintained at 3·2 cm on both treatments by manipulation of stocking rate in the twenty‐four plots (twelve per treatment) used for the experiment. In experiment 1 silage, which was of lower metabolizable energy (ME) and crude protein (CP) content than the grazed herbage, was consumed at an average of 194 g DM head−1 d−1, providing approximately 40% of total DM intake requirements. In experiment 2 a strawmix, containing (g k g −1 freshweight) 450 g barley straw, 300 g concentrate and 250 g molasses and again with a lower ME and CP content than the grazed herbage, was consumed at an average of 57 g DM head−1 d−1, providing approximately 11% of total DM intake requirements. In both experiments stocking rate was increased by 20–25% by providing forage, but lamb growth rate was not affected.