Search

Molassed sugar beet pulp (Bp) is a human inedible by-product of the sugar industry being a suitable dietary energy alternative to grains particularly in terms of increasing the net food production efficiency of high-producing dairy cattle. However, there are concerns that feeding large amounts of Bp can limit cow’s feed intake, jeopardizing both the production performance and metabolic health especially of high-producing dairy cows that have high energy needs. In the present study dietary inclusion of Bp as a substitute for maize grain was tested in a longitudinal block-randomized experimental design in early lactation high-yielding Simmental cows. The Bp inclusion rates were 0 g/kg (i.e., no Bp inclusion as control), 120 g/kg (12Bp), or 240 g/kg (24Bp) on a dry matter basis. The replacement of maize grain with Bp reduced the human edible input from 135.4 MJ GE/d in the control diet to 50.7 MJ GE/d in the 24Bp diet (P 0.05), whereas dietary fibre digestibility was linearly improved (P = 0.038) with Bp feeding, indicating enhanced rumen health and functioning with Bp feeding. In conclusion, feeding molassed sugar beet pulp as partial substitution of maize until 240 g/kg is a viable alternative that can improve net food production without impairing the cows’ production performance and the metabolic health status of cows while improving the digestibility of fibre.

Made available in DSpace on 2022-04-29T08:36:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Citrus pulp pellets (CPP) and orange fiber (OF) are coproducts of the citrus juice industry. OF is a novel fiber source that contains elevated amounts of soluble fiber and has not yet been studied in dog nutrition. The objectives of this study were to evaluate the inclusion of CPP and OF in dog foods and their effects on the extrusion parameters, the coefficient of total tract apparent digestibility (CTTAD) of nutrients, fermentation end products, and palatability. A control diet (CO) without an added fiber source tested was formulated, and the experimental diets were composed of 30 g/kg, 60 g/kg and 120 g/kg CPP or 60 g/kg OF inclusion (as-fed basis). Extrusion parameters were recorded to determine extruder energy balance and kibble macrostructure. Thirty beagle dogs (3.2 ± 0.7 years; 12.4 ± 1.5 kg body weight) were distributed in a randomized block design with 6 dogs per group to evaluate the CTTAD of nutrients and the fermentation products in feces. The results were analyzed by analysis of variance, and means were compared by polynomial and orthogonal contrasts. The inclusion of CPP and OF reduced motor amperage (P < 0.001), mass pressure (P = 0.002), and specific mechanical energy transference (P < 0.001). Kibble macrostructure was affected by a decrease in expansion and an increase in hardness by CPP and OF inclusions (P < 0.001). Starch gelatinization was reduced by CPP (P < 0.001) but not by OF inclusion (P > 0.05). Total dietary fiber (TDF) intake increased (P < 0.001) with the addition of CPP, with a linear reduction in CTTAD of nutrients and energy (P < 0.05). The OF treatment, however, presented similar CTTAD values of DM and CP to those of the CO diet (P > 0.05). The TDF CTTAD was higher for 60 g/kg OF than for 60 g/kg CPP (P = 0.028). The fecal pH decreased, and total short-chain fatty acids (SCFA), acetic acid, butyric acid, and lactate concentrations increased with CPP and OF inclusion (P < 0.05). However, the diet supplemented with OF induced the production of feces with a lower pH and higher total SCFA concentrations than those of feces produced from CPP inclusion (P < 0.001). The OF diet presented a higher preference (65%) than the CO diet (35%) by dogs (P < 0.05). The CPP and OF were fermentable fiber sources, increasing SCFA and butyric acid concentrations in feces. The OF was more fermentable than CPP, with a limited impact on kibble formation, starch cooking, and CTTAD of nutrients and showing good acceptance on diets by dogs. Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agrárias e Veterinárias Departamento de Clínica e Cirurgia Veterinária Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agrárias e Veterinárias Departamento de Clínica e Cirurgia Veterinária CNPq: 142191/2016-7

The objective of this study was to evaluate the water and nutrient intake, apparent digestibility, productive performance and carcass traits of sheep fed diets containing levels of sisal pulp silage (SPS) in substitution of tifton hay. Forty Santa Ines lambs (average initial body weight of 22 ± 3.4 kg) were randomly distributed among four diets containing 0, 167, 333, and 500 g/kg of SPS in the total dietary dry matter (DM), containing 500 g/kg of concentrate. The experimental period lasted 72 days, after 21 days of adaptation to the diets. Linear and quadratic effects of SPS levels were analyzed using orthogonal contrast. Intake of DM and OM were not affected by the substitution of tifton hay with SPS (P > 0.05). Intake of crude protein (CP), ether extract (EE), neutral digestible fiber (NDF) and acid digestible fiber (ADF) decreased linearly as SPS increased (P 0.05). Sisal pulp silage is a suitable source to feed sheep, since animals showed similar intake and performances and it can be a consistent water source in arid and semiarid regions. Because of moderate concentration of physically effective fiber in the 333 g/kg SPS diet group, we recommend the inclusion of 333 g/kg of SPS in dietary dry matter in combination with tifton hay.

The objectives of this study were to test whether the time-based total fecal collection (TC) method or the index method (IM) using acid-insoluble ash could obtain similar energy values as the reference (RF) method (TC method with marker-to-marker collection procedure) for growing pigs fed fiber-rich ingredients with different solubility. A total of 24 barrows (initial body weight, 33.3 ± 3.4 kg) were assigned to 4 diets and each diet was fed to 6 pigs. Experimental diets included a corn-soybean meal basal diet and 3 fiber-rich diets which were formulated by replacing corn, soybean meal, and soybean oil in the basal diet with 200 g/kg defatted rice bran (DFRB), soybean hulls (SBH), and sugar beet pulp (SBP), respectively. All diets were formulated to contain 10 g/kg celite as a source of acid-insoluble ash to estimate the energy values by the IM method. Each group of pigs was adapted to diets and crates for 7 d, then followed by 5-d feces and urine collections using the time-based procedure and 5-d feces collection using the marker-to-marker procedure, then the same portion of fecal sample collected by the time-based TC method and the RF method for individual pigs were composited into a sample for the IM method. The results showed that the energy values and nutrients digestibility coefficients of each diet estimated by the time-based TC method agreed with the values estimated by the RF method; the IM method with acid-insoluble ash underestimated the energy values and nutrients digestibility coefficients of the SBH diet and the SBP diet compared with the RF method (P

In the scenario of increased reports on boron (B) supplementation in animal diets for beneficial effects, there is inadequate information on B content of animal feeds. The present study was carried out to quantify the level of B in animal feeds commonly used in tropical feeding systems. Samples of a total of 225 feeds were procured. The feed samples were oven dried, ground to 1 mm size and wet digested, filtered using Whatman filter paper (no 42) and volume made up to 100 ml by deionized water. Boron (B) content was estimated using inductively coupled plasma optical emission spectroscopy (ICP-OES). The level of B in fibrous feeds ( n = 83) was higher than in concentrate feeds ( n = 120) and unconventional feeds ( n = 22). The range of B content among the feed samples analyzed ( n = 225) showed a wide range from rice bran to cowpea fodder (0.69–59.1 mg/kg). The spatial distribution of B indicates that most feed samples analyzed showed B content lower than 20 mg/kg with mean and median of 17.7 ± 0.96 and 14.4, respectively. It is evident from the present study that appreciable quantity of B is detected in all the major categories of feedstuffs which was comparable to the levels of essential trace elements like copper and zinc. These findings would facilitate in assessing the supplementary value of tropical feeds for boron.

The objective of this study was to evaluate the effects of different feed particle sizes and fiber sources on nutrient digestibility and short chain fatty acids (SCFA) concentration in different intestinal segments of pigs. Eighteen barrows with T-cannula in the distal ileum were randomly allotted to a 3 × 2 factorial arrangement with 3 different high-fiber diets including corn bran (CB), sugar beet pulp (SBP) and soybean hulls (SH), and 2 different feed particle sizes. The experiment contained 2 periods, and each period lasted for 15 days, including 10 days for diets adaptation, 3 days for fecal collection, and 2 days for ileal digesta collection. The results indicated that coarse diets decreased (P

In total, 504 female broilers were used to study the effects of inclusion of oat hulls (OH) and sugar beet pulp (SBP) in the diet on growth performance, coefficient of total tract apparent retention (CTTAR) and coefficient of apparent ileal digestibility (CAID) of nutrients from 1 to 18 days (d) of age. A control diet based on rice that contained 69 g dietary fibre (16 g crude fibre)/kg was diluted with 25, 50 and 75 g/kg of either OH or SBP. Each of the seven treatments was replicated six times (a cage with 12 chicks). Growth performance and CTTAR of nutrients were recorded at d 6, 12 and 18 and the CAID of organic matter and crude protein were determined at d 18. From d 1 to 18, fibre inclusion did not affect feed intake or body weight gain of the birds. However, feed conversion ratio was improved quadratically (Q) with OH (P

This study determined the chemical composition and metabolizable energy (ME) value for ruminants of seeds and pulps from grape pomaces (GP), which were produced from white and red Vitis vinifera cultivars in Italy and California (USA). Six Italian (i.e., three white and three red) and five California red cultivars were collected after the crush of grape juice had been completed and were ensiled in micro-silos for 45 d. Fresh and ensiled samples were manually sieved to separate seeds from the pulp plus skin fraction and an overall inventory of 44 samples was obtained from the 24 Italian and 20 California samples (i.e., seeds and pulp fractions, fresh or ensiled from 6 or 5 cultivars, respectively). Both in seeds and pulp, the red Italian samples had higher organic matter (P

Ruminal, post-ruminal and total tract protein disappearance of various feeds originating from Iranian plant varieties classified as grains (barley and maize), by-products (sugar beet pulp and wheat bran), protein sources (soybean and cottonseed meals), forages [alfalfa hay and maize silages treated with 16 (MS16) or 24 (MS24) g of urea per kg dry matter (DM)] and halophytes (Atriplex sp., Sauda sp. and Kochia sp.) were evaluated using the in situ mobile bag technique, an in vitro enzyme procedure and a three-step in situ/in vitro enzyme procedure. Linear regression equations were determined between results from the mobile bag technique and the two other procedures. Mean ruminal protein disappearance of grains, by-products, protein sources and forages were higher (P 0.05) on rates of ruminal, post-ruminal and total tract protein disappearance of the various feeds originating from Iranian plant varieties. The best correlation was observed when results of total tract protein disappearance determined by the in vitro method were plotted against the three-step procedure (r2 = 0.66). The coefficient of determination (r2) for the relationship of total tract protein disappearance between the mobile bag technique and in vitro, and three-step procedures were 0.61 and 0.55, respectively.

Chemical composition and nutritive values of by-product feedstuffs (BPF) used for small ruminants were evaluated. Four BPF from groundnut shells (GNS), maize cobs (MC), cassava peels (CaP), and citrus pulp/peels waste (CPPW) were used to prepare complete diets fed to goats and sheep in separate trials. Twelve goats and 16 sheep 16–18 months old weighing on average 12.96±0.28 and 14.05±0.18 kg, were divided into three and four groups, respectively, and used in two separate growth and digestibility studies. In vitro digestibility trial was carried out. In vivo and in vitro data were compared. Chemical composition of BPF differed in nutrient contents. MC had the least crude protein content (3.4%). CaP and CPPW had low NDF and ADF. GNS and MC were higher in cell wall constituents. Voluntary DMI was expressed as g/kg live weight (LW) per day and this ranged between 58.0–62.0 g/kg LW per day in goats and 70.0–83.0 g/kg LW per day in sheep. DM and CP digestibility were better (P>0.05) in goats fed CaP diet compared to the other BPF. NDF digestibility was better (P>0.05) in the GNS fed group compared to MC and CaP groups. GE was lower in CaP fed goats than in the others. Nutrient digestibility of the four by-products was better (P>0.05) in sheep that received CPPW diet. Other by-products (GNS, MC, CaP) digestibility followed the trend observed in goats. Net gas production, DM, NDF and OM digestibility and metabolizable energy (ME, MJ/kg of DM) were significantly different among the BPF (P

Forty-eight Suffolk Mule entire male lambs (22.3 kg average live weight, two months old) were used to study the effects of addition of sodium bicarbonate and increasing quantities of molassed sugar beet pulp (MSBP) to diets based on barley grain (780 g kg ˇ1 fresh weight and approximately iso-energetic and iso-nitrogenous). Measurements were made of dry matter (DM) intake, growth, some ruminal and blood plasma metabolites and hormone profiles and body composition. The animals were allocated by randomised block design on the basis of live weight to one of six dietary treatments and an initial slaughter control group (na 7 and mean live weighta 22.3 kg per treatment). Animals in the initial slaughter control group were slaughtered on Day 1 of the study in which barley was supplemented with sodium bicarbonate (15 g kg ˇ1 fresh weight) (Experiment A) or replaced with increasing quantities of MSBP in a separate experiment (B) to provide diets containing 75, 50, 25 and 0% of the maximum quantity of barley (Experiment B). The diets had similar in vitro dry matter digestibility and contained similar estimated values for metabolisable energy concentration. In Experiment A, the inclusion of sodium bicarbonate had no significant effect on live weight gain, DM intake, feed utilisation efficiency, ammonia concentration and the molar proportion of ruminal volatile fatty acids, rumen fluid, carcass and soft tissue characteristics and composition. In Experiment B, increases in level of barley in the diet had no effect on ruminal pH, but linearly increased the molar proportion of propionate in rumen fluid (p < 0.01), hot- and cold-carcass weights (p < 0.01), empty body weight (p < 0.01), perirenal and retroperitoneal fat (p < 0.05) and gain of crude protein in cold carcass (p < 0.01). Evidence was also obtained for decreases in

An experiment was carried out to compare the digestibility of five concentrate ingredients (barley, beet pulp, citrus pulp, maize gluten feed and grain screenings) in cattle or sheep, fed at ≈1.2 maintenance. Four wether sheep and four steers were fed each concentrate, which comprised ≈800 g/kg of the dietary dry matter (DM). The remaining 200 g/kg was a hay/soyabean meal mixture whose digestibility was determined simultaneously in another four sheep and cattle. Following diet introduction and adaptation, faeces were collected for a 10-day period. Across diets, there was no difference (p >0.05) between sheep and cattle in digestibility of organic matter (OM, 0.784 and 0.78, respectively, standard error of the difference (s.e.d.), 0.0049), crude protein (0.586 and 0.577, respectively, s.e.d. 0.0192), or neutral detergent fibre (0.632 and 0.628, respectively, s.e.d. 0.0116). However, cattle digested the OM (0.749 vs. 0.724, p 0.05) between sheep and cattle with any of the other four feeds. These results do not support previous conclusions that sheep digest concentrates better than cattle, but they do suggest that there are differences within specific feeds.

Four rabbit diets were formulated to study the effect of a progressive inclusion (0, 100, 200, and 300 g kg − 1) of sugarbeet pulp (SBP) substitute for alfalfa hay (AH). The control diet contained 500g kg−1 of AH and 190 g kg−1 acid detergent fibre (ADF) on a DM basis. In Experiment 1, 32 Californian x New Zealand White rabbits were used to determine dietary nutrient digestibility. The inclusion of SBP quadratically increased (P < 0.01) digestibility coefficients of NDF, ADF and gross energy, showing a maximum for the diet containing 200g kg−1 of SBP. Crude protein digestibility linearly increased with SBP inclusion (P < 0.05). In Experiment 2, 36 rabbits fed the same diets as in Experiment 1 were used to determine several digestive traits and the efficiency of utilization of dietary energy for growth. Dietary inclusion of SBP did not affect either the concentrations of ammonia (66 mg of N-NH3 per litre) and total VFA (50.3 mmol l−1) or the molar proportion of VFA (767, 62 and 171 mmol mol−1 VFA of acetate, propionate and butyrate, respectively) in the cecal digesta. The concentration of starch in the ileal digesta was also unaffected by diet (7.7 g kg−1 of DM, as average). The weight of cecal contents increased (P < 0.05) and the pH of cecal contents decreased (P < 0.05) when SBP proportion in the diet increased. The efficiency of utilization of dietary digestible energy for growth was not influenced by dietary SBP inclusion (0.224, as average).

The nutrient composition of nine by-product feedstuffs (BPF) was determined. BPF were selected based on economic importance to the dairy industry, nutritional value, and availability. Three to nine different samples for each BPF were obtained throughout California. A total of 51 samples were collected: nine beet pulp (BP), eight rice bran (RB), seven almond hulls (AH), four citrus pulp (CT), five bakery waste (BW), eight wheat mill run (WMR), four brewers grains (BG), three distillery grains (DG), and three soy hulls (SH) samples. Chemical analyses measured included dry matter, ash, crude protein (CP), fiber fractions, macrominerals, and microminerals. The average chemical analyses determined for each BPF were compared with average values reported by the National Research Council (NRC). Considerable variation within a given BPF was observed in the present study. For example, BP was found to contain 18.81% acid detergent fiber (ADF) while the NRC reported an average composition of 25% ADF. The ether extract content of RB was found to be 20.48% compared with 15.1% reported by NRC. Much of this variability was related to how the commodity was handled during or after processing. In the second part of this study, two theoretical diets were formulated to calculate the effect of nutrient variability on diet composition. The BPF compositions of the two diets were 27% and 50% in Diet 1 and Diet 2, respectively. Specific by-products sources of BP, RB, DG, and SH were compared with the NRC diet composition used in the initial diet formulation. As the proportion of BPF in the diet was increased (Diet 2) nutrient composition of the diet was more variable with CP content ranging from 14.30 to 15.20%. Similar changes to those observed for CP were observed for the other chemical components. The effect of variability in by-product composition was more evident when evaluated on a concentrate mix basis. Variability in the chemical component of BPF influenced the composition of both the total diet and the concentrate mix, and the magnitude of effect depended upon the contribution of BPF to the total ration and the nutrient of interest.

The effect of ammonia treatment and supplementation of barley straw with increasing levels (0, 200, 400 and 600 g day −1 ) of meadow grass hay (H), rolled barley (B) or pelleted sugar-beet pulp (P) on ruminal characteristics and straw degradation was studied using eight adult ewes, divided in two groups, receiving either untreated (US) or ammonia treated (TS) straw, supplemented with H, B or P consecutively. Urea (30 g kg −1 straw) was added to US 24 h before feeding. Sheep fed US showed higher ammonia-N (NH 3 N) concentration than those fed TS, either as the only feed (17.5 and 12.3 mg per 100 ml) or supplemented (15.0 and 12.7 mg per 100 ml). There was no effect of ammoniation over rumen pH or total volatile fatty acid (VFA) concentration. Supplementation with B or P depressed pH and enhanced VFA concentration, whereas H did not have any great effect. Extent of straw rumen degradation was enhanced by ammoniation (maximum degradation of 593 and 741 g kg −1 for US and TS), but rate of degradation and lag time remained unaffected. Both rate and extent of straw degradation were decreased to a similar extent when supplemented with B or P, while with H this effect was only noticeable when it was included in the diet at 600 g day −1 .

Whole crop wheat (WCW) was harvested at 550–650 g dry matter (DM) kg−1 in each of 3 years. Each crop was mixed with 40 kg urea t−1 DM and stored anaerobically. In Experiment 1, nine Holstein Friesian heifers of 370 kg liveweight were offered WCW ad libitum in a 3 × 3 Latin square design. The three treatments were: no supplement (W); a supplement of 2.0 kg day−1 molassed sugar beet pulp (WB); a supplement of 1.8 kg day−1 molassed sugar beet pulp + 0.2 kg day−1 fishmeal (WBF). Experiment 2 was similar except that WB consisted of molassed sugar beet pulp fed at 20% of WCW DM intake and WBF consisted of molassed sugar beet pulp fed at 15% of WCW DM intake and fishmeal at 5%. This method of proportionate allocation of feeds enabled a comparison to be made of the effect of liveweight (three groups with initial liveweights of 136, 267 and 340 kg). In both experiments, intake and digestibility were measured. In Experiments 1 and 2, the mean digestible organic matter in the dry matter (DOMD) of the WCW was 654 g kg−1 and 635 g kg−1, respectively. The supplements tended to increase neutral detergent fibre and acid detergent fibre digestibility and reduce starch digestibility. The mean DM intake of WCW was depressed by the WBF supplement. There were no significant effects of heifer size on digestibility but intake per kilogram liveweight declined with increasing size. Experiment 3 had a continuous design with 20 Holstein Friesian heifers of 165 kg liveweight. The treatments were: W (as above); a supplement of 1.0 kg day−1 molassed sugar beet pulp (WB); a supplement of 0.2 kg day−1 fishmeal (WF); a supplement of 0.8 kg day−1 molassed sugar beet pulp + 0.2 kg day−1 fishmeal (WBF). The mean liveweight gains over 9 weeks for W, WB, WF and WBF respectively were 0.65 kg day−1, 0.79 kg day−1, 0.76 kg day−1 and 0.88 kg day−1. These were lower for all treatments than predicted from estimated metabolisable energy (ME) intakes. The possible reasons for this are discussed. The blood urea levels for treatment W were reduced by treatment WB, and levels increased for all treatments over time.

Mixed diets, for which information relating to various chemical measurements and rates of inclusion of certain raw materials (independent variables) and their nutritive value for rabbits (dependent variables) as assessed in terms of digestible energy (DE) and the coefficient of digestibility of gross energy (GE D ) was available, were combined in a series of correlation matrices and step-wise linear regression analyses. GE D removes the possible effect of variability in gross energy value on DE values and is reported. In general, GE D was better correlated to acid detergent fibre (ADF) than crude fibre (CF). A general equation was derived: GE D = 0.867 − 0.0012 ADF (g kg −1 DM) R 2 = 0.888. Closer inspection of individual points revealed that diets based on added fat, beet pulp, citrus pulp and straw at levels higher than 200 g kg −1 behaved atypically. Separate prediction equations were derived for each of these groups of diets. Multiple regression analyses considered more than one independent variable, but gave only marginal improvements in terms of the accuracy of prediction of GE D . Addition of rates of inclusion of feedstuffs as independent variables revealed that the chemical analyses employed were insensitive to changes in nutritive value arising from additions of fat, pulps and straw. These feedstuffs need to be characterised further and general prediction equations should not be applied to diets in which they are contained.

The feasibility of ensiling pressed sugar-beet pulp alone or supplemented with molasses and urea or laying hen excreta (LHE) was evaluated by measuring fermentation characteristics of the silages. The volatile fatty acids, lactic acid and NH3 contents were significantly higher (P < 0.05) for pulp supplemented with LHE. All pathogens (coliforms, Streptococci, Staphylococci, yeasts and moulds) were eliminated after ensiling, except Clostridia but these germs were present in very small quantities (less than 100 germs g−1). A second experiment was carried out with 12 adult wethers in a complete random block scheme in order to determine the apparent digestibility of the main constituents of three diets consisting of pressed pulp supplemented with molasses and urea (P-MU), LHE (P-LHE) or soybean meal (P-SM). The diets were supplemented with 10% hay of known digestibility and this latter value was deducted from the measured digestibilities in order to obtain those of the studied diets alone. The crude protein digestibility was significantly higher for P-MU (P < 0.05), and that of organic matter significantly lower for P-LHE (P < 0.05). Crude fibre digestibilities significantly differed for the three diets (P < 0.05) in the following order: P-LHE < P-SM < P-MU. In a third experiment, three wethers fitted with rumen and duodenal cannulas were given, in a Latin-square design, one of the three studied diets. The NH3 contents and pH of the rumen fluids were significantly higher (P< 0.05) for P-LHE whereas the volatile fatty acid profile was the same for the three diets. The yield in bacterial N synthesis, estimated with the diaminopimelic acid method, was significantly higher (P < 0.01) for P-MU: 45.3 g bacterial N kg−1 organic matter digested in the rumen versus 36.5 g and 33.9 g for P-SM and P-LHE, respectively. The proportion of bacterial N at the duodenal level was significantly lower (P < 0.01) for P-SM (58% versus 75% and 73%, respectively for P-MU and P-LHE). The duodenal flow of amino acids was significantly lower (P < 0.001) for P-LHE: 113 g day−1 versus 147 g day−1 and 148 g day−1 for P-SM and P-MU, respectively. It was concluded that pulp is very easy to conserve by ensiling, even when mixed with LHE and, thanks to the high degradability of its fibre in the rumen, it is a very good energy source that may be supplemented by non-protein nitrogen. The bacterial protein synthesis is optimised by supplementation with urea and molasses.

Digestibility of beet and cane molasses was tested in vivo with wether sheep at two levels of inclusion of molasses in the ration (15 and 30%) as well as in vitro with rumen fluid. In vivo, cane molasses was less digestible than beet molasses, irrespective of the level of inclusion in the ration. The level of inclusion of the molasses did not have a significant effect on the calculated organic matter digestibility of the products. Increasing the ratio of molasses to hay (or hay + sugar beet pulp) linearly increased in vitro OM digestibility of the mixtures irrespective of the molasses type tested. Digestibility in vitro of cane molasses was only slightly lower than that of beet molasses. Chemical characteristics of both molasses are discussed in relation to possible explanations for the differences between results obtained in vitro and in vivo.

Twenty-four male weanling African giant rats were allocated to four treatment groups in a 16-week trial. Their diets were based on (1) maize, (2) cassava peel, (3) cassava whole tuber and (4) cassava pulp. Hydrocyanic acid (HCN) content of diets was 0, 597, 150 and 110 mg/kg, respectively. Diets were isocaloric and isonitrogenous. Feed consumption was similar on all diets. Growth rate, feed efficiency and protein efficiency ratio were better ( P P

Groups of 3 castrated male pigs (45–50 kg), housed in metabolism crates, were offered basal diets alone or with increasing levels of addition of straw, oatfeed or sugar-beet pulp. The excretion of nitrogen in the faeces, expressed as a proportion of nitrogen intake, tended to increase as the level of fibre addition increased, the effect being significant (P Urinary nitrogen excretion, expressed in the same manner, tended to fall as more fibre was consumed, the effect being significant (P

Five experiments were conducted to investigate the dietary factors within the rumen environment which could contribute to changes in the degradation of barley straw. Degradation was measured by recording the losses of dry matter (DM) from samples of straw incubated in nylon bags in the rumen for various periods of time. Three sources of supplementary energy (sugar-beet pulp, citrus pulp and dried grass) and two sources of protein (soya-bean meal and fish meal) were investigated for their ability to increase degradation of straw when given as supplements to untreated straw. The untreated straw used in these experiments was adequately supplemented with rumen-degradable nitrogen, sulphur, vitamins and minerals. Unmolassed sugar-beet pulp and dried grass, when given at a level of 150 g kg−1 straw DM, increased both the rate and extent of degradation of straw DM. Citrus pulp and soya-bean meal had no effect on the degradation of straw, while fish meal appeared to have a small effect. It was concluded that in particular digestible cellulose and/or hemicellulose improved the conditions in the rumen for straw fibre degradation in animals given straw diets.

Fresh artichoke by-product, pepper and cauliflower residues, dried tomato pulp and fresh or ensiled apple pomace were fed, together with alfalfa hay, to adult ewes in four diets including 20, 40, 60 and 80% of each by-product, and organic matter digestibility (OMD) was estimated by the regression and difference methods. The OMD of ensiled artichoke and pea haulms was also determined directly giving both by-products as a whole diet. The OMD varied linearly with the dietary level of inclusion of each by-product, except for diets including pepper residues, where digestibility was similar tothat of the alfalfa hay. The digestible organic matter (DOM) content (g kg −1 DM) of fresh artichoke, pea haulms, apple pomace, pepper and cauliflower residues and dried tomato pulp was estimated to be 750, 650, 847, 615, 679 and 449, respectively, and that of ensiled artichoke, pea haulms and apple pomace 669, 508 and 739, respectively. Dry matter disappearances after in vitro incubation with rumen liquor-pepsin or pepsin-cellulase solutions and after 24 as well as 48 h of in situ incubation were determined to study their usefulness as predictors of OMD compared with several chemical parameters. The most accurate predictions were obtained with the in situ method after 48 h of incubation ( r = 0.97; RSD = ± 3.03) followed by the rumen liquor-pepsin procedure ( r = 0.94; RSD = ± 4.62) and pepsin-cellulase bioassay ( r = 0.88; RSD = ± 6.09). Chemical parameters proved to be poor predictors of OMD for this sort of by-product (RSD ranged from ± 7.00 to ± 11.96).

A meta-analysis was conducted to elucidate the factors affecting drinking water intake (DWI) in order to develop new DWI empricial predictive models for lactating dairy cows and to compare with existing models. A large dataset, containing 262 experimental diets from 75 experiments published in 65 peer-reviewed papers was built. Selected explanatory variables were grouped into animal (body weight (BW); BW0.75; milk yield), diet composition (dry matter; ash; sodium; potassium; crude protein (CP); neutral detergent fiber), dry matter intake (DMI) and environment (mean air temperature and relative humidity) inputs. To develop the predictive models, the dataset (peer-reviewed papers) was randomly divided into two subsets for statistical analyses. The first data subset was used to develop equations to predict DWI (41 peer-reviewed papers; 47 experiments; 157 experimental diets), and the second data subset was used to assess the adequacy of the predictive models (24 peer-reviewed papers; 28 experiments; 105 experimental diets). Ash was the main diet input affecting DWI in lactating dairy cows, while BW0.75 affected DWI more than milk yield. Use of dietary characteristics (DM, ash and CP) and DMI as inputs could be enough to predict DWI as accurately as more complete models. Dry matter intake as predictive variable does not improve DWI prediction in models with only animal (BW0.75 and milk yield) as input, but it substantially improves prediction of models without use of animal as input. Among the existing models evaluated, those developed from just one experiment (Castle and Thomas, 1975; Little and Shaw, 1978; Murphy et al., 1983; Stockdale and King, 1983; Dahlborn et al., 1998) had poor prediction quality. We proposed the use of two models (diet II and animal + diet models) that presented the lowest root mean square prediction error (RMSPE) to predict DWI in lactating dairy cows.

This paper has the following objectives: i) evaluate which of the two techniques, n-alkanes or faecal crude protein (fCP), and their equations had the highest accuracy in estimating DM intake by sheep; and ii) evaluate which ratio option of n-alkanes (C31:C32 or C33:C32) was most accurate in estimating sheep DM intake. The experimental design was a randomised complete block with three replicates (paddocks) and repeated measures on time (periods), arranged in a two-level factorial design, with two stocking methods (continuous and rotational) and two grazing intensities (moderate and low). In general, both the fCP and n-alkanes techniques and equations tested are potential to estimate DM intake by sheep grazing Italian ryegrass, however, the equation proposed by Azevedo et al. (2014) and De-Stefani Aguiar et al. (2013) are the most accurate (lower CV), respectively. The n-alkanes ratio C31:C32 is the more accurate predictor of DM intake by sheep grazing Italian ryegrass pastures.

The objective of this meta-analysis was to investigate the effects of substitution of steam flaked corn (SFC) instead of finely ground corn (FGC) on dry matter (DM) intake, nutrients digestibility, milk yield (MY), milk composition, and rumen fermentation of dairy cows. A literature search was conducted to identify papers published from 1990 to 2020. Effect size for all outcomes was reported as standardized means difference (SMD) with 95 % confidence intervals. Heterogeneity was determined using Q test and I2 statistic, while meta-regression was used to examine factors influencing heterogeneity. The meta-analysis results indicated no effect of SFC inclusion on DM intake (SMD = -0.214; 95 % CI = -0.549 to 0.121; P = 0.210). Starch digestibility (SMD = 0.987; 95 % CI = 0.668–1.307; P

There is growing awareness that variability in the nutritional quality of Ca sources has significant effects on gastrointestinal pH, P and amino acid digestibility, exogenous enzyme efficacy and the microbial population in the gastrointestinal tract of broilers. In this regard, the interest in moving toward a digestible Ca system is gaining traction and the apparent ileal digestibility (AID) or standardized ileal digestibility (SID) coefficients for Ca in ingredients, such as limestone (n = 55), dicalcium phosphate (DCP; n = 21), meat and bone meal (MBM; n = 20), monocalcium phosphate (MCP; n = 12), and plant-based ingredients are available. The aim of this review was to compile the literature evaluating Ca digestibility of feed ingredients for broilers, highlight factors that may influence the digestibility coefficients, and suggest recommendations to move toward a digestible Ca system. There were 11 papers published between 1974 and 2019 focused on the evaluation of Ca digestibility of feed ingredients for broilers. The average ileal Ca digestibility coefficient for limestone was 0.53, DCP was 0.42, MCP was 0.35 and MBM was 0.46. There were no differences in the AID or SID Ca digestibility coefficients within ingredient. The ileal Ca digestibility coefficient for limestone increased (quadratic, P 1:1 or to 16 h for diets with a Ca:NPP ratio

The potential of phytobiotics, also referred phytogenics or botanical to improve animal productivity has been highlighted. However, consensus has not been reached on the use of garlic, one of such phytobiotics to boost productivity of laying hens. The objectives of this meta-analysis were to assess the effectiveness of supplementation with garlic on feed intake (FI), feed conversion ratio (FCR), hen day egg production (HDEP) and egg quality attributes of lay hens. Databases [Scopus, Google scholar, and Access to Global Online Research in Agriculture (AGORA)] were searched for peer-reviewed randomized controlled trials (RCTs) published in English. Criteria for inclusion in the meta-analysis were information on moderators (breed, preparation form of garlic, treatment duration, age of hen at the beginning of garlic intervention, country where the study was performed, number of chickens included in the study, inclusion level of garlic), an adequate description of randomization, egg production and egg quality data, and associated measures of variance such as standard deviation (SD), standard error (SE) and P - values. Nineteen (19) out of 53 research papers met the criteria for inclusion in the meta-analysis. All analyses were conducted using the Open Meta-analyst for Ecology and Evolution (OpenMEE) software. Overall pooled results revealed that garlic supplementation increased HDEP by 0.322% [95% confidence interval (CI) = 0.211 to 0.432], egg mass by 0.486 g/day/hen [95% CI = 0.163 to 0.810], egg weight by 0.069 g [95% CI = 0.001 to 0.136], egg shell thickness by 0.259 mm [95% CI = 0.160 to 0.358] and egg shell weight by 0.219 g [95% CI = 0.087 to 0.350] relative to controls, taking cognizance of publication bias and heterogeneity. Chickens fed diets with or without garlic had comparable FCR. Results suggest that there was no evidence of treatment effect on FI and Haugh unit. Subgroup analysis found that studies that used garlic extract had significant egg weight while studies that used garlic powder and oil had similar egg weight. Meta-regression analysis showed that study country, breed, hen’s age, garlic preparation form, inclusion level of garlic, number of hens included in the study and treatment duration were predictors of the study effect. The results of this meta-analysis revealed that layers on dietary garlic supplementation had significantly increased HDEP, egg mass, egg weight, eggshell thickness and eggshell weight compared to controls, although the egg production data for the layers (both treatment and control groups) of specific age, breeds, strain and lines used for the analysis were within their respective target data.

A meta-analysis of the impact of forage particle size (FPS) on chewing activity, rumen pH and volatile fatty acids (VFA) in dairy cattle was conducted following a search of the literature. A meta-regression was conducted to test the additional effect of forage level, source and preservation method on the heterogeneity of the results of FPS on the same target variables. A total of 42 papers and 86 trials with the change of FPS in the diet of dairy cattle were identified. Decreasing of FPS in the diet from an average of 10.0 ± 4.9–6.7 ± 4.11 mm lowered eating (P 500 g/kg forage). Forage preservation method was another source of variation accounting for high heterogeneity in the results of FPS in which eating (P = 0.03), rumination (P = 0.01), and total chewing (P = 0.02) activity decreased only in silage-based diets but not in hay-based diets. Total VFA concentration (P

An experiment was conducted to validate the use of n-alkanes technique to estimate feed intake and digestibility in cattle under the sub-humid tropical conditions. The experiment was conducted using Zebu type Arsi steers fed natural pasture at different levels of dry matter (DM) intake (DMI). Eight steers, blocked into four groups based on body weight (BW), were used for the experiment. The steers in each group were randomly assigned to either low intake (11 g DM/kg BW) or high intake (ad libitum at 50 g refusal per kg diet offered) diet. The steers were housed in individual pens, and each steer was dosed twice daily with paper bung containing 400 mg C32 alkane using a balling gun for 15 days. Steers received pasture diets twice a day (at 8:00 and 16:00 h) with half of the daily allocation offered at each feeding. Feed intake, refusal, and total fecal outputs were recorded, weighed and sub sampled for proximate and n-alkane concentrations analysis. The odd-chain n-alkanes comprised the highest percentage during both wet and dry seasons. The alkanes C29, C31 and C33 were present in concentrations greater than 59 mg/kg DM in the two seasons. The mean fecal recovery rates ranged from 0.49 to 0.79 for low and 0.62 to 0.99 for high intake group, respectively during the wet season, whereas 0.68 to –1.05 for low and 0.61 to 0.9 for high intake group during the dry season, respectively. The DMI predictions using the double n-alkane technique were affected by season (P

Emissions of CH 4 methane from beef cattle grazing pastures characteristic of northern Australia are yet to be reliably quantified. Poor quality pastures and low animal productivity are typically associated with high CH 4 emissions/unit animal product. Our study reports two independent methodologies to quantify CH 4 emissions from beef cattle at herd scale and from individual animals. The first method identifies each animal within a herd ( n = 18) as a point source of CH 4 . Emissions at the herd scale were estimated with a backward Lagrangian stochastic (bLs) dispersion model. This model used atmospheric turbulence data and line-averaged concentrations of CH 4 measured with an open-path laser and inputs (ppm) from 5 paths across 1 ha Rhodes grass ( Chloris gayana ) dominated pastures that were flat and free of obstructions. The second method used open circuit respiration chambers to measure 24 h CH 4 emissions from 18 steers fed freshly cut forage from the same pasture. The CH 4 emissions determined using the dispersion method were 136.1 ± 21.5 g/d or 29.7 ± 3.70 g/kg dry matter (DM) intake and 114 ± 5.1 g/d or 30.1 ± 2.19 g/kg DM intake using open circuit respiration chambers. Estimates of CH 4 emissions based on predictive algorithms for beef cattle grazing similar pastures range from 82.7 ± 3.98 g/d to 112.7 ± 2.57 g/d. Additional studies with different tropical pastures and herds are required to obtain estimated CH 4 emission values for further comparisons with predictions from the Australian Greenhouse Gas Inventory and those currently reported in the literature for beef cattle. This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson .

The sulphur hexafluoride (SF6) tracer technique is a means to estimate CH4 emissions from individual ruminants, particularly whilst grazing. The success of the SF6 technique is reliant upon accurate determination of the release rate of SF6 gas from the permeation tubes (PT). Our study aimed to determine effects of SF6 PT rumen residence time on the release rate of SF6 gas and calculated CH4 production (as g CH4/d) in grazing red deer. The CH4 emissions of red deer stags grazing permanent perennial ryegrass based pasture were estimated daily for 5 d at 4.5, 6.5, 9.0 and 11.5 months of age, corresponding to a PT release period of 55, 111, 195 and 258 d. Permeation tube charge time refers to the number of days since PT were charged with SF6. The PT were recovered from 3 deer after the second CH4 measurement and from the remaining 10 deer at the end of the experiment. Release rates of SF6 gas from PT were determined pre-insertion to the rumen (i.e., uncorrected SF6 release rates), or by pre-insertion SF6 release rate with adjustment for SF6 release rates from PT recovered at the termination of the experiment (i.e., corrected SF6 release rates), after the PT had resided in the rumen of red deer for 212 d. A difference of 12.8% between corrected and uncorrected SF6 release rates (P=0.07) occurred after 9 d of PT rumen residence. In contrast, after 65, 150 and 212 d of PT residence, corrected release rates were lower (P This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Methane is a potent greenhouse gas and its release to the atmosphere is widely believed to contribute to global warming. Ruminal enteric CH4 production represents a loss of 2–15% of the animal's gross energy (GE) intake and contributes nearly 20% of US CH4 emissions. Studies have evaluated the CH4 inhibiting potential of select short chain nitrocompounds, such as nitroethane, but results demonstrating their effects on ruminant exhaled CH4 emissions are lacking. Our study determined effects of oral nitroethane administration on CH4 emissions, accumulations of volatile fatty acids (VFA) and on ruminal CH4 producing activity in steers fed a forage based diet containing 8.8 MJ/kg of metabolizable energy on a dry matter (DM) basis. Effects of nitroethane administration on ruminal nitroethane reducing activity were also determined. Holstein steers (n = 24) of 317 ± 6.5 kg body weight (BW) were assigned to 4 treatments that included: 0, 30, 60 and 120 mg nitroethane/kg BW/d. Treatments were administered via oral gavage twice daily at 08:00 and 16:00 h for 8 d. DM intake decreased quadratically as level of nitroethane increased with steers administered 60 and 120 mg nitroethane/kg BW consuming 14 and 7% lower DM, respectively, than steers administered 0 or 30 mg nitroethane/kg BW. Methane emissions as a proportion of GE intake and ruminal CH4 producing activity both decreased linearly (P This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

In many in vitro studies feeds are dried in heated ovens with forced air ventilation and milled through a screen with 1 mm apertures to obtain a physically representative small sample. Drying methods involving heat have been shown to change the chemical composition of feeds, and it is possible that changes in the chemical composition during thermal drying could affect in vitro rumen CH 4 output measured on the samples. Hence, samples are often dried by freeze drying. The objective of this study was to compare effects of freeze drying at −55 °C for 72 h versus thermal drying at 40 °C for 48 h on the chemical composition and CH 4 output of perennial ryegrass samples collected at 5 stages of primary growth ( i.e. , 12 May, 26 May, 9 June, 23 June, 7 July) using an in vitro rumen gas production technique. The magnitude of the changes in chemical composition due to drying method was small and not biologically important, and drying method had no effect on CH 4 output. With advancing maturity at harvest, digestibility of the herbage declined. Methane output/g dry matter (DM) incubated decreased linearly while CH 4 output/g DM digested increased linearly with advancing grass maturity. Thermal drying on a range of grass samples had a similar effect to freeze drying on in vitro rumen CH 4 output, reflecting the small degree of change in chemical composition. This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

The purpose of this study was to explore the relationships between odd- and branched-chain fatty acids (OBCFA) in milk with calculated enteric CH4 production for lactating dairy cows using multiple linear regression (MLR), partial least squares regression (PLS) and a genetic algorithm approach (GA). A dataset collected from 13 experiments containing 224 paired observations of measured acetate, propionate and butyrate proportions in rumen fluid VFA and 7 measured OBCFA was used. Methane proportion (mmol/mol VFA) was calculated from acetate, propionate and butyrate and expressed relative to the sum of these volatile fatty acids (VFA). Calculated CH4 production was related to milk OBCFA using MLR and PLS, resulting in a linear prediction model. The GA approach resulted in a model which predicted rumen VFA proportions of total VFA from milk OBCFA. Methane proportion was calculated from predicted acetate, propionate and butyrate proportions in total VFA based on rumen stoichiometry and compared with CH4 proportion calculated from measured VFA proportions. The prediction error was low (i.e., root mean square prediction error This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

This paper reports effects of chestnut and mimosa tannins on N utilisation in sheep. Tannins were added to grass either at ensilage or incorporated into grass silage at feeding. The study used an 8 × 5 incomplete Latin Square design with eight mature wether sheep and five 21-day periods. Tannin additions reduced in vivo apparent digestibilities of dry matter (DM), organic matter (OM) and neutral detergent fibre (aNDFom) compared with the untreated control silage (P

The concept of residual feed intake (RFI), in determining differences among animals in converting feed into body tissue, was first raised in 1963. Feed efficiency is typically calculated as a function of liveweight gain (LWG) and feed intake (FI). Historically two versions of the same model were proposed, one where FI was adjusted for liveweight (LW) and LWG, and the other where LWG was adjusted for FI and LW. Variation in LWG or FI could then be partitioned into two parts; that which is expected and can be attributed to differences in FI or LWG; and that which is the residual portion, which is the deviation from the expected value based on regression, and therefore not accounted for by differences in FI or LWG. Based on this definition, it is the residual portion which is the measure of efficiency. Both within a livestock industry and between different livestock industries there is no set model for calculating RFI. This paper evaluated four models used to calculate RFI and one model used to calculate residual LWG (RLWG) at a standard level of nutrition. They were the main model currently in use in the Australian beef cattle industry (RFIB), the original models proposed in 1963 (RFI1963; RLWG1963); a French model which included ultrasound measures of muscle and fat depth (RFIF) and the use of the Australian feeding standards to calculate predicted intake and thus RFI (RFISCA). Using feed intake, liveweight and body composition data generated from the same group of sheep (n = 52) at two ages (6 mo, 13 mo), the relative merits of each model were evaluated and compared to the other models, to determine the most appropriate model to calculate RFI for sheep. For all the models except that used to calculate RLWG, over half of the variation in FI could be explained by the model. The amount of variation in FI accounted for depended on the parameters included and the dataset, with less variation in FI explained by the specific models in the older animals. The RFIF model, which included measures of body composition, accounted for the greatest proportion of the variation in FI and as such suggests that the inclusion of body composition parameters is likely to more accurately reflect true biological efficiency.

The Cornell Net Carbohydrate and Protein System (CNCPS) predicts cattle requirements and nutrient supply for site-specific situations. This paper describes the CNCPS version 6 (CNCPSv6), which represents a re-engineering and updating of CNCPS version 5 with the following objectives: (1) improve the organization of the model and user interface to improve speed and accuracy in formulating diets for a herd of dairy cattle, (2) expand the carbohydrate pools to include sugars, soluble fibers, and organic and volatile fatty acids, (3) integrate a fat model to account for ruminal lypolization and biohydrogenation, and absorption of fatty acids in the small intestine, and (4) update the computational sub-models with new information. The CNCPSv6 model was re-designed using object-oriented programming in which physiological functions (e.g. growth, lactation, pregnancy) and anatomical compartments (e.g. rumen, intestines) were programmed as objects. The interface uses farm, location, and group flow, which decreases the number of inputs required per cattle group and allows for more rapid evaluation of diets, feed requirements, and nutrient excretion by location, group, and herd. The revised implementation of the body reserves sub-model allows accounting for fluxes in energy reserves when formulating diets. Updated equations and coefficients include the prediction of rumen ammonia balance and feed passage rates, indigestible DM, MP lactation efficiency, and DMI. The CNCPSv6 was evaluated with data from individually fed lactating dairy cows from three independent studies. As implemented, CNCPSv6 accounted for a similar proportion of the variation (86%) in first limiting (ME or MP) milk production as CNCPSv5 but with a lower bias (1% versus 4%, respectively). We concluded the re-designing and updating of the CNCPS improved its ability to formulate and evaluate a feeding program for a herd of dairy cattle with greater accuracy and efficiency.

International audience; The INRA Growth Model (IGM) and the Davis Growth Model (DGM) are two dynamic mechanistic models developed to predict protein and fat deposition in growing cattle whatever the production system. Both models depend on animal genotype and age, metabolizable energy intake (MEI) and knowledge of previous growth. The aim of this paper was (i) to identify in which situations DGM and/or IGM provide reliable estimations of body protein and fat, (ii) to give insight on the improvements needed in each model and (iii) to discuss the usefulness of comparative analysis for improvement of mechanistic models. We performed a comparative analysis of DGM and IGM with three datasets from published experiments on Salers heifers, Angus-Hereford steers and Charolais bulls. Each model was fitted independently to each dataset. Both models gave accurate and precise predictions of body protein. They also performed well for body fat in Charolais bulls growing continuously. However, DGM tended to underestimate body fat deposition during feeding restriction periods with Salers heifers. This suggests that DGM overestimated heat production during periods of low MEI. IGM was not sensitive enough to MEI as it overestimates body fat at low MEI and it underestimates body fat at high MEI in Angus-Hereford steers. Presently, IGM does not take into account metabolizable energy concentration (MEC) of the diet and thus does not simulate different growth trajectories for same MEI but different MEC. These results suggest that model's structure and equations for protein accretion in DGM and IGM are valid. Future improvements will focus on prediction of heat production during feed restriction periods for DGM and on mathematical formulation of feed energy utilisation for fat synthesis in IGM in order to improve model sensitivity to MEI. Comparative analysis provides meaningful information on the models behaviour for further improvement of processes simulations.

Feeding cattle high-grain diets has brought concurrent problems with ruminal acidosis. Grain overload in feedlot cattle has gained the most attention because of its economic impact. In fact, ruminal acidosis is second only to respiratory diseases, in depressing animal performance and production efficiency. Much of the past research has focused on effects of antimicrobial compounds (such as monensin) on ruminal fermentation; they have become management tools to prevent or to control ruminal acidosis. Despite beneficial effects of such compounds, in 2002 the European Commission proposed to ban on antibiotic growth promotants including monensin. This legislation has important economic implications in production cost of beef. Several nutritional alternatives to monensin have been studied in vitro with diverse results. This paper provides an overview of research with organic acids (malate and fumarate) for beef cattle as a substitute for monensin. Although these organic acids may be considered as feed additives, more research is needed about the effects of malate and (or) fumarate on beef cattle performance. Dietary factors such as forage:concentrate ratio, and forage or cereal grain type may alter the response to these additives. In addition, appropriate timing for supplementing with malate or fumarate must be studied.

The Australian grazing industry has made progress towards meeting requirements of meat processors for heavier carcass weights. However, further increases in the year-round supply of large lean lambs carries increased and uncertain financial risk for farmers. This paper examines year-to-year variability of gross margins for production of very large lean lambs, in a range of different grazing environments, using the decision support tool GrassGro™. GrassGro was used to compare systems for finishing lambs at liveweights (LW) of 42, 52 or 62 kg in three districts in SE Australia where the annual rainfall pattern varied from summer-dominant (Glen Innes, NSW), to non-seasonal (Cowra, NSW), to winter dominant (Hamilton, Vic.). Achieving these high LW required use of large ewes (average LW at maturity of 60–72 kg) and the rearing of male lambs made cryptorchid. Gross margins over 20 years and year-to-year variation in gross margins were assessed. Simulations showed that carrying lambs to heavier LW increased gross margins in all districts at lower stocking rates, even in the absence of price premiums for heavy lambs. However, at higher stocking rates, fattening lambs to heavier LW reduced mean gross margins. Carrying heavier lambs without reducing the stocking rate always increased variability in gross margins from the enterprise, mainly due to increased variability in the amount of feed supplement required. This demonstrates that to improve reliability of production and profitability in the prime lamb industry, the pricing strategy, risks and management practices associated with each environment need to be considered. Computer simulation provides a way to evaluate and optimize the design of the supply chain while taking into account regional and seasonal variability in pasture supply.

Near-infrared spectroscopy (NIRS) is a relatively new technology in the determination of chemical constituents in compound (complete) feeds. The current paper reports on the application of NIRS to the measurement of dry matter (DM), crude protein (CP) and crude fat (CF) in wet diets for mink and the development of a calibration to predict these chemical constituents. In total, 287 typical wet mink feeds were collected from commercial mink ranches located on the south shore of Nova Scotia, Canada, to provide a large representative sample population. After population structuring, using CENTER and SELECT software (ISI) during calibration development, there were 73 samples remaining in the calibration. All feeds were analyzed by standard reference methods (primary) and then scanned (secondary) with a scanning monochromator NIR, model 5000 (NIRSystems Inc.), to develop a global calibration to predict DM, CP and CF. The “best fit” treatment for the calibration was a modified partial least squares analysis with a standard normal variate (SNV) correction for scatter, a derivative math treatment of 1, 4, 4, 1 to remove particle size interference while scanning segments 1108–2492 skipping every 8 nm for prediction of DM, CP and CF. Standard error of calibration (SEC, g kg −1 ), proportion of explained variance (RSQ), and standard error of cross-validation (SECV, g kg −1 ) for DM, CP, and CF were; 11.9, 0.92 and 14.3; 11.3, 0.96 and 17.5; and 20.0, 0.92 and 22.5. Two external validation sets were used to evaluate the accuracy of the calibration with standard error of prediction (SEP), ranging from 12.7 to 19.5 g kg −1 . Based on the results of the data reported the use of NIRS technology in the nutritional evaluation of complete wet diets for mink is feasible. The most promising future use for this NIRS application is as on-line quality control in a central feed kitchen.

In recent years, ionophores (IOP) have been approved in several countries around the word for use in lactating dairy cows with claims for improved milk production and immune response. Currently, the use of IOP in lactating dairy cattle is not allowed in the USA, although the application for approval of monensin for use in these animals has been submitted. As a result, additional data from experiments in which IOP were administered to lactating dairy cattle have become available over the last few years. The objective of this paper is to review the current data regarding the effects of these compounds on milk production, health status, and reproductive performance of lactating dairy cows. In the rumen, IOP inhibit gram positive bacteria, which subsequently alter ruminal fermentation resulting in increased amounts of energy and N from feeds in forms usable by the cow. When administered at effective doses, IOP do not affect, or slightly decrease, feed intake by lactating cows. This effect combined with the IOP-mediated alterations in rumen fermentation increases the supply of nutrients, particularly propionate. As a result, the energy balance is improved, enhancing in turn milk production, efficiency of milk production, and immune response. The magnitude of these effects, however, appears to be determined by several factors, many of which are poorly understood. Based on available data, improved energy balance and its favorable effects on health and milk production would be primary benefits of administering IOP to lactating cows. Thus, periparturient dairy cows, particularly over-conditioned cows, may benefit the most from the use of IOP. However, the development of efficient implementation strategies that maximize the economic returns will depend on a better understanding of the effects of IOP on the metabolism, performance, and health of transition and lactating dairy cattle.

Browse plants play an important role in providing fodder for ruminants in most parts of the World. However, the presence of tannins and other phenolic compounds in a large number of these feed resources limits their utilization as animal feed. This paper presents the nutritive value of some browse species based on their chemical composition (nitrogen, polyphenolics and neutral detergent fibre (NDF) content), dry matter (DM) degradability in sacco and gas production in vitro including the effect of the phenolic binding compound, polyethyleneglycol-4000 (PEG 4000), on in vitro gas production. The browse species evaluated were Calluna vulgaris (heather), Sarothamnus scoparius (broom), Ulex europaeus (gorse) and Chamaecytisus palmensis (tagasaste). The crude protein (CP) content was highest (P < 0.05) in broom (189 g kg−1 DM) followed by tagasaste (175 g kg−1 DM) and gorse pre-flower (168 g kg−1 DM) and the lowest was in heather (98 g kg−1). Heather had the highest (P < 0.05) concentration of the phenolic compounds compared with all the other species. Gorse in-flower contained a higher concentration (P < 0.05) of total extractable phenols (TEPH), total extractable tannins (TETa) and NDF and a lower content of CP than gorse pre-flower which is a reflection of their stage of maturity. As a result, gorse pre-flower had a higher in sacco degradability and in vitro gas production than gorse in-flower. Heather had the lowest degradability values. The ranking order of the browse plants in gas production was gorse pre-flower > tagasaste > broom > gorse in-flower > heather which was similar to their in sacco degradability values. Increasing the amount of substrate incubated slightly depressed the amount of gas produced by the browse plants. The response to PEG treatment increased with increased concentration of phenolic compounds in the browse plants. Thus, in heather, gas production increased by 51% at 12 h of incubation as a result of PEG treatment while the response was zero in the species with a low content of phenolic compounds. The results show that the phenolic compounds depress in vitro gas production and that PEG treatment has a potential for improving gas production and fermentation of feedstuffs high in phenolics due to the binding of the phenolic compounds to the PEG.

The most widely used external indicator for feed intake evaluation of grazing animals is Cr 2 O 3 . In this paper the combination of Cr 2 O 3 dissolution by alkali fusion (Na 2 O 2 ) with its determination by atomic absorption spectrophotometry (AAS) has been examined. Faecal samples were collected from four 2-year-old, meat-type, female, local goats grazing in a Mediterranean type shrubland in Northern Greece, for 5 consecutive days. Each composited sample from every animal and day was analysed eight times. There was very high linear correlation ( Y = 0.0024 + 0.01 X , r 2 = 0.99) between absorbance ( Y ) (357.9 nm wavelength, 0.2 nm slit width) and Cr 2 O 3 concentration ( X ). The repeatability and reproducibility of the method was very satisfactory (CV ranged from 2.7 to 7.6%). The proposed method seems to be simple, inexpensive and precise for routine determination of Cr 2 O 3 in faeces of grazing animals in which Cr 2 O 3 is used as a reference marker.

The following paper discusses the impact of four specific trace elements—copper, zinc, selenium and manganese-on production and health parameters of grazing cattle. Typically in the cattle industry the greatest impairment of marginal trace element deficiencies may be on immune function, but in cases of severe deficiencies production traits such as reproduction efficiency and other performance parameters can be impacted. It is important that the diet formulation for trace minerals consider the forage intake, the forage trace mineral content and the animal's requirements and then dietary levels fed to meet animal requirements just as is typically done for nutrients such as energy and protein. Although minerals and trace elements have not received the degree of attention that energy and protein have in formulating grazing cattle diets, their potential impact on productivity should not be ignored.

The strong negative relationship between body weight and reproductive efficiency in broiler parent stocks has necessitated the management practice of feed restriction. There is relatively little known about how feed restriction impacts on reproduction in terms of gonadal form and function. This paper is a review of four experiments conducted with female and male commercial broiler breeders to further define the consequences of excessive feed allocation. In one study, hens were full-fed or feed restricted to typical industry target weights during the period from 22 to 62 weeks of age. It was observed that ad libitum feeding resulted in an increase in body weight of approximately 700 g and a reduction in egg production of 40 eggs. A further study was carried out as a 2 × 2 factorial design of full feeding vs. feed restriction during rearing and lay. The greater the duration of ad libitum feeding, the lower was the rate of egg production and the higher the incidence of multiple-yolked eggs, erratic lay and shell quality problems. Fertility and hatchability were significantly reduced with full feeding. Full-fed hens had an increased number of large ovarian follicles, and it is thought that the existence of partial or complete double or in some cases triple hierarchies resulted in an impairment of the normal control of the ovulatory cycle. In a third study, it was observed that the number of large follicles increased from 5.3 to 7.0 follicles in response to 14 days of ad libitum feeding. It is obvious that the loss of regulation of the ovarian hierarchy associated with over feeding can occur in a short period of time. The consequences of the ad libitum feeding of caged male broiler breeders during the period from 22 to 30 weeks of age was studied. The full-fed males gained almost 1 kg of body weight during the first week of full feeding. Dissection of some carcasses at 30 weeks of age revealed that breast muscle weight and fat pad weight were significantly greater in full-fed birds than in feed-restricted birds. The number of males in semen production early in the adult period (26 to 30 weeks of age) was numerically higher for the full-fed birds. The converse was true at the later stages of semen production. The benefits of controlling body weight in males early in the breeding period are evident much later at the end of the breeding period.

Field application of new feeding methods, such as urea ammonia treatment of straws requires an ex-ante assessment of their economic feasibility. Animal experiments are expensive for such an analysis, therefore cheaper and quicker methods are required. One such method is least cost ration formulation (LCRF), which extrapolates from a restricted number of feeding trials to a large number of feed combinations. The assumptions underlying LCRF can, however, be challenged and this paper discusses their validity in nutritional terms. The first part reviews literature on nutritive quality of rice straw, in relation to nutrient requirements and animal performance on rice straw based diets. The second part calculates the expected performances (Pcalc) on straw based rations, using measured dry matter intake (DMI) and estimated total digestible nitrogen (TDN) and crude protein (CP) values. It then comparesPcalc with real performance (Preal) as found in the literature. Most dose response trials indicate a rather linear response to supplementation, with exceptions particularly at low levels of supplementation. The pooled values ofPcalc relate linearly withPreal in several feeding trials. ThePcalc only comes close toPreal when calculated on a TDN basis, when energy requirements for liveweight gain of light tropical animals are taken to be higher than those of NRC and when digestibility of energy in straws is assumed to be low. This suggests a low utilisation of digestible energy from either treated or untreated straw for reasons that cannot easily be established. Total CP supply cannot be limiting because thePcalc on the basis of CP also considerably overestimatesPreal. The available literature values do not allow specification of CP into fractions according to rumen degradability. At production levels around maintenance, the correlation betweenPreal andPcalc decreases, possibly because at those levels the variability of maintenance requirements exerts a bigger effect on the total performance. Also, at those levels, straw constitutes a larger part of the ration, and associative effects are more likely. The sparse literature values for milk production also indicate differences betweenPreal andPcalc. The conclusions are that, in the absence of better methods, LCRF can be useful for ranking purposes but absolute values need to be interpreted with care, andPcalc tends to overestimatePreal. Future performance trials should measure digestible organic matter intake, substitution rates and maintenance requirements by dose response curves in order to improve their predictive value, and to allow interpretation of differences betweenPreal andPcalc. Differences betweenPreal andPcalc can then be investigated and weighed against accuracy and cost of performance trials.

In vitro and in sacco methods for estimation of dietary protein degradability in the rumen are reviewed. Several variables associated with in sacco experimentation were evaluated and recommended guidelines were proposed: bag porosity must be large enough for the degradation process to take place normally inside the bag and sufficiently small to limit losses of undegraded fine particles; fineness of grinding sample must mimic the effect of mastication; it must be defined not by the grinding screen aperture, but by the mean particulate size; other variables were studied as sample size to bag surface ratio, bag incubation sequence, relative location of nylon bag within the rumen and explanations for variations were proposed. Microbial contamination of bag residues and modelling of nitrogen degradation kinetics were the subjects of recent publications and are discussed in this paper. The variability of results were studied and recommendations (use of standard feed) were made to limit the variations.

A wet-fractionation process was applied to foliage (shoots < 0.5 cm in diameter), twigs, leaves and pods of Sophora japonica L. to obtain press cake and juice or protein concentrate for feeding purposes and, simultaneously, other organic substances for industrial, medical or pharmaceutical use. This paper gives the first results for yields and composition of the original biomass (OB), and of the press cake (PC), green juice (GJ), leaf-protein concentrate (LPC) and soluble concentrate (SC). The dry matter (DM) extraction ratio was 30% in the GJ. From 1000 kg of initial fresh biomass the DM in the LPC was 42 kg and the yield of crude protein (CP) in the LPC reached 6.7 kg. Both OB and PC had high DM contents (32.0 and 31.8% respectively). Neutral detergent fibre (NDF) and acid detergent fibre (ADF) were low (39.0 and 30.8%, respectively) in the DM of PC. Total nitrogen, non-protein nitrogen (NPN), nitric nitrogen and crude ash were 9, 28, 71 and 20% lower, respectively and NDF and ADF were 27% higher, in the PC as compared with the OB dry matter. Relatively high proportions of NDF (6.1%) and ADF (4.4%) were detected in the GJ dry matter, which also had a high content (10.1%) of ether extract (EE). The CP content in the DM of LPC was very low (15.9%). On the other hand, EE (18.0%) and, in particular, total lipids (which amounted to 69% of the DM) were very high. Total carotenoids, carotene and xanthophylls contents in DM of LPC were also low (299.2, 52.1 and 216.6 mg kg−1, respectively); lutein (138.2 mg kg−1) represented more than half of the total xanthophylls. Total polyphenols in the biomass amounted to 11.0% (in LPC 13.6%), these being mainly free polyphenols (9.8 and 12.1%, respectively). Some previous data on the composition of LPC lipidic fractions are also given.