The relationships between early lactation energy status indicators and endocrine fertility traits in dairy cows

The relationships between dairy cow milk-based energy status (ES) indicators and fertility traits were studied during periods 8 to 21, 22 to 35, 36 to 49, and 50 to 63 d in milk. Commencement of luteal activity (C -LA) and interval from calving to the first heat (CFH), based on frequent measurements of progesterone by the management tool Herd Navigator (DeLaval), were used as fertility traits. Energy status indicator traits were milk beta-hydroxybutyrate (BHB) concentration provided by Herd Navigator and milk fat: protein ratio, concen-tration of C18:1 cis-9, the ratio of fatty acids (FA) C18:1 cis-9 and C10:0 in test-day milk samples, and predicted plasma concentration of nonesterified fatty acids (NEFA) on test days. Plasma NEFA predictions were based either directly on milk mid-infrared spectra (MIR) or on milk fatty acids based on MIR spectra (NEFAmir and NEFAfa, respectively). The average (standard deviation) C-LA was 39.3 (+/- 16.6) days, and the average CFH was 50.7 (+/- 17.2) days. The correlations between fertility traits and ES indicators tended to be higher for multiparous (r < 0.28) than for primiparous (r < 0.16) cows. All correlations were lower in the last period than in the other periods. In period 1, correlations of C-LA with NEFAfa and BHB, respectively, were 0.15 and 0.14 for primiparous and 0.26 and 0.22 for multiparous cows. The associations between fertility traits and ES indicators indicated that negative ES during the first weeks postpartum may delay the onset of luteal activity. Milk FPR was not as good an indicator for cow ES as other indicators. According to these findings, predictions of plasma NEFA and milk FA based on milk MIR spectra of routine test-day samples and the frequent measurement of milk BHB by Herd Navigator gave equally good predictions of cow ES during the first weeks of lactation. Our results indicate that routinely measured milk traits can be used for ES evaluation in early lactation.Peer reviewe

Animal board invited review: Genomic-based improvement of cattle in response to climate change

Climate change brings challenges to cattle production, such as the need to adapt to new climates and pressure to reduce greenhouse emissions (GHG). In general, the improvement of traits in current breeding goals is favourably correlated with the reduction of GHG. Current breeding goals and tools for increasing cattle production efficiency have reduced GHG. The same amount of production can be achieved by a much smaller number of animals. Genomic selection (GS) may offer a cost-effective way of using an efficient breeding approach, even in low- and middle-income countries. As climate change increases the intensity of heatwaves, adaptation to heat stress leads to lower efficiency of production and, thus, is unfavourable to the goal of reducing GHG. Furthermore, there is evidence that heat stress during cow pregnancy can have many generation-long lowering effects on milk production. Both adaptation and reduction of GHG are among the difficult-to-measure traits for which GS is more efficient and suitable than the traditional non-genomic breeding evaluation approach. Nevertheless, the commonly used within-breed selection may be insufficient to meet the new challenges; thus, cross-breeding based on selecting highly efficient and highly adaptive breeds may be needed. Genomic introgression offers an efficient approach for cross-breeding that is expected to provide high genetic progress with a low rate of inbreeding. However, well-adapted breeds may have a small number of animals, which is a source of concern from a genetic biodiversity point of view. Furthermore, low animal numbers also limit the efficiency of genomic introgression. Sustainable cattle production in countries that have already intensified production is likely to emphasise better health, reproduction, feed efficiency, heat stress and other adaptation traits instead of higher production. This may require the application of innovative technologies for phenotyping and further use of new big data techniques to extract information for breeding

Genetic analyses of metabolic body weight, carcass weight and body conformation traits in Nordic dairy cattle

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Developing an indicator for body fat mobilisation using mid-infrared spectrometry of milk samples in dairy cows

peer reviewedHigh energy requirement in the initiation of lactation may force dairy cows to mobilize energy from body tissue which leads to negative energy balance (EB). Negative EB can predispose cows to various health and fertility problems, and therefore should be considered in dairy cattle breeding programs especially if feed efficiency traits are included in breeding objectives. However, measuring of EB is difficult and estimates are imprecise. When a cow is in negative EB and mobilizing its fat reserves, concentrations of milk fatty acids and blood non-esterified fatty acids (NEFA) change. Therefore, it is possible to use these changes as biomarkers for energy status. Mid-infrared spectrometry (MIR) is a routinely used tool for milk samples and many milk fatty acids can be predicted with high accuracy by MIR. Our objective was to assess the capability of MIR to predict blood plasma NEFA concentration from milk samples. Milk and corresponding blood samples were collected from Nordic Red dairy cows in three research farms between 2013 and 2016. There were altogether 1585 milk spectral readings and 809 NEFA records from 141 cows in the data set. Partial least squares regression was used to predict NEFA and EB from MIR spectral data. The coefficient of determination of cross validation (R2cv) for NEFA was 0.64 when leave-one-out cross validation was used for the whole data set. Higher R2cv values were found when predicting blood plasma NEFA concentration from evening milk samples (0.67), probably because fatty acid concentrations in milk vary slower than NEFA concentration in blood. The robustness of the developed prediction equation was inspected by calibrating the equations with records from the cows from two research herds and then predicting NEFA for cows from the other herd, so that there were differences in the environment of the calibration data (130 NEFA obs) and test data (647 NEFA obs.) sets. Nevertheless, R2 in the test data was 0.58 and RMSE 0.19 mmol/l, which indicates that the model is robust. Keywords: mid-infrared spectroscopy, non-esterified fatty acids, energy balanc

Cow-specific diet digestibility predictions based on near-infrared reflectance spectroscopy scans of faecal samples

201

Weathering and Antimicrobial Properties of Laminate and Powder Coatings Containing Silver Phosphate Glass Used as High-Touch Surfaces

Increasing the use of hygienic high-touch surfaces with antimicrobial properties in health care and public spaces is one way to hinder the spread of bacteria and infections. This study investigates the antimicrobial efficacy and surface reactivity of commercial laminate and powder coated surfaces treated with silver-doped phosphate glass as antimicrobial additive towards two model bacterial strains, Escherichia coli and Bacillus subtilis, in relation to surface weathering and repeated cleaning. High-touch conditions in indoor environments were simulated by different extents of pre-weathering (repeated daily cycles in relative humidity at constant temperature) and simplified fingerprint contact by depositing small droplets of artificial sweat. The results elucidate that the antimicrobial efficacy was highly bacteria dependent (Gram-positive or Gram-negative), not hampered by differences in surface weathering but influenced by the amount of silver-doped additive. No detectable amounts of silver were observed at the top surfaces, though silver was released into artificial sweat in concentrations a thousand times lower than regulatory threshold values stipulated for materials and polymers in food contact. Surface cleaning with an oxidizing chemical agent was more efficient in killing bacteria compared with an agent composed of biologically degradable constituents. Cleaning with the oxidizing agent resulted further in increased wettability and presence of residues on the surfaces, effects that were beneficial from an antimicrobial efficacy perspective.QC 20220707</p

Genetic correlations between energy status indicator traits and female fertility in primiparous Nordic Red Dairy cattle

202

Developing an indicator for body fat mobilisation using mid-infrared spectrometry of milk samples in dairy cows

201