In vitro degradability, gas production, and energy value of different hybrids of sorghum after storage in mini-silos

Abstract This experiment compared silages obtained from 3 hybrids of sorghum grown on 2 farms of the Po Valley (one irrigated and one not), in terms of in vitro degradability, gas production (GP), and energy value. Hybrids (forage, sweet or grain genotypes) were sown in experimental plots (3 plots × 3 hybrids), harvested at late-milk stage of maturity, and ensiled into mini-silos (3 silos × 3 hybrids) for 60 d. After ensiling, silages were analyzed for composition and fermentation profile. Two incubations (at 48 h) were carried out to measure NDF degradability (NDFd), GP, and the metabolizable energy (ME) content of silages. Data of silage composition were submitted to ANOVA, considering farm (F), hybrid (H), and F × H interaction as variation sources. Incubation (run) was also considered as a fixed effect in the statistical model for the parameters obtained by in vitro incubation (NDFd, GP, and energy content). On the irrigated farm (Farm 2), the DM contents of silages were higher than those of the non-irrigated one (P&lt;0.001) and the fermentation profile was more favorable. Values of GP at 24 and 48 h and ME content were higher (P&lt;0.05) for silages of Farm 2 in comparison with Farm 1. Within hybrids, the grain sorghum revealed the greatest DM content whereas the forage sorghum, as expected, was the richest in fibrous fraction content, followed by the sweet and grain genotypes (P&lt;0.001). Consequently, values of GP were significantly (P&lt;0.01) influenced by hybrid (167, 200, 215 ml/g DM and 229, 257, 267 ml/g DM for forage, sweet and grain genotypes after 24 and 48 h of incubation, respectively). The F × H interaction was significant for all considered parameters excluding DM, lignin, ash, pH, and in vitro parameters. On the two farms, in general, forage and grain genotypes were largely different, whereas the sweet sorghum was quite similar to the forage in one case or grain in the other. Results of this experiment highlight the large variability of the nutritional values of sorghum hybrids grown in different conditions.</jats:p

Effect of Pressing and Combination of Three Storage Temperatures and Times on Chemical Composition and Fatty Acid Profile of Canola Expellers

This experiment investigated the effects of combinations of three temperatures and storage times on chemical composition, fatty acid profile, and oxidative stability of canola expellers obtained from the cold-pressing extraction of oil. Canola seeds were single-crushed at moderate temperatures (60°C) during 3 pressing sessions. Nine samples (100±1 g) of each session were collected, inserted into sealed bags, stored at three temperatures (12, 24, 36°C) over 3 periods of time (10, 20, 30 d). Then, samples (100±1 g) of canola seeds collected before each pressing session and canola expellers collected before and after each storage time were analyzed for chemical composition, fatty acid profile, peroxide number and Kreis test. Before storage, the fatty acid profile of canola seeds and expellers differed significantly, except for myristic (P=0.18), palmitic (P=0.57), oleic (P=0.07), and α-linolenic acids (P=0.45). Compared to canola seeds, expellers showed greater content of saturated, poly-unsaturated, and n-6 fatty acids (P<0.01), but a lower content of mono-unsaturated fatty acids (P<0.01). Peroxide values were definitely (P<0.01) greater for expellers and averaged 4.22 and 4.11 mEq/kg fat before and after storage, respectively. The Kreis test was negative for all samples. Under different temperatures and times of storage, canola expellers showed to maintain a good oxidative stability, as highlighted by low peroxide values (<10 mEq/kg fat) and negative response for Kreis test. Canola expellers obtained by on-farm cold extraction, despite great oil residual (from 17 to 19% ether extracts on dry matter basis), can be stored at farm without significant chemical and nutritional changes

Organic farming of dairy goats in the Veneto region: feeding management and milk quality

The relationship between the quality of goat milk and the feeding management in organic farms located in the Veneto Region was evaluated. Five organic dairy goat farms with Alpine and Saanen breeds were considered. Samples of bulk milk and feeds were collected monthly and analysed for chemical composition. Milk fatty acids profile was also determined. All data were submitted by ANCOVA analysis using breed (B), time of sampling (ST) and B x ST as fixed effects and dry matter intake (DMI), dietary concentrations of crude protein (CPc), NDF (NDFc), starch (starchc), and use of grazing as linear covariates. Milk urea N was positively affected by DMI (r=3.64; P<0.05) and negatively by starchc (r=-5.91; P<0.05) and total bacterial count increased significantly (P<0.05) with the increase of CPc and starchc. DMI affected positively the milk fatty acid (FA) profile by increasing of PUFA (P<0.01), n-3 (P<0.001) and n-6 (P<0.05) acids and decreasing of SFA (P<0.05) levels in milk. Opposite effects on FA profile were observed by CPc, NDFc and starchc. The use of grazing only caused a significant increase (P<0.05) in the content of CLA in milk

Methodological factors affecting gas and methane production during in vitro rumen fermentation evaluated by meta-analysis approach

Effects of some methodological factors on in vitro measures of gas production (GP, mL/g DM), CH4 production (mL/g DM) and proportion (% CH4 on total GP) were investigated by meta-analysis. These factors were considered: pressure in the GP equipment (0 = constant; 1 = increasing), incubation time (0 = 24; 1 = 65 48 h), time of rumen fluid collection (0 = before feeding; 1 = after feeding of donor animals), donor species of rumen fluid (0 = sheep; 1 = bovine), presence of N in the buffer solution (0 = presence; 1 = absence), and ratio between amount of buffered rumen fluid and feed sample (BRF/FS; 0 = 64 130 mL/g DM; 1 = 130\u2013140 mL/g DM; 2 = 65 140 mL/g DM). The NDF content of feed sample incubated (NDF) was considered as a continuous variable. From an initial database of 105 papers, 58 were discarded because one of the above-mentioned factors was not stated. After discarding 17 papers, the final dataset comprised 30 papers (339 observations). A preliminary mixed model analysis was carried out on experimental data considering the study as random factor. Variables adjusted for study effect were analyzed using a backward stepwise analysis including the above-mentioned variables. The analysis showed that the extension of incubation time and reduction of NDF increased GP and CH4 values. Values of GP and CH4 also increased when rumen fluid was collected after feeding compared to before feeding (+26.4 and +9.0 mL/g DM, for GP and CH4), from bovine compared to sheep (+32.8 and +5.2 mL/g DM, for GP and CH4), and when the buffer solution did not contain N (+24.7 and +6.7 mL/g DM for GP and CH4). The increase of BRF/FS ratio enhanced GP and CH4 production (+7.7 and +3.3 mL/g DM per each class of increase, respectively). In vitro techniques for measuring GP and CH4 production are mostly used as screening methods, thus a full standardization of such techniques is not feasible. However, a greater harmonization of analytical procedures (i.e., a reduction in the number of available protocols) would be useful to facilitate comparison between results of different experiments

Changes of particle size distribution and chemical composition of a hay-based ration offered once or twice daily to dairy cows

The objective of this experiment is to evaluate the changes of particle size distribution and chemical composition of the total mixed ration (TMR) based on hay as the main forage component ("dry" TMR) and distributed once (7.00 am) or twice (7.00 am and 1.00 pm) daily to 32 lactating cows. The trial was divided in two periods of 14 days each. Diet (DM=53.7%) was formulated in order to assure the nutritional requirements of cows producing 24 kg/d of milk (crude protein=14.4% DM; NDF=40.9% DM; milk FU=0.88/kg DM) and additional amounts of concentrates were distributed using automatic feeders. Four TMR samples were collected daily (7.00 am, 10.00 am, 1.00 pm, 4.00 pm) for six days during each experiment period for a total number of 48 feed samples. Each feed sample was subjected to the estimation of the particle size distribution using the separator of Pennsylvania State University composed of two sieves (diameters of 19 and 8 mm) and a collector on the bottom, and to the determination of the chemical composition. Changes of all three particle size fractions for TMRs were observed during the day with distributions of the TMR both once and twice daily. With the once daily distribution, the large particles fraction increased linearly (P<0.001) from 19.7 to 23.4, 32.2, and 35.1%, while the finest particle fraction decreased (from 60.1 to 58.3, 50.0, 47.8%). According to particle size changes, the chemical composition varied significantly at the different times of sampling when TMR was distributed once daily. Significant variations of DM were detected for TMR with a linear (P<0.001) increase (from 54.4 to 57.9, 60.7, 61.5%). Considering once TMR distribution, the values of NDF and starch showed an opposite trend with an increase of 6.5 and a decrease of 8.3 points from 7.00 am to 4.00 pm (i.e., 9 hrs after distribution). Correlations were estimated between chemical and physical characteristics of TMRs. NDF content was positively and significantly correlated to the fraction of particles retained by a 19 mm sieve (r=0.42; P<0.001) and negatively correlated with the smaller particles (r=-0.51; P<0.001). In conclusion, when the TMRs are prepared excluding corn/hay silages, twice daily distributions of diet can avoid the selection of large feed by the cows, thereby preserving both a uniform particle size distribution and a steady chemical composition of the diet during the day. However, the cost for the extra time needed for twice daily dis- tribution should be carefully considered

Evaluation of Behaviour in Stabled Draught Horse Foals Fed Diets With Two Protein Levels

The present work is aimed at evaluating the behaviour of Italian Heavy Draught Horse (IHDH) foals reared in semi-covered stables and fed two isoenergetic total mixed rations with different dietary protein levels (13.2% and 10.6% of CP on dry matter). The study was prompted by the restrictions for nitrate emissions in farms of the European Nitrate Directive. One suggested solution is to reduce dietary protein while maintaining normal performance and welfare, but there is a lack of literature in studies of horses. The behaviours of 20 foals of 437±60 kg of BW, aged 379±37 days and stabled in four pens by sex (S) and diet (D) were video recorded and analysed to build a suitable ethogram including 18 behaviours in six categories: ingestion, resting, maintenance, movement, social activities, other. The percentage of the daily time spent in each behavioural category and single behaviours was analysed via a single traits GLM including S, D and their interaction. Daily activity was consistent with existing literature: foals spent about 33% of the day in ingestion activities and 41% in resting, whereas social interactions constituted 8% of the time and individual maintenance <2%. Concerning diet, foals fed high protein spent more time in movement (19.62±0.73% of day v. 10.45±0.73% in low-protein (LP) foals; P⩽0.001), whereas the LP group increased resting (43.42±1.12% v. 38.02±1.12%; P⩽0.001). No stereotypies were found, and daily activity followed the typical values for draught breeds for foals in both dietary groups, a result that suggests the maintenance of well-being after dietary protein reduction. This result, together with the findings of a companion study showing no changes in growth performances of foals, showed that a reduction of CP in foal diet is reconcilable with the maintenance of performance and welfare

Effects of sugar beet pulp on growth and health status of weaned piglets

The effects on growth performance and on some health parameters due to the inclusion of sugar beet pulp in antibioticfreediets for weaned piglets were evaluated on a commercial farm. A conventional diet (C) and one containing 120 g/kgof sugar beet pulp (SBP) were fed to 668 weaned piglets from 21 to 64±3 days of age. Every two weeks, live weight andfeed consumption (FC) of the two groups were recorded by pens. Fecal samples were collected from 8 pairs of piglets foreach treatment to evaluate the evolution over the time of the apparent digestibility of the nutrients, as well as the volatilefatty acids content and the microbial count in the feces. The dietary treatment did not affect FC. In comparison to C, SBPslightly reduced average daily gain over 36 to 49 (528 vs. 498 g/d; P<0.05) and 50 to 64±3 (677 vs. 631 g/d, respectively;P<0.01) days of age. Digestibility of NDF of diet C increased with age from 441 to 526 g/kg whereas that of dietSBP increased from 465 to 638 g/kg. The differences between diets became significant after 36 days of age (P<0.01).From 29 to 35 days of age higher contents of water (793 vs. 713 g/kg; P<0.01), acetic (322 vs. 206 μmol/g dm; P<0.01)propionic (108 vs. 81 μmol/kg dm; P<0.01) acids and lower counts for fecal-coliforms (6.9 vs. 8.2 log10/g; P<0.01),clostridia (1.3 vs. 2.3 log10/g; P<0.01) and Staphylococcus spp. (6.7 vs. 8.1 log10/g; P<0.01) were found in the feces ofthe SBP piglets compared to those of C. These differences progressively disappeared with time. Some piglets showedclinical signs of purulent arthritis and meningitis, but no signs of diarrhea were observed. The SBP group showed, withrespect to C, a significantly lower number of piglet deaths caused by meningitis (15 vs. 30 ‰, respectively; χ2, P<0.05),and a significantly lower number of piglets removed because lack of growth (33 vs. 76 ‰, respectively; χ2, P<0.01). Noclear evidence to explain this result was found, however it was concluded that the inclusion of 12% of sugar beet pulpin antibiotic-free diets can improve the health status of piglets with little effect on growth performance

Omission of dry period and effects on the subsequent lactation curve and on milk quality around calving in Italian Holstein cows

The aim of this study was to investigate the effect of dry period omission on subsequent milk production over a whole lactation and the effect on milk quality around calving. Seventeen Italian Friesian cows, homogeneous for milk yield and parity, were managed either with a traditional dry-off period of 55d (CTR group; n=8) or continuously milked up to parturition (CON group; n=9). Milk yield was recorded daily from 75±7 d before expected calving date to the end of subsequent lactation to fit the lactation curve. Before parturition milk samples were collected at -70 d, -60 d, and -55 d for CTR and CON groups and at -40 d, -30 d, and -7 d for CON cows. After calving, six milk samples were taken from 1d to 90 d from both groups and analyzed for fat, protein, lactose, MUN and somatic cells. Body weight (BW) and body condition (BCS) were obtained 7 times from -55 d before expected calving to 90 d after calving. The omission of the dry period modified the shape of lactation in CON cows that reached the peak 10 d earlier and producing - 5.5 kg/d than CTR. Over a 305 d period, the milk yield reduction was of -2241 kg in CON group. The higher amount of milk produced before calving, i.e., 560 kg of milk in 52 d of mean pre-partum period, did not compensate the milk yield reduction after a continuous lactation. Milk quality was unaffected by the omission of dry period after calving, and animals in both lactation groups showed a similar decreasing trends over time for fat and protein, and increasing trends for lactose and MUN. Somatic cell score remained higher (4.54 vs 3.40) in CON than in CTR cows after calving. No different BW or BCS changes were observed for both groups after calving. We conclude that despite the absence of great differences in milk quality, the complete omission of the dry period in cows reduce significantly the milk yield, suggesting no economical benefit from this management strategy