Time required to determine performance variables and production efficiency of lactating dairy cows

Thirty-five lactating dairy cows throughout weeks of lactation (WOL) 16 to 30 were used to determine optimal time needed for reliable measurement of performance variables, and to classify the cows into high-, medium-, and low-efficiency groups. Individual performance variables [body weight (BW), dry matter intake (DMI), and milk production] were measured daily with a computerized monitoring system. Body condition was visually scored weekly and used to calculate retained or depleted body energy as a result of fat content change (RE_F). Milk composition was analyzed weekly. Body weight, DMI, and total recovered energy (RE), which represents energy in milk production plus RE_F, were summarized weekly. Efficiency was calculated as RE/DMI and as residual feed intake (RFI; i.e., the difference between actual and expected DMI), which was calculated from multiple linear regression of DMI dependence on BW^0.75 and RE. Unexpectedly, it was found that BW did not affect DMI and RE/DMI. Changes and relative changes in phenotypic coefficient of variation and correlations among data from shortened tests ranging from 1 wk (WOL 16) to a sequence of 15-wk tests were used to determine optimal test period durations for 5 traits: BW, DMI, RE, RE/DMI, and RFI. Traits were fitted into a mixed model with repeated measures. For each week, the traits were summarized as a sequence of cumulative data, starting from WOL 16 and cumulated over periods that increased in 1-wk steps up to WOL 16 to 29. Weekly cumulations were compared with those for entire test period (WOL 16 to 30). Consistency of each cow’s efficiency classification as high, medium, or low was tested by the total-agreement procedure; the kappa index P-value was used. Throughout WOL 16 to 30, the effects of increasing test period duration on between-animal coefficient of variation differed with respect to the various performance variables and RE/DMI: it tended to change with respect to BW, did not change with respect to DMI, and decreased with respect to RE and RE/DMI. In conclusion, compared with a 15-wk study, a 2-wk study can classify RFI and RE/DMI to 3 efficiency levels, with an individual correlation coefficient of 0.6. When the study was carried out over 3 wk or more, the lowest significant index of the classification was P < 0.004, the lowest individual correlation coefficient was 0.65, and its lowest significance was P < 0.01. The current study indicated that the insignificant effect of the BW of dairy lactating cows on their DMI should be validated in more studies.     

Lactation performance and feeding behavior of dairy cows supplemented via automatic feeders with soy hulls or barley based pellets

The potential of soy hulls to replace barley grain in pellets supplemented to lactating cows was measured in automatic concentrate feeders (ACF). Thirty-six cows were divided into 2 equal groups and fed 1 of the 2 experimental pellet supplements individually for 7 wk. All cows were group-fed a basic mixture along the feeding lane (~64% of dietary DM) plus a pelleted additive containing 50% barley or soy hulls as barley replacer, fed individually to each cow via the ACF in 6 feeding windows. Extent and rate of in vitro DM digestibility were similar for both types of pellets; however, NDF content and digestibility were higher in the soy hulls pellets. Average number of rewarded cow visits at the ACF, pellets intake per meal, and accumulated intake of pellets (8.64 kg/d DM) were similar in the 2 experimental groups. Most pellets were consumed during day and night in the first 2 h after feeding windows were opened. Total visits per day in the ACF and the maximal interval between visits were similar for the 2 pellets, indicating similar attractiveness to the cow. Predicted intake of the basic mixture was similar in both groups (14.8 to 15.1 kg of DM/d). Higher milk fat content was observed in the soy hulls-fed cows, whereas higher milk protein content was found in the barley-fed cows. Milk yield was similar in both groups. Data suggest that replacement of barley pellets with soy hulls pellets may slightly enhance milk fat while reducing milk protein production for dairy herds using automatic milking systems.     

Performance and welfare of high-yielding dairy cows subjected to 5 or 8 cooling sessions daily under hot and humid climate

The objectives were to determine the effects of cooling of high-yielding dairy cows under a hot and humid climate on intake, milk yield, rumination time, and welfare parameters. Forty-two multiparous Israeli Holstein dairy cows were divided into 2 treatment groups and were housed in an open barn divided into 2 pens. The groups were subjected to different cooling schedules, in a crossover design as follows: cows were exposed to 5 or 8 cooling sessions per day (designated 5CS and 8CS, respectively) in the holding area of the milking parlor. Each period lasted 4 wk, and then treatments were switched for another 4-wk period. Each cooling session lasted 45 min, comprising cycles of 30s of showering and 4.5 min of ventilation without showering. Respiration rate and rectal temperature were recorded twice per week (Monday and Thursday) at 0630 and 1600 h. Rumination and lying times were recorded automatically. Rectal temperatures were 0.16 and 1.08°C lower in 8CS than in 5CS cows in the morning and afternoon, respectively. Respiration rate was lower in 8CS than in 5CS cows in the morning (49.1 and 54.6 breaths/min, respectively), and more so in the afternoon (50.0 and 83.0 breaths/min, respectively). Dry matter intake and milk yields were 9.3 and 9.6% higher in the 8CS than in the 5CS cows (27.0 vs. 24.7 and 40.1 vs. 36.6 kg/d, respectively), with no differences in milk fat and protein contents. Daily rumination time was 7.4% longer in the 8CS than in the 5CS (440.1 and 409.6 min/d, respectively); however, rumination time per unit of dry matter or neutral detergent fiber consumed was higher in the 5CS than in the 8CS cows. Although the 8CS cows moved 3 times more to the milking area for extra cooling sessions than the 5CS ones, they spent 9.9 min/d more than the 5CS ones in lying down (484.4 and 474.5 min/d, respectively), and used more of their free time (excluding milking and feeding time) in resting than the 5CS cows: 52.0 and 43.9%, respectively. It appears that increasing the cooling frequency from 5 to 8 times per day improved their feeling of welfare, so they could spend more time lying and ruminating. In conclusion, increasing the cooling frequency of high-yielding dairy cows under hot and humid conditions from 5 to 8 times a day increased their intake and milk yield, and lowered their respiration rate and rectal temperature. Moreover, the 8CS cows spent more time resting than 5CS cows, an indication that increasing cooling frequency improved animal welfare.     

Effect of soy addition on microwavable pocket-type flat doughs

Microwavable frozen baked goods are widely used by the food industry. However, the altered heat and mass transfer patterns associated with microwave radiation result in tough and rubbery baked products due to reduced plasticization of the polymers. Ingredients with high water-holding capacity and high content of polar lipids have been shown to enhance gluten plasticization and to improve water retention. Therefore, this study explored the physicochemical changes imparted by microwave baking of pocket-type flat doughs with and without soy added at 10%, 20%, and 26% and compared these to their conventionally baked counterparts. Microwave baking resulted in a soft, rubbery, and tough wheat product with increased "freezable" water. Soy was added to the formulation as a means to improve polymer plasticization. Conventional baking of soy doughs resulted in rubbery and tough products due to changes in water state and mobility (freezable water approximately 15 compared with 7.09 of the control). However, soy reduced the cohesiveness of the microwave baked products reaching the lowest value at 20% soy addition (cohesiveness 0.33 ± 1, comparable to that of the conventionally baked control). These data suggest that reduction of water mobility induced by soy proteins and polar lipids (confirmed by thermogravimetric analysis [TGA] and 1H nuclear magnetic resonance [1H NMR]) possibly plasticized the starch-gluten network of microwave baked soy doughs. Thus, soy was shown to improve the texture of microwave baked pocket-type flat doughs although further formula optimization is warranted. PRACTICAL APPLICATION: Microwavable pocket-type flat doughs are used frequently by the food industry to enrobe meat, vegetable, and sweet items for convenient meal delivery. Microwave heating of such doughs induces the development of crustless products compared to conventionally baked products, resulting in a tough and rubbery texture. Partial substitution of wheat flour with soy, in the form of soy flour and soy milk powder, prevented the deleterious textural changes associated with microwave heating. These results suggest that soy is a functional ingredient for the textural improvement of microwavable pocket-type flat doughs.     

A preliminary investigation into a genetic basis for cis-3-hexen-1-ol odour perception: A genome-wide association approach

Odour perception is controlled by environmental and genetic influences. Most people can discriminate over 10,000 different odours, but the molecular basis of this ability is poorly understood. Little is known about which odorant receptors (ORs) detect what odour compounds, and additional research is required to gain knowledge of why detection thresholds for some odorants vary 1000-fold, or more, across people. The primary purpose of this paper is to describe a research strategy for investigating the genetic basis of human odour perception. Background information on human olfaction, human genetics and the associated research approaches is presented. This is followed by a case study on cis-3-hexen-1-ol, a compound which contributes to the ‘green leaf’ odour (and flavour) in fruit, vegetables and wine. Odour detection threshold data for 48 participants were obtained using the rating R-index methodology. The ability to perceive cis-3-hexen-1-ol odour was tested for association with genetic variability on a genome-wide scale by microarray probe genotyping. A group of significant SNPs on chromosome 6 around the SNP rs9295791 was identified and these localise with a cluster of OR genes which could potentially be involved in perception of cis-3-hexen-1-ol. Further steps required to identify genes and alleles that encode the different ability to perceive cis-3-hexen-1-ol are outlined.     

Cell-free protein synthesis and assembly on a biochip

Biologically active complexes such as ribosomes and bacteriophages are formed through the self-assembly of proteins and nucleic acids. Recapitulating these biological self-assembly processes in a cell-free environment offers a way to develop synthetic biodevices. To visualize and understand the assembly process, a platform is required that enables simultaneous synthesis, assembly and imaging at the nanoscale. Here, we show that a silicon dioxide grid, used to support samples in transmission electron microscopy, can be modified into a biochip to combine in situ protein synthesis, assembly and imaging. Light is used to pattern the biochip surface with genes that encode specific proteins, and antibody traps that bind and assemble the nascent proteins. Using transmission electron microscopy imaging we show that protein nanotubes synthesized on the biochip surface in the presence of antibody traps efficiently assembled on these traps, but pre-assembled nanotubes were not effectively captured. Moreover, synthesis of green fluorescent protein from its immobilized gene generated a gradient of captured proteins decreasing in concentration away from the gene source. This biochip could be used to create spatial patterns of proteins assembled on surfaces.     

In vitro characterization of PBLG-g-HA/ PLLA nanocomposite scaffolds

The purpose of the present study was to synthesize a new composites scaffold containing poly(γ-benzyl-L-glutamate) modified hydroxyapatite/(poly(L-lactic acid))(PBLG-g-HA/PLLA) and to investigate their in vitro behaviour on bone mesenchymal stromal cells(BMSCs). The results demonstrated that BMSC proliferation was signifi cantly increased on PBLG-g-HA/PLLA scaffolds after 3 and 7 days post seeding when compared to PLLA and HA/PLLA scaffolds. The in vitro osteogenic differentiation also favoured the composite PBLG-g-HA/PLLA scaffolds when compared to controls by signifi cantly increasing Runx2, ALP or osteocalcin mRNA expression as assessed by real-time PCR. The results illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications. And the in vivo testing further confi rms the PBLG-gHA/PLLA scaffolds' potentioal for healing critical bone defects.     

Fluorescent thermostable crosslinked poly(dodecylmethacrylate) composites based on porous polyethylene and CdSe/ZnS quantum dots

Hybrid fluorescent polymer–inorganic nanoparticle composites have a broad set of valuable properties that allow them to be considered promising materials for photonics and photovoltaics. The design and methods of preparation of these composites are among the most critical topics of modern materials science. In this work, we have developed an approach to the preparation of composite polymer films with bright fluorescence and high thermostability. These composite films are based on a porous polyethylene (PE) matrix, the pores of which are filled by crosslinked poly(dodecylmethacrylate) and CdSe/ZnS core/shell quantum dots (QDs). The composites obtained are transparent in the visible spectral region and are able to withstand heating to high temperature and a considerable mechanical stress without loss of this property. These QD–PE composite films contain QDs in a high concentration and display very bright fluorescence, while they retain the mechanical properties of the initial porous PE film. Thus, the developed approach makes it possible to obtain composite materials combining the advantageous properties of PE and QDs without appreciable loss of individual component characteristics. A novel approach to the preparation of fluorescence composite polymer films, which have transparency, dimensional thermostability and resistance to mechanical stress, has been developed. © 2018 Society of Chemical Industry