Lowering the dietary protein content can reduce N excretions and NH3 emissions from manure and increase milk N efficiency of dairy cows. However, milk yield (MY) and composition can be compromised ...due to AA deficiency. Methionine and Lys are known as first limiting EAA for dairy cows, and recently His is also mentioned as limiting, especially in grass-based or low-protein diets. To examine this, a trial was conducted with a 3-wk pre-experimental adaptation period (diet 16.5% crude protein), followed by a depletion period of 4 wk, in which 39 cows (average ± standard deviation: 116 ± 29.3 d in milk, 1.8 ± 1.2 lactations, 638 ± 73.2 kg of body weight, and 32.7 ± 5.75 kg MY/d) received a low-protein diet (CTRL) (14.5% crude protein). Then, taking into account parity, His plasma concentration, and MY, cows were randomly assigned to 1 of 3 treatment groups during the rumen-protected (RP) AA period of 7 wk; (1) CTRL; (2) CTRL + RP-Met + RP-Lys (MetLys); (3) CTRL + RP-Met + RP-Lys + RP-His (MetLysHis). Products were dosed, assuming requirements for digestible (d) Met, dLys, and dHis being, respectively, 2.4%, 7.0%, and 2.4% of intestinal digestible protein. In the cross-back period of 5 wk, all cows received the CTRL diet. During the last week of each period, a N balance was conducted by collecting total urine and spot samples of feces. Total feces production was calculated using the inert marker TiO2. Statistical analysis was performed with a linear mixed model with cow as random effect and data of the last week of the pre-experimental period used as covariate for the animal performance variables. No effect of supplementing RP-Met and RP-Lys nor RP-Met, RP-Lys, and RP-His on feed intake, milk performance, or milk N efficiency was observed. However, the plasma AA profile indicated additional supply of dMet, dLys, and dHis. Nevertheless, evaluation of the AA uptake relative to the cow's requirements showed that most EAA (exclusive Arg and Thr) were limiting over the whole experiment. Only dHis was sufficiently supplemented during the RP-AA period due to an overestimation of the diet's dMet and dLys supply in the beginning of the trial. The numerically increased milk urea N and urinary N excretion when RP-Met, RP-Lys, and RP-His were added to the low-protein diet suggest an increased catabolism of the excess His.
During growth, pigs convert plant protein into animal protein. The major part of the ingested protein is excreted via manure, with potential nitrogen (N) losses to the environment. To limit N losses ...and increase sustainability of pork production, the efficiency of protein conversion should be maximized. The aim of this paper is to critically evaluate diet and management strategies linked with N efficiency. Besides nutrition, we discuss three management strategies observed in science and in practice to be linked with improved N efficiency: genetic selection, castration and slaughter weight. Because diet has a marked effect on eventual N losses, it must also be taken into account when evaluating management strategies. A reductionist approach, such as feeding the same diet across all management treatments, may overestimate the effect of a management strategy and eventually lead to incorrect conclusions. The amount of excreted N depends on the amount of ingested N, the amount of absorbed N, the amino acid (AA) balance in the diet and the animal's N and AA requirements. Daily multiphase feeding adapted to the individual animal's AA needs is likely to be the most N efficient. For animals housed in groups, phase feeding is necessary. When combined with periods of temporary AA restriction, N efficiency can be further improved. Specific AA consumption must be balanced by applying the ideal protein concept. With better knowledge of the requirements of individual animals and the commercial availability of certain AAs, the total dietary CP level can be lowered within limits. Further research is needed on the minimal CP level that allows maximal performance. For this end a useful parameter may be the ratio of standardized ileal digestible (SID) lysine : apparent total tract digestible CP level. By combining optimal nutrition and management, a whole body N efficiency approaching 60% may be achievable in the near future.
summary One hundred and seventy‐two fixed reconstructions (317 prosthetic units), made on 283 ITI implants in 105 patients (age range 25–86 years) with a minimum follow‐up period of 40 months, were ...taken into the study to analyse technical complication rate, complication type and costs for repair. The mean evaluation time was 62·5 ± 25·3 months. Eighty were single crowns and 92 different types of fixed partial dentures (FPDs). In 45 cases the construction was screw retained and in 127 cases cemented with zinc phosphate cement or an acrylic‐based cement. Complications occurred after a minimum period of 2 months and a maximum period of 100 months (mean: 35·9 ± 21·4 months). Fifty‐five prosthetic interventions were needed on 44 constructions (25%) of which 88% in the molar/premolar region. The lowest percentage of complications occurred in single crowns (25%), the highest in 3–4 unit FPDs (35%) and in FPDs with an extension (44%). Of the necessary clinical repair, 36% was recementing and 38% tightening the screws. Of all interventions, 14% were classified as minor (no treatment or <10 min chair time), 70% as moderate (>10 min but <60 min chair time) and 14% as major interventions (>60 min and additional costs for replacement of parts and/or laboratory). For seven patients the additional costs ranged from €28 to €840. Bruxing seemed to play a significant role in the frequency of complications. Longer constructions seemed to be more prone to complications. The relatively high occurrence of technical complications should be discussed with the patient before the start of the treatment.
The chemical composition and the energy and protein value of five batches of condensed distillers solubles (CDS) originating from wheat were determined. The net energy for lactation (NEL) was derived ...from digestion coefficients obtained with sheep. The true protein digested in the small intestine (DVE) and the rumen degradable protein balance (OEB) were based on the rumen degradation rate (kdD), the rumen undegradable fraction (U) and intestinal digestibility of undegraded protein (%DVBE) predicted by regression equations derived from a data set of 28 protein feeds with kdD, U and %DVBE determined in situ. The CDS is a by-product with a high, but very variable CP content (238 to 495 g/kg DM). The CP contained on average 81% amino acids, with glutamine as main component (on average 21.8% of CP) and a relatively good lysine proportion (3.0%). Further, CDS contains quite a lot of crude fat (mean±SD: 71±14 g/kg DM), glycerol (95±52 g/kg DM) and sugars (123±24 g/kg DM) resulting in a high organic matter digestibility (88.6±3.0%) and high NEL content (8.3±0.4 MJ/kg DM). The protein value showed a large variation, with DVE ranging from 122 to 244 g/kg DM and OEB from 50 to 204 g/kg DM. Wheat CDS is a rich source of minerals and trace elements with exception of calcium.
The chemical composition inclusive amino acids (AAs) and the energy and protein value of three wheat, three maize and seven blend (mainly wheat) dried distillers grains and solubles (DDGS) were ...determined. The net energy for lactation (NEL) was derived from digestion coefficients obtained with sheep. The digestible protein in the intestines (DVE) and the degraded protein balance (OEB) were determined by nylon bag incubations in the rumen and the intestines of cannulated cows. Additional chemical parameters like acid-detergent insoluble CP (ADICP), protein solubility in water, in borate-phosphate buffer and in pepsin-HCl, in vitro digestibility (cellulase, protease, rumen fluid) and colour scores (L*, a*, b*) were evaluated as potential predictors of the energy and protein value. Compared to wheat DDGS (WDDGS), maize DDGS (MDDGS) had a higher NEL-value (8.49 v. 7.38 MJ/kg DM), a higher DVE-content (216 v. 198 g/kg DM) and a lower OEB-value (14 v. 66 g/kg DM). The higher energy value of MDDGS was mainly due to the higher crude fat (CFA) content (145 v. 76 g/kg DM) and also to better digestible cell-walls, whereas the higher protein value was mainly due to the higher percentage of rumen bypass protein (RBP: 69.8 v. 55.6%). The NEL-value of blend DDGS (BDDGS) was in between that of the pure DDGS-types, whereas its DVE-value was similar to MDDGS. Although lower in CP and total AAs, MDDGS provided a similar amount of essential AAs as the other DDGS-types. Lysine content was most reduced in the production of WDDGS and cysteine in MDDGS. Fat content explained 68.6% of the variation in NEL, with hemicellulose and crude ash as extra explaining variables. The best predictor for RBP as well as for OEB was the protein solubility in pepsin-HCl (R²=77.3% and 83.5%). Intestinal digestibility of RBP could best be predicted by ADF (R³=73.6%) and the combination of CFA and NDF could explain 60.2% of the variation in the content of absorbable microbial protein. The availability of AAs could accurately be predicted from the rumen bypass and intestinal digestibility of CP.
Incremental levels of the phytase, OptiPhos® Plus, were fed to 150 weaned piglets (five treatments of 30 pigs) to determine the effect on piglet performance, nutrient digestibility and bone ...mineralisation. Piglets were fed a basal diet from four to six weeks and a pre-starter diet from six to ten weeks of age. The basal diets contained reduced digestible phosphorus (P) and calcium (Ca) (1.5 g/kg digestible P, and Ca 5.5 g/kg and 5.6 g/kg for weaner and pre-starter, respectively) to provide a negative control. Phytase was added at 0, 125, 250, 500 and 1000 phytase units (FTU)/kg feed. Faecal samples were collected at nine weeks of age and analysed for P, Ca and crude protein (CP) content to calculated digestibility. Metacarpal bone IV mineralisation was assessed by ash content and the weight and length of the bone. Incremental increases of phytase improved final body weight (BW) (P<0.001), average daily gain (ADG) (P<0.001) and feed conversion ratio (FCR) (P<0.01). The statistical model predicted a linear increase for daily feed intake (DFI), ADG and BW with increased phytase increments. BW at the end of the trial increased by 824 g per increase of 250 FTU/kg (P<0.001). ADG and DFI increased by 19 g/day (P<0.001) and 18 g/day (P<0.05) respectively, per increase of 250 FTU/kg. As the effect on ADG and final BW was higher at lowest doses, a quadratic effect for these parameters was observed, within the measured range of phytase levels (P=0.029 and 0.028, respectively). A reduction of 0.03 in FCR was observed for each 250 FTU/kg increase (P<0.01). For each increase in 250 FTU/kg, bone dry weight increased by 131 g (P<0.05) and bone ash concentration by 1.9% of fat free dry matter (P<0.001). The results showed that the addition of phytase to piglet diets low in P led to better utilisation of phytate-P and consequently better piglet performance.
The effect of supplementing leaves of four tannin‐rich plant species with polyethylene glycol 6000 (PEG) on nutrient intake and digestibility as well as on weight gain, feed conversion ratio (FCR) ...and N retention of zebu bulls (Bos indicus) was studied. Leaves of Albizia gummifera, Grewia ferruginea, Prunus africana and Syzygium guineense, containing, respectively, 85, 55, 76 and 172 g condensed tannins (CT) per kg dry matter (DM), were combined with natural pasture hay in a ratio of 40:60 on DM basis. The four diets were fed both without and with addition of PEG, at a dose of 40 g per kg DM, to eight zebu bulls during trials of 25 days in an 8 × 8 randomized crossover design. Supplementation with PEG increased nutrient intake, digestibility, FCR, N retention and average daily gain (p < 0.01). A diet × PEG interaction was observed for nutrient intake as well as for crude protein, neutral detergent fibre and acid detergent fibre digestibility (p < 0.05), but the effect size of PEG addition could not be attributed to the CT content as such, and also digestibility without PEG was not related to CT content of the diets. The reason why the efficacy of PEG addition did not relate to the CT content pointed the need to evaluate other factors that can help to predict the efficacy of PEG, for example, tannin type or interaction with other nutrients.
This study was designed to examine the effect of crude fibre (CF) content and particle size of the diet on growth performance, carcass yield and gastric mucosa integrity. The experimental design was ...a 2×2 factorial trial with 192 pigs fed from 24 to 110kg bodyweight. Four diets were compared: (1) low fibre finely ground; (2) low fibre coarsely ground; (3) high fibre finely ground; and (4) high fibre coarsely ground. All ingredients were ground before mixing.
The high fibre coarsely ground diet resulted in the fewest lesions in the gastric pars oesophagea (P<0.001). Coarse grinding also resulted in the lowest urease activity in the stomach (P=0.006). The feed conversion ratio was worse on the coarsely ground diet than on the finely ground diet (P=0.038), whereas carcass yield was lower for pigs on the high fibre diet vs. the low fibre diet (P<0.001). Coarse grinding feed ingredients in a growing pig diet that is high in CF may reduce macroscopic lesions of the pars oesophagea but such a diet was accompanied in this study by inferior carcass yield.
The effect of technological treatments on the performances from 1 week after weaning until slaughter and on the gastric mucosa integrity of growing-finishing pigs at slaughter was investigated. We ...compared a diet expanded at high pressure and temperature (expandate) with a diet expanded under milder conditions that was subsequently pelleted and crumbled (crumble) and an untreated control diet (meal). At weaning, a total of 180 pigs (8.4±0.8kg) were divided over 30 pens of 6 animals, with 10 pens per treatment. Feed structure had a clear impact on performance results. However, while the expanded and the crumbled feed was used more efficiently (P=0.003), feed intake was considerably higher on the meal feed (P=0.003). Between start and slaughter, this led to a similar growth in the three groups (P=0.898). Apparent faecal digestibility of dry matter (P=0.843) or crude protein (P=0.726) did not differ between the diets. The ulcer score was affected by the feed structure (P<0.001). Pigs on the meal diet had the lowest ulcer score, those on the expandate an intermediate score and those on the crumbled diet the highest score, with all diets being significantly different from each other (P<0.05). The number of Helicobacter suis bacteria per gram of mucus was lower on the meal than on the expandate or the crumbled feed. In conclusion, it can be stated that expanding and pelleting improved feed efficiency of growing-finishing pigs. However, these technological treatments had a negative impact on gastric mucosa integrity and were associated with an increased H. suis colonisation.
The objective of the present study was to calculate an optimal harvest period for both fresh and ensiled samples of forage maize and to calculate a set of harvest dates (called a harvest window), for ...which the variety ranking of the fresh forage corresponds with the variety ranking at the optimal harvest period calculated from the ensiled forage. Forage maize is fed almost exclusively as silage, but official variety trials with silage maize determine quality parameters in fresh (i.e. non-preserved) forage. Eight silage maize varieties were monitored at six harvest dates (from 25 to 40% dry matter content) in Merelbeke (Belgium) in 2013–15. At each harvest date, fresh samples were taken and half of the sampled material was ensiled in micro silos for 20 weeks. An optimal harvest period was calculated based on frequently measuring starch concentration and organic matter digestibility for both fresh and ensiled forage. Eventually, harvesting the silage maize at a dry matter content of 32–35% guaranteed an optimal harvest period. Based on the results of eight varieties, reporting variety ranks without going through the ensiling process continues to be a scientifically justified practice in Belgian official variety trials. Varieties with a superior fresh quality keep their leading position after ensiling, but variety differences become smaller after ensiling.
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