The use of mid-infrared spectrometry to estimate the ration composition of lactating dairy cows

The composition of cow milk is strongly affected by the feeding regimen. Because milk components are routinely determined using mid-infrared (MIR) spectrometry, MIR spectra could also be used to estimate an animal’s ration composition. The objective of this study was to determine whether and how well amounts of dry matter intake and the proportions of concentrates, hay, grass silage, maize silage, and pasture in the total ration can be estimated using MIR spectra at an individual animal level. A total of 10,200 milk samples and sets of feed intake data were collected from 90 dairy cows at 2 experimental farms of the Agricultural Research and Education Centre in Raumberg-Gumpenstein, Austria. For each run of analysis, the data set was split into a calibration and a validation data set in a 40:60 ratio. Estimated ration compositions were calculated using a partial least squares regression and then compared with the respective observed ration compositions. In separate analyses, the factors milk yield and concentrate intake were included as additional predictors. To evaluate accuracy, the coefficient of determination (R2) and ratio to performance deviation were used. The highest R2 values (for kg of dry matter intake/ for % of ration) for the individual feedstuffs were as follows: pasture, 0.63/0.66; grass silage, 0.32/0.43; concentrate intake, 0.39/0.34; maize silage, 0.32/0.33; and hay, 0.15/0.16. Estimation of groups of feedstuffs (forages, energy-dense feedstuffs) mostly resulted in R2 values >0.50. Including the parameters milk yield or concentrate intake improved R2 values by up to 0.21, with an average improvement of 0.04. The results of this study indicate that not all ration components may be estimated equally accurately. Even if some estimates are good on average, there may be strong deviations between estimated and observed values in individual data sets, and therefore individual estimates should not be overemphasized. Further research including pooled samples (e.g., bulk milk, farm samples) or variations in ration composition is called for

Potenzial der Mid-Infrarot-Spektrometrie bei Kuhmilchproben zur Abschätzung der Rationszusammensetzung

Milk composition of dairy animals is influenced by the composition of the ration fed. The objective of this study was to determine if the percentages and absolute amounts of hay, grass silage, pasture, maize silage and concentrate in the feed ration can be estimated using MIR spectrometry of milk. A total of 10200 milk samples from 90 dairy cows were collected, and the intakes of all ration components were measured. Using partial least squares regression (PLS), equations were developed to estimate ration compositions corresponding to each milk sample. To evaluate accuracy, the correlation between observed and estimated values (R) and ratio to performance (RPD) were used. Notable R values (for kg/for %) were observed for the ration proportion of pasture (0.85/0.87), maize silage (0.74/0.75) and concentrate intake (0.75/0.73). Estimation of groups of feedstuffs (all forages, energy-dense feedstuffs) resulted in R values of >0.8. Including the parameters milk yield and/or concentrate intake into PLS improved R values by up to 0.08. The results indicate a potential use of MIR spectra as a promising predictor for ration composition of dairy cows

Replacing concentrates with a high-quality hay in the starter feed of dairy calves: II. Effects on the development of chewing and gut fermentation, and selected systemic health variables

Early development of the rumen, rumination and fermentation is highly important in dairy calves. Yet, common rearing practices with feeding of concentrate-rich starters may jeopardize them because of lacking physically effective fiber (peNDF). The main objective of this study was to establish the influence of the composition of the calf starter feed (only forage with two different qualities or concentrate-rich starter diet) on chewing behaviour, rumen development, rumen and hindgut fermentation, and selected systemic health and stress variables of dairy calves. The experiment was carried out with 40 newborn Holstein-Friesian calves, randomly assigned to four different solid feed treatments: MQH = 100% medium-quality hay (9.4 MJ ME, 149 g CP, 522 g NDF/kg DM), HQH = 100% high-quality hay (11.2 MJ ME, 210 g CP, 455 g NDF/kg DM), MQH+C = 30% MQH + 70% starter concentrate, HQH+C = 30% HQH + 70% starter concentrate). All calves were up to 14 wk in the trial and received acidified whole milk ad libitum in the first 4 wk of life, thereafter in reduced quantity until weaning on 12 wk of age. Water and the solid feed treatments were available ad libitum throughout the trial. Chewing activity was measured in wk 4, 6, 10, and 12 using Rumiwatch halters. Until wk 3, rumen fluid, feces and blood were sampled weekly, thereafter every 2 wk. Rumen mucosal thickness (RMT) was measured on the same days with rumen fluid samples. Data show daily variation in eating and ruminating activity and proportion of certain SCFA in total SCFA in rumen fluid and feces of calves offered different feed treatments.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Replacing concentrates with a high-quality hay in the starter feed in dairy calves: Effects on nutrient intake, growth performance, and blood metabolic profile

Feeding concentrate-rich starter feeds to dairy calves increases the risk of ruminal acidosis due to a low concentration of structural fiber. In this study, we hypothesized that feeding high quality hay can be a strategy to overcome this risk while maintainig adequate supply with energy and protein. Therefore we examined nutrient intake, daily gain and concentration of metabolites in blood of calves from birth to week 14 of life. Calves were offered acidified milk till week 12 of life according to a defined milk feeding scheme and water throughout the whole experiment. Furthermore, calves wer fed one of four experimental diets (solid feeds) throughout the whole experiment: 100 % medium quality hay, 100 % high quality hay, 30 % medium quality hay + 70 % concentrates and 30 % high quality hay + 70 % concentrates.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV