Short communication: The relationship between dietary particle size and undegraded neutral detergent fibre in lactating dairy cows: A prospective cohort observational study

Abstract Physically effective NDF (peNDF) and undegraded aNDF at 240 h (uNDF.240) are important parameters for characterizing NDF in fibre evaluation and are associated with dietary physical form and fibre digestibility characteristics. A new concept that combines peNDF and uNDF.240, physically effective uNDF.240 (peuNDF.240 = pef × uNDF.240), was recently established. The peuNDF.240 value allows determination of dry matter intake (DMI), and the productive response of cows even in the absence of variation in DMI or when cows are fed rations with low uNDF.240 and high peNDF or rations with high uNDF.240 and more finely chopped fibre. The aim of this study was to improve our understanding of the relationships between dietary uNDF.240 content to other fibre fractions, average cow DMI, gross feed efficiency, and milk yield at the farm level. Furthermore, the relation between peuNDF.240 and the productive response of cows was also investigated at the farm level. In the Po' Valley, which is a representative area for dairy production in Italy, a cohort of 22 Holstein dairy farms was monitored over two years (2019–2020). Information regarding average cow DMI, milk yield, and ration composition was obtained through interviews with farmers, and feed samples were collected and chemically analysed. Farms were classified according to their dietary uNDF.240 (% of DM) content: low (uL) ≤ 8.29 or high (uH) > 8.29. Farms with low dietary uNDF.240 used less alfalfa forage as a fibre source compared with farms with high dietary uNDF.240 (6.27 vs. 15.5 % of DM) and showed higher average milk yield (35.9 vs. 33.6 kg/cow/day, respectively) and similar DMI (23.9 vs. 24.3 kg/cow/day, respectively). Dietary peuNDF.240 was negatively related to milk yield (milk yield = 47.4 – 1.87 peuNDF.240, R2 = 0.62, adjusted R2 = 0.60, residual standard error (RSE) = 1.87, P = 0.001) and gross feed efficiency (gross feed efficiency = 1.96 – 0.08 peuNDF.240, R2 = 0.65, adjusted R2 = 0.64, RSE = 0.07, P = 0.001). The results of this study have practical significance for farmers, as they suggest that the inclusion of low digestible forages in the ration (i.e., late-harvested alfalfa characterized by high uNDF.240) may require more fine shredding to reduce the overall value of peuNDF.240 and increase cow production

Near infrared calibration transfer for undried whole maize plant between laboratory and on-site spectrometers

The analysis of the maize plant immediately after harvest is essential in order to check the composition and maturity of the plant to optimise the quality of silage. NIRS calibrations were carried out on chopped maize using three spectrophotometers: a laboratory instrument (FOSS NIRSystems 5000 scanning monochromator, FOSS, Silver Spring, MD) and two versions of newgeneration portable instruments (poliSPECNIR, PL1 and PL2). The aim was to verify the quality of the transfer of the calibration curves between FOSS, PL1 and PL2 and between PL1 and PL2, obtained by three methods of spectra processing: pre-processing, piecewise direct standardisation (PDS) and direct standardisation (DS). Seventy-six samples of chopped whole maize plant were scanned with the three instruments and were analysed by wet chemistry for dry matter (DM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), starch and total sugars, to develop calibration equations. Two more datasets of 15 samples each were used for the standardisation of equations and validation. The calibration transfer obtained, according to the values of R2, standard error of prediction and bias, can be considered satisfactory (0.72>R2<0.97) for DM, ash and NDF for both poliSPECNIR, while CP and ADF have shown a good accuracy of prediction (0.78>R2<0.82) with PL2. Using FOSS as a master instrument, the choice of method of standardisation varies depending on the slave instrument even though the best results are obtained using PDS with PL2. The most accurate predictions are reached using PDS even when PL1 is the master

Prediction performances of portable near infrared instruments for at farm forage analysis

The objective of this study was to evaluate the use of Near Infrared Spectroscopy (NIRS) to analyze maize silage with a portable instrument. The instrument was a Zeiss Corona 45 working between 960 and 1700 nm which was used in Italy, Czech Republic and Poland. Best prediction performances were obtained using the Italian data set. Prediction error were 1.0, 0.16 and 0.4 respectively for DM, CP and NDF on a as is basis. With the instrument from Poland and Czech Republic there were lower accuracy of prediction compared to the Italian dataset, probably for their limited (less than 100 samples) calibration data set. Merging all the data set improved prediction accuracy for CP but not DM. It would appear that some form of instrument standardization is needed before merging data set

Research Note: Effect of chicken genotype and white striping–wooden breast condition on breast meat proximate composition and amino acid profile

The present experiment compared the proximate composition, the amino acid content, and profile of the breast meat of a commercial broiler hybrid (Hybrid-Normal) vs. a broiler hybrid affected by the simultaneous presence of white striping (WS) and wooden breast (WB) myopathies (Hybrid-WSWB) vs. the Italian purebred Polverara chicken (Polverara). To this purpose, a total of n = 30 breast meat cuts from male chickens/group were subjected to meat quality evaluations. Chickens were slaughtered at their commercial age. The meat of the Polverara breed showed the highest protein (P < 0.0001) and the lowest lipids (P < 0.0001) contents, whereas that of the Hybrid-WSWB broiler chickens had the lowest protein and ash (P < 0.0001) contents and the highest (P < 0.0001) amount of fat. Meat of Hybrid-Normal chickens displayed intermediate values. Polverara meat was the richest in most amino acids (g/100 g meat), whereas Hybrid-WSWB one had the lowest content (P < 0.0001). Taurine was not detected in the meat of the Polverara chicken. The meat of Hybrid-Normal chickens was the richest in valine and taurine amino acids (P < 0.0001). Results on the amino acids proportions (% of total amino acids) highlighted that lysine, arginine, leucine, glutamic acid, aspartic acid, alanine, and serine were the most representative essential and nonessential amino acids, respectively, in all 3 meat-types chickens. The study confirmed that WS and WB myopathies negatively affect the meat proximate composition and the amino acid content. The meat of the Polverara breed displayed a remarkable meat quality including a high protein content of very good quality. This may represent a tool to promote its meat among consumers and help the survival of this endangered breed. Furthermore, research efforts should be conducted to understand why taurine was absent in the breast meat of Polverara chicken

Effects of axial and ceiling fans on environmental conditions, performance and rumination in beef cattle during the early fattening period

The aim of this study was to assess the effect of two air stirring systems (ceiling fans vs. axial fans) on environment, performance, rumination and activity of beef cattle during the first period after the arrival to the fattening unit. One group of 106 charolais bulls was raised from August to October in a roofed, loose housing facility with straw bedding. Animals were randomly assigned to pens equipped with one of two types of fans: ceiling fans and axial fans. The trial lasted 70 days, and was divided into 3 periods. In the first and third periods fans were in operation, whereas in the second they were switched off. Animals were evaluated for average daily weight gain, cleanliness, dry matter intake, rumination time, activity level and health condition. The temperature-humidity index and the comprehensive climate index were continuously calculated and pens were periodically checked for the dry matter of the bedding. The average temperature-humidity index was lower in the third period (65.5) compared to the first (74.4) and second (75.3) periods (P < 0.001), but was not affected by the air stirring system, while on the contrary the comprehensive climate index was higher in AF than in CF during the first period (27.1 vs. 24.9 °C; P < 0.05). Ceiling fans led to higher dry matter of the bedding in the first (30.6 vs. 45.1%; P < 0.01), second (29.4 vs. 34.3%; P < 0.05) and third periods (22.2 vs. 31.3%; P < 0.05) and to cleaner bulls at the end of the trial. Animals raised with ceiling fans showed higher average daily weight gain (1.20 vs. 1.36 kg/day; P = 0.039), higher daily rumination time in the first period (431 vs. 475 m; P < 0.01) and patterns of rumination and activity compatible with a lower level of heat stress. Based on these results, it appears that ceiling fans are promising tools to be used to reduce heat stress and optimize performance of beef cattle

Proposal and validation of new indexes to evaluate maize silage fermentative quality in lab-scale ensiling conditions through the use of a receiver operating characteristic analysis

In the context of dairy cow feeding, it is increasingly important to know the quality of the maize silage used in the ration and therefore, it appears to be crucial optimizing the techniques necessary to assess it. The aim of this study was to evaluate whether some reference indexes, like the Flieg-Zimmer's (FZS), the German agricultural society's (DLG) and Vanbelle's scores, could properly estimate the quality of fermentations of maize silage made in a lab-scale ensiling system, and to calculate and validate new quality indexes suitable for lab-scale fermentations. The experimental dataset was obtained by analysing through near-infrared spectroscopy 522 samples of whole maize crop ensiled immediately after the harvest, using the vacuum-packing technique. The six (I1 \u2013 I6) new indexes were calculated on the basis of chemical and physical parameters as: pH, organic acids, ethanol, etc. All the indexes were tested for normality with the Shapiro\u2013Wilk test. In order to define the accuracy with which the new indexes ranked the maize silage on the basis of its fermentation quality, a receiver operating characteristic (ROC) analysis was performed, using the FZS as gold standard test and dichotomizing the FZS in two levels according to a cut-off (FZS 360 g/kg) dry matter (DM). In the lab-scale silages the new indexes were normally distributed, whereas the reference indexes were not. The new indexes showed values of AUC ranging between 0.76 and 0.89, with the I5 index showing the best combination of sensitivity (0.87) and specificity (0.77) in discriminating between good and poor quality silage. The cut-off of the new indexes ranged between 45.0 and 57.4 points. The lab-scale silages were all excellent, no matter the category of DM. However, while FZS and DLG did not differ among the 3 categories, I1 \u2013 I6 were significantly higher in silages with low DM (P < 0.001). Silages with low DM had the highest concentrations of lactic acid (56.4 g/kg DM, P < 0.001), ammonia (61.4 g/kg DM, P < 0.001) and butyric acid (0.62 g/kg DM, P < 0.001) as well. Data confirmed that the new proposed indexes are promising in describing the fermentation quality of maize silage in lab-scale conditions

Assessment of chicken breast shelf life based on bench-top and portable near-infrared spectroscopy tools coupled with chemometrics

Abstract Objectives Near-infrared (NIR) spectroscopy is a rapid technique able to assess meat quality even if its capability to determine the shelf life of chicken fresh cuts is still debated, especially for portable devices. The aim of the study was to compare bench-top and portable NIR instruments in discriminating between four chicken breast refrigeration times (RT), coupled with multivariate classifier models. Materials and Methods Ninety-six samples were analysed by both NIR tools at 2, 6, 10 and 14 days post mortem. NIR data were subsequently submitted to partial least squares discriminant analysis (PLS-DA) and canonical discriminant analysis (CDA). The latter was preceded by double feature selection based on Boruta and Stepwise procedures. Results PLS-DA sorted moderate separation of RT theses, while shelf life assessment was more accurate on application of Stepwise-CDA. Bench-top tool had better performance than portable one, probably because it captured more informative spectral data as shown by the variable importance in projection (VIP) and restricted pool of Stepwise-CDA predictive scores (SPS). Conclusions NIR tools coupled with a multivariate model provide deep insight into the physicochemical processes occurring during storage. Spectroscopy showed reliable effectiveness to recognise a 7-day shelf life threshold of breasts, suitable for routine at-line application for screening of meat quality

Short Communication: Prognostic Values of a Multiparametric Risk Score in Maize Silage Undergoing Different Ensiling Conditions

We studied the effects of the use of Lactobacillus buchneri (Lb) and the maize pre-ensiling composition on the aerobic silage stability in a panel of 88 maize ensiled 60 days in 21 L buckets. Lb was dispensed at three dosages and compared to a control (pure water). The prognostic multiparametric risk score was used to find the risk factors related to the chemical composition of the fresh plant, associated with the onset of aerobic instability in maize silage. A multivariable Akaike’s Information Criterion in the backward Cox proportional hazard regression was estimated for pre-ensiled maize chemical traits. A Multiple Factorial Analysis (MFA) was calculated. The hazard ratios were 1.02, 1.34, 0.66, 0.65, 1.57, and 1.06 for dry matter (DM), crude protein (CP), ether extract (EE), aNDF, lignin (sulfuric acid, sa), and water-soluble carbohydrates (WSC), respectively (p < 0.05, DM, p = 0.15). At the MFA, ash, CP, aNDF, ADF, and lignin (sa) were grouped with a positive Dim-1, while DM, EE, and starch were grouped with a negative coordinate; WSC stood alone with Dim-1 close to zero. CP, EE, aNDF, lignin (sa), and WSC resulted in the most relevant traits and were used to build the nomogram. The use of strains of Lb improved the aerobic stability for maize harvested at <300 g/kg of DM