MJ Metabolizable Energy Research Articles

Heifer nutrition during early- and mid-pregnancy alters fetal growth trajectory and birth weight

Maternal nutrient intake during gestation can alter fetal growth. Whilst this has been studied extensively in the sheep, less is known about effects in the bovine. Composite-breed beef heifers were allocated to either a high (H/− = 76 MJ metabolisable energy (ME) and 1.4 kg crude protein (CP)) or low (L/− = 62 MJ ME and 0.4 kg CP daily) nutritional treatment at artificial insemination. Half of each nutritional group changed to an opposite nutritional group at the end of the first trimester (−/H = 82 MJ ME and 1.4 kg CP; −/L = 62 MJ ME and 0.4 kg CP daily), resulting in 4 treatment groups: HH ( n = 16); HL ( n = 19); LH ( n = 17); LL ( n = 19). During the third trimester all heifers were fed the same diets. Fetuses were measured at 4-weekly intervals beginning at day 39 of gestation. Calves were also measured at birth for physical body variables. Low maternal nutrient intake was associated with decreased crown-rump length at day 39 ( P < 0.01) and increased thoracic diameter at day 95 ( P < 0.01). Umbilical cord diameter was reduced in L/− fetuses in the first trimester ( P < 0.05) but was greater in −/L fetuses in the second trimester compared to their respective H counterparts ( P < 0.05). Calf birth weight was decreased in association with −/L maternal diets ( P < 0.05). In conclusion, fetal development of cattle may be affected by maternal nutrition as early as day 39 of gestation. This may be followed by either compensatory fetal growth, or alternatively, preferential fetal tissue growth that is dependant upon maternal nutrition. Clearly, calf birth weight may be altered by maternal nutrition during mid-gestation.

Opportunities and limitations of food - feed crops for livestock feeding and implications for livestock - water productivity

The paper discusses the contribution of crop residues (CR) to feed resources in the context of the water productivity of CR in livestock feeding, using India as an example. It is argued that crop residues are already the single most important feed resource in many livestock production systems in developing countries and that increasing their contribution to livestock feeding needs to be linked to improving their fodder quality. Using examples from multi-dimensional crop improvement, it is shown that CR fodder quality of key crops such as sorghum, rice and groundnut can be improved by genetic enhancement without detriment to grain and pod yields. Improving crop residue quality through genetic enhancement, agronomic and management interventions and strategic supplementation could improve water productivity of farms and systems considerably. The draw-backs of CR based feeding regimes are also pointed out, namely that they result in only moderate levels of livestock productivity and produce higher greenhouse gas emissions than are observed under feeding regimes that are based on high quality forages and concentrates. It is argued that feed metabolisable energy (ME) content should be used as an important determinant of livestock productivity; water requirement for feed and fodder production should be related to a unit of feed ME rather than feed bulk. The paper also revisits data from the International Water Management Institute (IWMI) work on livestock–water productivity in the Indian state of Gujarat, showing that water input per unit ME can vary several-fold in the same feed depending on where the feed is produced. Thus, the production of one mega joule of ME from alfalfa required 12.9 L of irrigation-derived water in south Gujarat but 50.7 L of irrigation-derived water in north Gujarat. Wheat straw in south Gujarat required 20.9 L of irrigation-derived water for 1 MJ ME and was in this instance less water use efficient than alfalfa. We conclude that water use efficiency across feed and fodder classes (for example crop residue v. planted forages) and within a feed is highly variable. Feeding recommendations should be made according to specific water use requirement per unit ME in a defined production system.

Effects of winter feeding strategies with alternative feeds on the performance of mature suckler cows and their progeny

The present study evaluated the effects of feeding strategies with alternative feeds on the performance of mature suckler cows and their progeny during indoor feeding and subsequent grazing. In both experiments, a 2 × 2 factorially arranged design consisted of two feeding strategies (Step-up, Sas offered on Strategy S, but at a constant daily level. In Experiment 1, cows on Diet C were offered grass silage and straw and on Diet A grass silage and a fl our-mill industry by-product. On Strategy S, feeding was stepped with barley (0, 1.5 and 3.5 kg d-1). On Strategy F, barley was offered 1.43 kg per head daily. In Experiment 2, cows were offered either grass silage (C) or whole-crop barley silage (A) as a sole feed. Strategy S was carried out by offering 68, 95 and 119 MJ metabolizable energy (ME) per cow daily. On Strategy F, roughage was given daily 97 MJ ME. In both experiments, there were no signifi cant differences between treatments in the cow live weight, body condition score, calf pre-weaning live weight gain and cow reproduction. Strategy F can be practised in the nutrition of mature suckler cows in marginal circumstances. Flour-mill industry by-product can partly replace grass silage and straw in the winter diet. Wholecrop barley silage can be offered as a sole feed to suckler cows with good body condition score in autumn.;

Effects of L‐carnitine supplementation to diets with different fat sources and energy levels on fatty acid composition of egg yolk of laying hens

AbstractBACKGROUND: The present study was carried out to determine the effects of feeding diets with two different levels of metabolisable energy (ME) (11.51 or 10.88 MJ ME kg−1 diet) and three different sources of fat (palm oil, sunflower oil or fish oil) with or without supplemental L‐carnitine (0 or 500 mg kg−1 diet) on the fatty acid (FA) composition of egg yolk and the passage of n3 polyunsaturated FAs to egg yolk in laying hens.RESULTS: The ∑n3, particularly C22:6n‐3, FA contents of egg yolk were significantly reduced by adding of L‐carnitine (C2) to different fat sources (P &lt; 0.01). The ratio of n6/n3 was reduced from 53.77 to 17.72 in eggs yolks when ME was lowered in the diet with C2‐sunflower oil (SFO) whereas it was enhanced from 2.19 to 9.31 in C2‐E2 (low energy) diet with fish oil (FO) (P &lt; 0.001). The diet with E2 or C2 containing FO resulted in a decrease of the C22:5n‐3, C22:6n‐3 and ∑n3 FA contents of egg yolk (P &lt; 0.001). On the other hand, supplementation of C2 to diets with SFO or palm oil (PO) caused to a decrease in the C22:6n‐3 and ∑n3 FA contents of egg yolk (P &lt; 0.01). A significant increase of the ratio of n6/n3 in egg yolk can be seen by feeding with E2 diet by adding of C2 to all fat sources like in E1 (normal energy) diet (P &lt; 0.001).CONCLUSION: Dietary treatments resulted in major changes in FA composition of egg yolk. The supplemental C2 in diet decreased the C22:5n‐3, C22:6n‐3 and ∑n3FA contents in egg yolk. The use of FO in diets with E2 significantly reduced the passage rate of C22:6n‐3 FA to egg yolk. Copyright © 2008 Society of Chemical Industry

Effect of herbage on N intake and N excretion of suckler cows

The release of nitrogen on pastures by the grazing animal is a significant source of N load to soil and water and hence a possible source of nitrate pollution. Here we studied the effect of forage quantity and quality related to N intake to examine excretion and loss. A two-year grazing experiment on an intensively managed Lolio-Cynosuretum was established in Rengen Research Station, Germany. Two groups of 4 suckler cows each were grazed along a gradient of forage mass and quality consisting of 16 plots each in 4 replicates per year. Our results show that in the final plots of the gradient, forage mass exceeded by far the recommended optimum of herbage allowance. At the same time, herbage quality decreased along that gradient from about 11 to 9.5 MJ metabolisable energy per kg dry matter, but daily N intake increased from 140 to 600 g N per animal. The related N excretion per animal was constant, with faeces at about 60 to 75 g N. In contrast, daily N excretion with urine increased linearly depending on N intake from less than 100 g to more than 500 g per animal. Thus, N loss was estimated to increase in the same way and was determined as about 22% of total N intake. We conclude that low quality in tall swards, including partly senesced plant material, does not imply low herbage and N intake and N excretion. Our findings indicate that in grassland extensification schemes, where late turning out to pasture is common, N intake and hence excretion might disagree with the intention of limiting forage N conversion and subsequent release to the environment. We also provide a simple spreadsheet with which farmers can quantify the N excretion as a factor of herbage allowance, faeces N content, daily N retention and stocking density. This appears useful not only under standard conditions on improved grassland, but also in environmentally sensitive areas where N release is required to be kept under strict control.

Effect of dietary oils and conjugated linoleic acid on the growth performance of broilers vaccinated with the La Sota Newcastle vaccine

The objective of this study was to investigate the effects of dietary oils on growth performance of broiler chicks vaccinated with La Sota vaccine against Newcastle disease. One hundred and seventy five 1-week old Ross PM3 male broiler chicks were randomly allocated to five dietary groups (n = 35 chicks/group) and fed diets supplemented with 0.5% sunflower oil (Group A), 0.5% olive oil (Group B), 0.5% beef tallow (Group C), 0.5% conjugated linoleic acid (CLA, Group D) or 0.5% hazelnut oil (Group E) for five weeks. Diets contained 230 g crude protein/kg and 12.97 MJ metabolisable energy (ME)/kg (starter diet); 220 g crude protein/kg and 12.97 MJ ME/kg (grower diet) or 200 crude protein/kg and 12.97 MJ ME/kg (finisher diet). The broiler chicks were vaccinated with La Sota Newcastle vaccine at 22 days of age. Body weights were measured weekly and carcass characteristics and some organ (liver, heart, gizzard and intestine) weights were determined after slaughter. The growth rates of broilers from the Groups A, C and E were negatively influenced by vaccination, compared to Group D, which maintained its growth rate. There was no difference in the proportions of abdominal fat (%) of the chickens among the groups. The respective relative organ weights did not differ significantly between the respective dietary treatments. This study showed that the broiler chicks fed a diet supplemented with CLA had significantly better performance and carcass weights compared to the other groups. The present study also indicated that CLA included at a level of 0.5% in the diet prevented weight loss due to vaccination. South African Journal of Animal Science Vol. 37 (2) 2007: pp. 74-80

Programming of intermediate metabolism in young lambs affected by late gestational maternal undernourishment

Effects of moderate maternal undernourishment during late gestation on the intermediary metabolism and maturational changes in young lambs were investigated. 20 twin-bearing sheep, bred to two different rams, were randomly allocated the last 6 wk of gestation to either a NORM diet [barley, protein supplement, and silage ad libitum approximately 15 MJ metabolizable energy (ME)/day] or a LOW diet (50% of ME intake in NORM, offered exclusively as silage approximately 7 MJ ME/day). Post partum, ewes were fed to requirement. After weaning, lambs were fed concentrate and hay ad libitum. At 10 and 19 wk of age, lambs were subjected to an intravenous glucose tolerance test (IGTT) followed by 24 h of fasting. Heat energy (HE) was determined in a respiration chamber at 9 or 20 wk of age. LOW lambs had a lower birth weight and continued to be lighter throughout the experiment. Glucose tolerance did not differ between groups. However, 19-wk-old LOW lambs secreted less insulin during IGTT, released more NEFA, and tended to have lower leptin during fasting than NORM. Surprisingly, several metabolite and hormone responses during IGTT and fasting were greatly influenced by the paternal heritage. In conclusion, when lambs entered adolescence (19 wk) programming effects of late prenatal malnutrition on the glucose-insulin homeostasis and metabolism were manifested: LOW lambs had less insulin-secretory capacity, but this was apparently compensated for by increased target tissue sensitivity for insulin, and adipose lipolytic capacity increased during fasting. Thereby, glucose may be spared through increased lipid oxidation, but overall energetic efficiency is apparently deteriorated rather than improved.

Optimising dietary energy and amino acid levels in the diets of naked neck broilers for growth, nutrient utilisation and immune response in a hot climate

AbstractThe need for a critical amino acid (AA) profile for growth, immune response and N utilisation of naked neck broilers during summer was studied. Day‐old naked neck chicks (n = 198) from a single hatch were distributed into 24 groups (four dietary regimens (DRs) with six replicates each) having eight birds in each replicate. The first diet was based on crude protein (CP) and metabolisable energy (ME) (13.40 MJ) as per NRC recommendations (DR1). In the second diet, the CP content was reduced through supplementation of synthetic AAs to achieve critical AA contents as suggested by NRC with 13.40 MJ ME (DR2). In the third diet critical AAs were supplemented to achieve their level at 108% of NRC with 12.6 MJ ME (DR3), while in fourth diet critical AA concentration was reduced to 94% (DR4) of NRC with 12.6 MJ ME to match the ratio of ME to AA concentration as that of NRC (1994). Diets were formulated separately for starter (0–3 weeks) and finisher (3‐6 weeks) phases. A metabolism trial was conducted at the third week of age. At 3 and 6 weeks of age eight birds (four of each sex) per treatment were killed to study the growth of immune organs (Bursa of Fabricius, thymus and spleen). Immune response was studied at the fourth week of age. During the starting phase, the birds fed DR1 and DR2 having 13.40 MJ ME kg−1 diet had higher body weight (P &lt; 0.044) gain (P &lt; 0.048) and better feed conversion ratio (FCR) (P &lt; 0.001) as compared to DR3 and DR4 (12.6 MJ ME kg−1 diets). However, better (P &lt; 0.001) CP efficiency (CP intake kg−1 gain) and lower feed cost kg−1 gain (P &lt; 0.001) was recorded in DR4. A similar trend was also observed during the finisher phase. Dietary regimens had no effect on dry matter (DM) metabolisability, N intake or output and N retention. There was no difference in the weight of immune organs (bursa, thymus and spleen) between dietary treatments at either 3 or 6 weeks of age. The cell mediated and humoral immune response was also not different between the NRC and modified NRC levels. Copyright © 2007 Society of Chemical Industry

Effects of the dietary protein content and the feeding level on protein and energy metabolism in Iberian pigs growing from 50 to 100 kg body weight

Nutritional requirements of the Iberian pig, a slow-growing, obese porcine breed, are not well defined and seem to differ from those of conventional or high-performing pigs. The effects of the dietary protein content and the feeding level on the utilisation of metabolisable energy (ME) and the rates of gain, protein, and fat deposition were studied with 81 Iberian castrates growing from 50 to 100 kg body weight (BW) by using the comparative slaughter technique. The animals were fed 4 diets providing 145, 120, 95, and 70 g ideal crude protein (CP) per kg dry matter (DM), and containing 13.94, 14.29, 14.56, and 14.83 MJ ME per kg DM, respectively. Three levels of feeding were evaluated: 0.60, 0.80, and 0.95 × ad libitum intake. Growth rate increased (linear and quadratic, P < 0.001) as the dietary ideal CP content decreased. It also increased with the feeding level (linear, P < 0.001; quadratic, P < 0.05). Gain:feed and gain:ME intake improved by decreasing the ideal CP content in the diet (linear, P < 0.001 and P < 0.05, respectively; quadratic P < 0.001 for both variables). Increasing the feeding level improved linearly gain:feed and gain:ME intake ( P < 0.001). Protein deposition (PD):ME intake ranged between 1.23 and 1.44 g/MJ, and it showed a tendency to reach the maximum value when the diet providing 95 g ideal CP per kg DM was fed (quadratic, P = 0.078). When this diet was offered at 0.95 × ad libitum, PD reached a maximum value of 71 g/day. This dietary treatment resulted in average values for average daily gain and retained energy (RE) of 854 g/day and 21.4 MJ/day, respectively. The average rate of gain was 19.93 g/MJ increase in ME intake, equivalent to an energy cost of 50.2 kJ ME per g gain, irrespective of the dietary ideal CP content. Also, the overall marginal efficiency of protein deposition (ΔPD:ΔME; g/MJ) was 1.34. Increasing the feeding level led to increases in PD (linear, P < 0.001) and RE (linear, P < 0.001; quadratic, P < 0.01) irrespective of the dietary ideal CP concentrations. Between 50 and 100 kg BW, the chemical composition of 1 kg gain averaged 78, 592, 28.7, and 284 g for CP, fat, ash, and water respectively. The net efficiency of use of ME for growth ( kg) and the maintenance energy requirements were 0.606 and 396 kJ/kg BW 0.75 per day, respectively. The results support earlier findings that the genotype has marked effects on protein and energy metabolism of growing pigs and underline important compositional differences of the Iberian pig compared with conventional or modern porcine genotypes.

Effects of plane of nutrition during the first month of pregnancy on conception rate, foetal development and lamb output of mature and adolescent ewes

AbstractEmbryo transfer studies have demonstrated that high plane feeding in early pregnancy is detrimental to the successful establishment of pregnancy in adolescent but not mature ewes. To further examine this relationship with ewes that conceive naturally and to investigate its effects on foetal development, 102 Greyface and Texel×Greyface ewes (body condition score (BCS) 3·8) and 114 Texel×Greyface adolescent ewes (BCS 3·3) were allocated to one of three treatments following a synchronized mating. From day 1 to 31 of pregnancy, animals were offered grass nuts (10·2 MJ metabolizable energy (ME) per kg dry matter (DM); 163 g crude protein per kg DM) at one of three levels to supply approximately 2·0 (H); 1·0 (M) and 0·6 (L) of their predicted ME requirements for maintenance. Increasing the post-mating plane of nutrition resulted in significant increases in ewe live weight (P&lt;0·001) and BCS (P&lt;0·001) during the treatment period. When diets were standardized for all animals during mid pregnancy (days 31 to 105), L ewes gained more live weight (P&lt;0·05) and BCS (P&lt;0·001) than H ewes. Early pregnancy nutrition had no effect on the conception rate of mature ewes; however adolescent ewes on the H and M treatments had lower conception rates (P&lt;0·05) than those offered the L diet (0·59, 0·61 and 0·82 respectively). As a result, L adolescent ewes tended to have a higher mean total lamb birth weight per ewe mated (P=0·09) although lamb output at weaning was not influenced by plane of nutrition. Lambs born from adolescent mothers had lower lamb birth weights (P&lt;0·001) and a shorter mean head length, crown-rump length and thoracic girth (P&lt;0·001). Foetuses from H ewes had longer hind legs than those from L ewes on day 83 of gestation (P&lt;0·05) and at term (P&lt;0·05). The results of this study suggest that allowing adolescent but not mature ewes to lose live weight and body condition can increase the proportion of productive ewes following a natural service.

Influence of energy intake on protein and lipid deposition in Creole and Large White growing pigs in a humid tropical climate

AbstractTwenty-four castrated males were used to study the effect of breed (Large Whitev. Creole (LWv. CR)) and feeding level (0·70, 0·80, 0·90, and 1·00 ad libitum) on growth performance and protein deposition (PD) and lipid deposition (LD) between 30 and 60 kg in growing pigs under tropical climatic conditions; the CR pigs are raised in the Caribbean area and can be qualified as fat and slow growing pigs. Daily protein and amino acids supplies were calculated to be non-limiting for protein gain. Total PD and LD were measured according to the comparative slaughter technique. Digestibility coefficients of energy and nutrients were estimated over a 10-day period at 45 kg live weight. Neither the breed nor the feeding level influenced the apparent digestibility coefficients of dietary nutrients; only energy digestibility was increased at reduced feeding levels (P&lt;0·05). Average daily gain increased linearly with the increase of metabolizable energy (ME) intake and the slope of the relationship was lower in CR than in LW pigs (30·4v. 36·6 g per additional MJ ME). The food conversion ratio was not affected by feeding level but it was significantly higher in CR than in LW pigs (2·88v. 2·36 kg /kg;P&lt;0·001). Daily PD increased with ME intake according to a linear relationship in both breeds and the slope was significantly affected by breed (3·1v. 4·2 g/MJ ME in CR and LW pigs, respectively;P&lt;0·001). In contrast, the increase of LD and total energy retained with ME were higher in CR than in LW pigs (8·4v. 6·4 g/MJ and 0·40v. 0·36 MJ/ MJ ME, respectively;P&lt;0·001).

Effects of feeding fat‐coated butyrate on mucosal morphology and function in the small intestine of the pig

As shown earlier, pig rations with high starch and purine content initiate mucosal hypertrophy by stimulating mitotic activity and DNA formation in the small intestine, whereas in the colon butyrate inhibits apoptosis and thus increases crypt depth. It was the aim of this study to combine these effects by targeting fat-coated butyrate into the small intestine where it usually does not occur, and to investigate effects on mucosal development and function. Three groups of five pigs were fed 3.6 kg/day of either a low-energy ration [deficit group, 6.6 MJ metabolizable energy (ME)/kg] or a high-energy ration (13.7 MJ ME/kg) that was supplemented with brewing yeast as a source of purines. The third ration was of high energy and contained purines and was additionally supplemented with coated butyrate (13.5 MJ ME/kg; 29 g calcium butyrate/kg). Rations were fed for 5 days. After killing, tissue samples were obtained from the proximal, medial and distal parts of jejunum for histology. Chyme samples were obtained from the ileum of all animals and used for sucrase determination. Villus size was not changed by feeding, but butyrate had an effect on plica height and area mainly in the medial jejunum. Plica area in the butyrate group (4.2 mm(2)) was significantly higher (p <or= 0.01) compared with that of the deficit group (2.3 mm(2)) and high-energy group (2.7 mm(2); p <or= 0.01). For the butyrate group, sucrase activity in the ileum was 119.1 U/ml and thus significantly higher (0.05) compared with the high-energy group (61.7 U/ml) and the deficit group (28.0 U/ml; p <or= 0.001). Targeting butyrate into the small intestine thus improves digestive and absorptive capacities. The mechanism probably is a specific effect on enterocyte mitosis which in turn leads to an increased plica size by crypt fission.

Insulated, uninsulated and outdoor housing for replacement beef heifers on restricted grass silage-based diet in a cold environment

Abstract The present experiment studied whether replacement beef heifers, offered restricted amounts of a grass silage-based diet, can be overwintered in outdoor housing facilities in cold Nordic conditions (minimum temperature approximately − 35 °C). Twenty-one Hereford heifers, initial live weight (LW) 237 kg in Experiment 1 and 256 kg in Experiment 2, were selected for a two-year study. In both experiments, the treatments consisted of three winter housings which were Insulated pen (I), Uninsulated pen (U) and Outdoor area with a rain shelter (O). Grass silage supplemented with oats was offered restricted and the heifers received daily during winter on average 63 and 65 MJ metabolizable energy in Experiment 1 and 2, respectively. The live weight gain of the heifers in treatment U (795 g/d) was higher than in the other treatments (I; 760 and O; 747 g/d). No significant differences in the body condition score (scale from extremely thin, 0 to extremely fat, 5) were observed between the treatments. In Experiment 1, the serum concentrations of long-chain fatty acids were lower in the heifers in treatment I than in the heifers in the other treatments, probably due to increased lipolysis of the heifers in treatment I. In both experiments the serum concentrations of urea were lower and concentrations of total proteins higher in the animals in treatment I than in the other animals. No clear harmful effects, like muscle injuries, extraordinary stress or increased occurrence of diseases, could be observed in any of the treatments. The breeding season was 78 and 83 days in Experiment 1 and 2, respectively. The conception rate after natural breeding was 95% in both experiments. On the basis of the results, replacement beef heifers on a restricted feeding scheme can be overwintered outdoors in Nordic conditions without negative effects on animal performance. Nevertheless, the outdoor winter housing facilities must protect the animals from becoming wet and dirty and thus should be equipped with a rain shelter to provide a dry resting area with sufficient bedding material available.

Responses to supplementation by dairy cows given low pasture allowances in different seasons 1. Pasture intake and substitution

AbstractTwo factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or supplemented with 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. Two different supplements were offered, namely, rolled maize grain (MG) and a mixture of foods (BR) formulated to nutritionally balance the diet. In experiment 2, a fourth treatment consisting solely of a generous pasture allowance (60 to 75 kg DM per cow per day, AP) was introduced. Offering MG and BR increased DM intake (DMI). At the restricted pasture allowance, increasing total ME allowance (MEA) by offering supplementary foods increased ME intake (MEI) by 0·68 (s.e. 0·047) MJ per extra MJ ME offered. This highly significant (P&lt;0·001) linear relationship was consistent across seasons, and did not diminish at higher MEA. In experiment 2, cows in early lactation had lower substitution rates than mid and late lactation cows irrespective of season. Substitution rate was higher when higher pasture allowance or quality of pasture on offer enabled the unsupplemented cows to achieve higher DMI from pasture than at other times of the year. These results suggest that one of the key factors determining the intake response to supplementary foods is pasture allowance. Within spring calving dairying systems, the largest increases in total DMI per kg of supplement offered is likely when offering supplements to early lactation cows grazing restricted allowances of high quality pasture.

Responses to supplementation by dairy cows given low pasture allowances in different seasons 2. Milk production

AbstractTwo factorial experiments were designed to determine the effects of stage of lactation, and season of the year, on cow responses to supplementary feeding. These experiments were conducted over consecutive years with 128 high genetic merit multiparous Holstein-Friesian cows in early, mid and late lactation in spring, summer, autumn and winter. At each stage of lactation, and in each season of the year, cows were offered a restricted pasture allowance (25 to 35 kg dry matter (DM) per cow per day), either unsupplemented (control) or with supplement at 50 MJ metabolizable energy (ME) per cow per day in experiment 1 and 80 MJ ME per cow per day in experiment 2. The two supplements given in both years were rolled maize grain (MG) and a mixture of foods formulated to nutritionally balance the diet (BR). In experiment 2, another treatment, of a generous pasture allowance (60 to 75 kg DM per cow per day) (AP), was imposed on an additional group of early lactation cows during each season. Direct milk solids (MS) (milk fat plus milk protein) responses in experiment 1 to MG were 169, 279, 195 and 251 g MS per cow per day in spring, summer, autumn and winter, respectively, while those to BR were 107, 250, 192, 289 g MS per cow per day. In experiment 2, however, milk solids responses to both supplements during spring were slightly below the control treatment, with values similar to those in experiment 1 in summer and autumn for cows on the BR but not the MG supplement. Milk solids responses to supplementary foods were largest during seasons of the year when the quantity and quality of pasture on offer resulted in the lowest milk solids yield from unsupplemented cows. When carry-over effects of feeding MG and BR on milk solids production were detected, they were only about half the magnitude of the direct effects. Serum urea concentrations were higher in control cows than those offered MG with a similar effect for BR in all but summer in experiment 1, while serum glucose concentrations were highest in winter and lowest in summer. The most important factor influencing milk solids responses was the relative food deficit (RFD) represented by the decline in milk solids yield of the respective control groups after changing from a generous pasture allowance to restricted allowance when the feeding treatments were imposed. Total milk solids responses (direct and carry-over) to supplements were greatest when severe food restrictions, relative to the cows' current food demand, resulted in large reductions in milk solids yield of the control groups. The RFD was the best predictor of milk solids response to supplementary foods. Therefore, it is likely that cows are most responsive to supplementary foods during or immediately after the imposition of a severe food restriction.

The impact of controlled nutrition during the dry period on dairy cow health, fertility and performance

Average dairy herd fertility is declining, with more serves per successful conception, extended calving intervals and increased culling due to failure to rebreed, all adding significant costs to milk production. Genetics, management and nutrition have all contributed to this decline in fertility; the paper focuses primarily on nutritional issues. The extent of body condition loss after calving and its possible impact on fertility is considered, with evidence that this phenomenon is common in many herds irrespective of average milk yields. Body tissue mobilisation after calving increases the flux of non-esterified fatty acids to the liver and pathways of fatty acid metabolism are considered. Particular attention is given to the effects of high plasma non-esterified fatty acid levels on fat accumulation in liver cells and possible impacts on nitrogen and glucose metabolism. Current nutritional practices with early lactation cows which aim to stimulate milk yield and peak milk production but have been shown to exacerbate body condition loss, are reviewed. The paper also considers cow health issues during the peri-parturient period and how these may affect milk yield and fertility. It is concluded that current feeding practices for dry cows, with the provision of increasing amounts of the lactation ration during the Close-up period to accustom the rumen microbes and offset the expected reduction in feed intake as pregnancy reaches term, have largely failed to overcome peri-parturient health problems, excessive body condition loss after calving or declining fertility. From an examination of the energy and protein requirements of dry cows, it is suggested that current Close-up feeding practices can lead to luxury intakes of nutrients that can increase fat deposition in the viscera and the liver. Under such conditions, metabolism of nutrients by the cow may be compromised. In contrast, limited feeding throughout the whole dry period has been shown to prevent many of the problems which can affect peri-parturient cows. A new feeding strategy based on a low energy: high fibre ration (9 MJ metabolisable energy and 130 g crude protein/kg ration dry matter) containing high levels of chopped straw and offered ad libitum as a total mixed ration throughout the whole dry period is proposed. The performance of 32 dairy farms in France where this strategy has been adopted for at least 3 years is provided, with positive outcomes now being obtained by UK and Irish dairy farmers. Independent US research evidence has confirmed some of these benefits whilst limited data on cow fertility is presented. It is hypothesised that luxury feeding during the dry period can cause cows to become insulin resistant leading to an increased risk of type II diabetes. Such cows are likely to have poorer fertility whilst possible mechanisms which increase the risk of peri-parturient health problems are discussed. Further research to understand the mechanisms of these effects is required and is currently ongoing. However the magnitude of the effects noted on an increasing number of dairy farms suggests this approach to feeding the dry cow is capable of bringing real benefits to many dairy herds in terms of fewer health problems, reduced body condition loss and improved fertility.

Effects of dietary protein content and feeding level on carcass characteristics and organ weights of Iberian pigs growing between 50 and 100 kg live weight

AbstractThe effects of dietary protein content and level of feeding on carcass characteristics and organ weights were studied in castrated male Iberian pigs growing from 50 to 100 kg live weight (LW). Animals were offered four diets providing 145, 120, 95 and 70 g ideal crude protein (CP) per kg dry matter (DM) and 13·94, 14·29, 14·56 and 14·83 MJ metabolizable energy (ME) per kg DM, respectively. Three levels of feeding were assayed: 0·60, 0·80 and 0·95 of ad libitum intake. The pigs were slaughtered at 100 kg LW. Daily gain in carcass (carcass gain, g/day) and protein deposition (PD, g/day) in this component attained 76·2% and 78·8% of whole-body average daily gain and PD, respectively. Carcass gain improved with each decrease in dietary CP from 145 up to 120 g/kg DM and then levelled off. A small but significant effect of dietary CP on carcass composition was observed, due to an enhanced fat deposition in pigs fed the lowest protein content diet. Mean values of protein, fat, ash and water contents in the carcass were 101·8, 522·7, 27·6 and 353·7 g/kg respectively. PD in the eviscerated carcass was not affected significantly by dietary protein level but tended to reach a maximum value with the diet that provided 95 g CP per kg DM: 55·7 g/day at the highest feeding level assayed. Carcass energy retention (MJ/day) increased significantly (P&lt;0·001) with decreasing dietary protein supply and on increasing level of feeding. Raising feed intake resulted in a significant decrease for carcass and a concomitant increase for viscera, as proportions of empty body weight (P&lt;0·05 andP&lt;0·001, respectively). Proportional weights of shoulder and ham were not affected either by dietary CP content or feeding level. Proportionate weights of dissectable fat in the shoulder and intermuscular and subcutaneous fat in the ham were not affected by CP content of the diet. In contrast, intermuscular fat content of ham was increased by feeding level (P&lt;0·05), likely with implications for the quality of the cured meat product.

Response of growing Japanese quails to dietary concentration of L‐threonine

AbstractThe influence of dietary levels of L‐threonine (Thr) on growth and immune response was investigated in growing (0–5 weeks of age) Japanese quails (n = 288). Three dietary treatments were formulated using three levels of Thr [9.6, 10.2 and 11.2 kg−1 diet dry matter (DM)] at a fixed protein level of 233 g kg−1 and an energy level of 12.15 MJ (2900 kcal) metabolizable energy (ME) kg−1 feed dry matter. A metabolism trial with a 3‐day collection period was conducted at the third week of age employing all the birds. The cell‐mediated (using PHA‐P) and humoral (SRBC response) immune responses were measured at the fourth week of age. Carcass traits were assessed at the end of fifth week of age. Body weight gain was lower (P &lt; 0.01) in birds received 9.6 g Thr kg−1 DM than in groups fed 10.2 g or 11.2 g kg−1 DM in the diet, but there was no significant difference in gain between the groups fed 10.2 or 11.2 g Thr kg−1 DM in the diet. Feed intake differed significantly owing to Thr levels being lowest (P &lt; 0.05) at 9.6 g Thr kg−1 DM in the diet. Feed conversion ratio (FCR), protein efficiency and energy efficiency improved at the 11.2 g kg−1 level from 0 to 3 weeks of age; however, from 3 to 5 weeks of age, better FCR emanated from a diet with 9.6 g Thr kg−1 DM. The nitrogen balance did not differ (P &gt; 0.05) with Thr level. Carcass traits, relative weight of immune organs and cell‐mediated (PHA‐P) and humoral (SRBC response) immune responses did not differ significantly (P &gt; 0.05) as a result of the dietary treatments. Copyright © 2006 Society of Chemical Industry

Feeding an energy supplement with white clover silage improves rumen fermentation, metabolisable protein utilisation, and milk production in dairy cows

Six rumen-fistulated Holstein-Friesian cows were used in a Latin square design to test the hypothesis that more frequent feeding of a high energy supplement to cows consuming high-protein white clover silage would improve microbial protein production, resulting in greater N retention and higher milk yields. The white clover silage (10.7 MJ metabolisable energy (ME)/kg DM) was fed to cows either alone (WCS) or with 4.5 kg DM of rolled barley grain (12.1 MJ ME/kg DM). The grain was offered either 24 times (WCS/24B) or twice daily (WCS/2B, at 0800 and 1700 hours). Cows offered the supplements, regardless of feeding frequency, had higher (P &lt; 0.05) organic matter (17.3 v. 16.0 kg/day) and estimated ME (208 v. 189 MJ/day) intakes than cows offered white clover silage alone. Mean daily ruminal fluid pH (P &lt; 0.05) and ammonia-N concentrations (P &lt; 0.05) were lower in the supplemented treatments, with total VFA concentrations being highest (P &lt; 0.05) in the WCS/2B treatment. Nitrogen intake and output in the faeces were similar for all 3 treatments. However, nitrogen excretion was lower (P &lt; 0.05) in urine (174 v. 218 g/day) and higher (P &lt; 0.05) in milk (115 v. 93 g/day) of cows offered the supplements. The crude protein consumed by cows on all 3 diets was estimated to be well in excess of cow requirements. The supplements reduced the calculated net losses of ammonia-N from the rumen from 25% of total crude protein intake for WCS to 14% in the 2 supplement treatments, and increased the metabolisable protein supply available for milk production. Increases in metabolisable protein were estimated to be due to a higher microbial crude protein contribution in the supplemented treatments compared with the WCS treatment. Grain supplements increased (P &lt; 0.05) milk yield (22.4 v.19.6 kg/day) and although there were no significant differences in milk fat and protein concentrations between treatments, the latter tended to increase with grain supplementation. Milk yield was higher in the WCS/24B treatment than in the WCS/2B treatment, but neither the calculated nor the measured rumen variables were sufficiently different to explain this effect of frequency of feeding the grain. One possible explanation for the difference was the marked fluctuations in key rumen variables throughout the day in the WCS/2B compared with the WCS/24B treatment. Such fluctuations in the rumen environment are not accounted for in theoretical calculations since associative effects are not considered. The benefits of a higher milk production as a result of more frequent feeding of the supplement to cows should be considered in context of the additional effort or costs associated with more frequent feeding.

Energy supply of the okapi in captivity: intake and digestion trials

In the nutrition of browsing ruminants in captivity, adequate nutrient digestibility and energy content of diet is debated. Problems related to energy-provision and low forage intake have been reported for the okapi and other browsers like the giraffe, particularly during winter. High-fiber concentrates like unmolassed beet pulp have some potential to improve the nutritional management of these species. Using a total of six okapis in captivity, seven feeding trials were carried out at two facilities (A+B) on a structured but opportunistic base. Three trials (A1, A2, B1) were conducted when animals were fed their regular diet including grain based energy concentrates, fruits and vegetables, and alfalfa (Medicago sativa) hay. Two trials (A5, B2) examined the effect of unmolassed beet pulp, and two (A3,4) examined the effect of unmolassed beet pulp+fresh browse. Daily intake and feces production were quantified over 8–12 days. Samples were analyzed for dry matter, crude ash, neutral detergent fiber (NDF)/acid detergent fiber (ADF)/acid detergent lignin (ADL), crude protein, and gross energy. Metabolizable energy content of diets was estimated via a factor (0.83) from digestible energy. The proportion of beet pulp in diets was 13% (A3), 24% (A4), 20% (A5), and 21% (B2). Browse proportion was 11% (A3) and 32% (A4). Daily feed intake ranged between 1.5–1.7% of body weight (BW), digestibility of organic matter between 61–74%. Digestibility of fiber (NDF) was higher in beet pulp diets (A3=39%, A4=60%, A5=54%, B2=61%) than in the others (A1=48%, A2=33%, B1=48%). Supply of metabolizable energy (ME) ranged between 0.50–0.70 MJ ME/(kg BW0.75*day), meeting energy requirements of okapis of 0.50–0.53 MJ ME/(kg BW0.75*day) in general. Diets with beet pulp+browse were not found to be highest, but in the upper level of the range of forage proportions of this study. Palatable browse species were preferred over all other feedstuff offered. The use of unmolassed beet pulp as energy-concentrate for browsing ruminants like the okapi can be recommended because diets high in this high-fibre feedstuff resulted in adequate energy intakes. Zoo Biol 0:1–14, 2006. © 2006 Wiley-Liss, Inc.