Feeding Of Cows Research Articles

Macromineral, micromineral and metal concentration of bovine colostrum samples from Salzburg, Austria

BackgroundBesides immunoglobulins which are essential for the calf to prevent Failure of Transfer of Passive Immunity (FTPI) colostrum contains multiple other constituents such microminerals, macrominerals and metals. The concentration of the minerals seems to be higher in colostrum than in normal milk. The aims of this study were to describe macromineral, micromineral and metal concentration of bovine colostrum samples from Salzburg, Austria and to see if there are differences in the concentrations between different cow feeding strategies and farm locations. MethodsTherefore, 1050 individual colostrum samples were collected from 72 dairy farms from different districts of Salzburg. All colostrum samples were analysed for macromineral (K, Mg, Na), micromineral (Co, Cu, Fe, I, Mg, Se, Zn) andmetal (As, Ba, Cd, Li, Mo, Ni, Pb, Sr, Tl, U) concentrations by inductive coupled plasma mass spectrometry. ResultsThe mean K, Mg and Na levels were 1218.71 mg l-1, 245.44 mg l-1 and 358.62 mg l-1, respectively. The micromineral concentrations of I, Se, Co and Zn were significantly higher in colostrum from dairy cows feeding a Total-Mixed-Ration during the lactation period in comparison to cows receiving microminerals by hand feeding, transponder feeding or via a licking bucket or licking stone. The metal analysis showed that in three farms, most of the colostrum samples showed Pb levels above the limit of 5 µg l-1. ImplicationsHerd-level factors need to be addressed to elevate micromineral concentrations and to reduce metal concentrations in colostrum from dairy cows from Salzburg, Austria. ConclusionThe results show that the macrominerals K, Mg and Na are within the range of published concentrations. For the microminerals, Co, Cu, Fe, I, Mg, Se and Zn the concentrations were significantly different depending on the mineral feeding strategies during the lactation and dry period. Metal concentrations of As, Ba, Cd, Li, Mo, Ni, Pb, Sr, Tl and U differed between the districts of Salzburg.

Assessing the Risk of Spreading Clostridioides difficile and Its Toxins Within the Dairy Farm

Clostridioides difficile currently constitutes a major pathogen of the gastrointestinal tract, which poses a significant growing burden on medicine and veterinary medicine in many regions. A farm was assessed (feed table, silage pit, and feces (healthy animals, emaciated animals, and animals with mastitis)) for the presence of C. difficile toxins using the PCR method and for the microbiome in cow feed and feces using NGS technology, one month apart. C. difficile toxin A and binary toxin were detected in feed samples. C. difficile toxin genes were found in the feces of sick animals two to three times more often than in healthy animals. Analysis of the microbial community of cow feces revealed that, during the month, the animals experienced major changes in the community structure associated with the accumulation of pathogenic bacteria, in particular Paeniclostridium sp., as well as with the development of methanogenic archaea of the Methanobacteriaceae and associated microorganisms (Lachnospiraceae and Anaerovoracaceae), which may speak of a decrease in feed efficiency and, subsequently, animal productivity. Thus, it seems likely that C. difficile enters the gastrointestinal tract of animals through feed, while animals weakened by diseases are more sensitive to the reproduction of pathogens in the GIT due to a weakened organism.

Economics of Dairy Cow Feeding in Ngoma District, Rwanda

Economics of Dairy Cow Feeding in Ngoma District, Rwanda

Revealing host genome–microbiome networks underlying feed efficiency in dairy cows

Ruminants have the ability to digest human-inedible plant materials, due to the symbiotic relationship with the rumen microbiota. Rumen microbes supply short chain fatty acids, amino acids, and vitamins to dairy cows that are used for maintenance, growth, and lactation functions. The main goal of this study was to investigate gene-microbiome networks underlying feed efficiency traits by integrating genotypic, microbial, and phenotypic data from lactating dairy cows. Data consisted of dry matter intake (DMI), net energy secreted in milk, and residual feed intake (RFI) records, SNP genotype, and 16S rRNA rumen microbial abundances from 448 mid-lactation Holstein cows. We first assessed marginal associations between genotypes and phenotypic and microbial traits through genomic scans, and then, in regions with multiple significant hits, we assessed gene-microbiome-phenotype networks using causal structural learning algorithms. We found significant regions co-localizing the rumen microbiome and feed efficiency traits. Interestingly, we found three types of network relationships: (1) the cow genome directly affects both rumen microbial abundances and feed efficiency traits; (2) the cow genome (Chr3: 116.5 Mb) indirectly affects RFI, mediated by the abundance of Syntrophococcus, Prevotella, and an unknown genus of Class Bacilli; and (3) the cow genome (Chr7: 52.8 Mb and Chr11: 6.1–6.2 Mb) affects the abundance of Rikenellaceae RC9 gut group mediated by DMI. Our findings shed light on how the host genome acts directly and indirectly on the rumen microbiome and feed efficiency traits and the potential benefits of the inclusion of specific microbes in selection indexes or as correlated traits in breeding programs. Overall, the multistep approach described here, combining whole-genome scans and causal network reconstruction, allows us to reveal the relationship between genome and microbiome underlying dairy cow feed efficiency.

Protected fats in feeding of highly productive cows

Highly productive animals experience energy deficiency at the beginning of lactation up to 30 % of their energy needs, since cows spend more energy on milk production than they intake with feed. Therefore, to maintain a high level of productivity and minimize live weight loss of cows, it is necessary to increase the energy supply of rations. For these purposes, along with the use of high-quality feed and a decrease in the proportion of starchy grain concentrates in the ration structure, various types of fats are used in feeding of cows, since their energy value is more than 2 times higher than proteins and carbohydrates. The purpose of the research was to study the eff ectiveness of using protected vegetable fats in feeding of highly productive lactating cows. Comprehensive studies were carried out to investigate the effectiveness of using new protected vegetable fats: hydrogenated (Ultra Feed F) and fractionated (Extra Feed F) in feeding of highly productive lactating cows and an assessment of the effectiveness of their use was given. It was recommended as a result of the research that in order to ensure milk productivity of cows at a level of more than 7000 kg of milk (7000–9000 kg), livestock farms should ensure the concentration of metabolic energy in the dry matter of the ration of at least 10.7 MJ/kg, with possible compensation for the deficit in the level of metabolic energy up to 11.0 MJ/kg with protected vegetable fats of domestic production (fractionated Extra Feed F and hydrogenated Ultra Feed F) in the amount of 300 g/head/day during the period of 21–120 days of lactation.

Qualitative indicators of milk and fermented milk products when activated zeolite and probiotics are included in the diet of cows

Relevance. The quality of milk depends on the season of the year, the breed of animals, the state of metabolism, and the characteristics of feeding and maintenance technology. The quality of milk determines its technological properties and the quality of its processed products.Methods. The content of somatic cells in milk, the acidity of milk, cottage cheese, yogurt, and syneresis of yogurt were determined. In milk processing products, the content of the mass fraction of nitrogen and crude protein, crude ash, calcium, and phosphorus was determined.Results. When feeding cows with the yeast probiotic activated zeolite and the phytoprobiotic “Provitol”, a significant decrease in the content of somatic cells in freshly milked milk of cows was established by 13.02% (p < 0.05). Significantly lower milk acidity values were established (by 6.00% (p < 0.001) and 12.79% (p < 0.001), respectively), significantly higher yogurt acidity values (by 6.00% (p < 0.001) and 12.79% (p < 0.001), respectively, significantly lower yogurt syneresis (by 4.70% (p < 0.001) and 3.10% (p < 0.01), respectively). The use of activated zeolite and yeast probiotic “Kluver Pro” in the diets leads to a significantly higher content (compared with the control) of the mass fraction of fat in cottage cheese and yogurt — by 10.47 abs. % (p < 0.001) and 4.58 abs. % (p < 0.001).

Impact of pasture feeding cows and seasonality on the concentration of selected fat-soluble compounds in milk and their ability to be used as biomarkers of “Grass-Fed” dairy

This study investigated the impact of proportion of pasture in the cow diet on the concentration of selected fat-soluble compounds in milk including β-carotene, lutein, retinol (vitamin A), α-tocopherol (vitamin E) and zeaxanthin. Bulk tank milk samples (n = 102) were collected weekly (n = 34) across an entire lactation from three herds operating either a high (GRS), medium (PMR) or no pasture allowance (TMR) feeding system. Concentrations of β-carotene and lutein increased significantly with increasing pasture allowance, with a > 2 fold increase of β-carotene in milk, between high and no pasture allowance treatments. GRS feeding system resulted in milks with higher concentrations of retinol, α-tocopherol, and zeaxanthin, compared to both PMR and TMR systems. A biomarker model based on the fat-soluble compounds concentration in milk, demonstrated excellent differentiation of high pasture allowance derived milks from that of medium and no pasture milks, with area under the curve scores of 0.955 and 0.971 respectively. Strong correlations were observed between the concentrations of lutein and zeaxanthin in milk and the milks corresponding yellow colour, while a significant correlation was exhibited between β-carotene and b*-value. Such correlations with milk colour may have a significant impact on the consumer preference of milk and dairy products produced therefrom.

Feeding Cows with Olive Cake Enriched in Polyphenols Improves the Sustainability and Enhances the Nutritional and Organoleptic Features of Fresh Caciocavallo Cheese.

In this study, Caciocavallo, a typical cheese produced in Sicily Island (Italy), was obtained from the milk of dairy cows fed with and without enriched olive cake (ECO and CTR, respectively) in order to evaluate nutritional, microbiological, volatile, and sensory differences in cheeses. ECO cheese showed greater (p < 0.05) MUFA and PUFA and polyphenols content and lower SFA content than CTR cheese. Microbiological analyses revealed the absence of Salmonella, Listeria monocytogenes, Escherichia coli, and E. coli O157, and no significant differences in the viable counts of the remaining microbial groups analyzed, between samples. Thermophilic lactococci were more prevalent in ECO cheese. The implementation of a culture-independent method, such as PCR-DGGE analyses, revealed the presence of a more diverse microbial population in both cheeses. Regarding the volatile compounds profile, long-chain free fatty acids were more abundant in the ECO cheese, resulting in a healthier free fatty acid profile. This study also showed that, especially for their appearance and taste, consumers mostly appreciated the ECO cheese. The results show that using enriched olive cake could enhance the sustainability and the quality of Ragusano cheese, improving not only the health of its consumers but also positively influencing tastes and acceptability.

Implementasi Smart Cow Farming Technology untuk Monitoring Pertumbuhan Sapi dan Peningkatan Skala Usaha pada Kelompok Peternak Sapi DiBa Farm Kabupaten Lampung Selatan

The DiBa Farm Livestock Group faces several urgent issues that need to be addressed not all cows can achieve the minimum weight gain target of 1.5 kg per day. Monitoring of cow growth productivity is done manually; (3) the calculation of the cost of goods sold is also still done manually. The partner's marketing of livestock products is limited to regular customers within the South Lampung area only. Based on these prioritized issues, the proposed solutions and methods are implementing a wheelbarrow tool with a digital scale for transporting cow feed using IoT technology. Implementing a cow growth monitoring application using RFID. Implementing a website-based application to automatically determine the Cost of Goods Sold for cows. Implementing a digital marketing application for cow sales that can be accessed via a website. Providing training and assistance related to digital marketing strategies. Based on the evaluation results, it was found that the implementation of Smart Cow Farming Technology 100% improved the partners' knowledge of its usage. The average cow growth increased monthly, from 45 kg to 50 kg. Additionally, there was a 25% increase in profits due to the implementation of the cost of goods sold calculation application and the online cow sales application. The evaluation results from the digital marketing training activities also showed that 85% of the partners' knowledge and understanding improved in terms of using digital marketing.

Effects of cow feed efficiency, longevity, heterosis, and lifetime productivity on profitability of heifer selection and cow-calf operations

This study investigated factors influencing heifer replacement and cow-calf profitability using 361 cows (born 2011-2018) at the Lacombe Research and Development Centre, Alberta, Canada. Profitability was measured by marginal returns (MR) incorporating feed costs, heifer opportunity cost, calf and cull revenues, and a premium for cows retained in the herd. The study evaluated the linear effects of lifetime productivity, feed efficiency (residual feed intake adjusted for off-test backfat thickness; RFIfat), and genomic retained heterozygosity, an indicator of heterosis, on MR, feed costs, total costs, and net revenue (NR). Lifetime productivity, defined by the cumulative weight of calves weaned, was positively associated with MR and NR (P &lt; 0.01). RFIfat influenced total cost, MR, and NR (P &lt; 0.05), with MR improved by $168.50 cow-1 yr-1 for each unit decrease in RFIfat, although regression and group mean comparisons were not fully consistent. Genomic retained heterozygosity positively impacted MR and NR, with a 10% increase enhanced MR and NR by $21.80 and $20.50 cow-1 yr-1, respectively. Cow breed type did not affect longevity, MR, or NR. In conclusion, RFIfat and genomic diversity were important factors to consider in heifer replacement decisions when lifetime DMI was estimated as described in the present study.

Circular Economy, Dairy Cow Feed Leftovers, and Withania somnifera Supplementation: Effects on Black Belly Ram's Libido, Sperm Quality, Sexual Behavior, and Hemogram Values.

Considering a circular economy perspective, this study evaluates the possible effect of targeted short-term supplementation with Withania somnifera L. (WS; Ashwagandha) on ram's seminal quality, socio-sexual behaviors, and blood constituents. Black Belly rams (n = 20) received a basal diet comprising feed-leftovers from dairy cows in the north-arid Mexico (i.e., Comarca Lagunera CL). The experimental units, with proven libido and fertility, were homogeneous in terms of age (3.41 ± 0.21 yr.), live weight (LW; 53.8 ± 3.3 kg), body condition (BC; 2.96 ± 0.01 units), initial sperm concentration (2387 ± 804 × 106), and viability (23.9 ± 15.6%). Rams were randomly assigned during the transition reproductive period (i.e., May to Jun; 25° NL) to three treatment groups: non-supplemented control group (CONT; n = 6), low WS-supplemented (LWS; i.e., 100 mg kg LW-1 d-1 × 40 d; n = 7), and high-WS-supplemented (HWS; i.e., 200 mg kg LW-1 d-1 × 40 d; n = 7). The basal leftover diet was offered twice daily (0700 and 1600 h); the experimental period (EP) lasted 47 d. No differences (p > 0.05) among treatments occurred regarding LW and BCS at the onset of the EP. Whereas the greater scrotal circumference (SCRC, cm) arose in the LWS and CONT rams, an increased ejaculated volume (VOLEJA, mL) occurred in the WS-rams. A total of 5/9 (i.e., 55%) appetitive and 3/3 (i.e., 100%) consummatory sexual behaviors favored (p < 0.05) the WS-rams, particularly the HWS rams, towards the final EP. The same was true (p < 0.05) regarding the hemogram variables white blood cell count (×109 cells L-1), hemoglobin concentration (g dL-1), and medium corpuscular volume (fL). This study, based on a rethink-reuse-reduce enquiry approach, enabled connectedness between two noteworthy animal systems in the CL: dairy cows and meat sheep schemes. Certainly, the use of dairy cow feed-leftovers aligned with the short-term supplementation with WS promoted enhanced testicular function, augmented seminal volume, and an increased sexual behavior in Black Belly rams in northern Mexico. Finally, while our research outcomes should enhance not only the resilience and sustainability of sheep production and the well-being of sheep-producers and their families, it may also embrace clinical translational applications.

Physical and Chemical Quality of Sorghum and Indigofera Silage as Cow Feed at the Integrated Agriculture Center of PT Arutmin Indonesia Asam Tambang

Physical and Chemical Quality of Sorghum and Indigofera Silage as Cow Feed at the Integrated Agriculture Center of PT Arutmin Indonesia Asam Tambang

Detection of kernels in maize forage using hyperspectral imaging

In this study, the use of hyperspectral imaging was examined to enhance the kernel processing assessment of maize forage, which is crucial for optimizing the production of dairy cow feed and biogas production. As the visual contrast between the kernels and other crop particles is quite limited, spectral imaging could provide better kernel classification. A pushbroom hyperspectral imaging system was used, scanning samples collected during maize harvesting in the 400–1000 nm range. A PLSDA model for pixel classification was developed to distinguish kernel spectra from the other particles in the forage, achieving a pixel-level classification accuracy of 95.2 %. Next, the most important wavelengths were identified by means of a stepwise procedure using the Wilks Lambda criterion. A Pixel classification using the top five discriminating wavelengths achieved nearly the same accuracy as the full spectrum wavelength model (95.2 % compared to 93.5 %) and did considerably better than the RGB classifier’s 86.3 % accuracy. Finally, these top 5 discriminating wavebands were applied in an object detection deep learning model, more specifically a Faster R-CNN model. While object detection based on these 5 wavebands stilled outperformed object detection based on RGB wavebands, detection performance, as measured by AP50, was rather low. This weak performance resulted from the low resolution of the hyperspectral imaging camera.

Fermented total mixed ration enhances nutrient digestibility and modulates the milk components and fecal microbial community in lactating Holstein dairy cows.

Fermented total mixed ration (FTMR) is an effective method of preserving high-moisture byproducts with higher aerobic stability after fermentation. FTMR has the potential to fulfill the daily nutritional requirements of cattle and enhance their production performance. The objective of this research was to examine the influence of FTMR on lactation performance, total tract apparent digestibility, fecal microbiota communities, and fermentation profiles in lactating dairy cows. A total of 12 cows were randomly assigned into two groups: the TMR group and the FTMR group. The TMR group was fed a total mixed ration (TMR) diet, and the FTMR group was fed an FTMR diet. The FTMR did not impact milk yield in dairy cows despite a decrease in dry matter intake, which increased the efficiency of the feed. In contrast to that in the TMR group, the milk fat content in the FTMR group was greater. The FTMR group showed greater digestibility of neutral detergent fiber (NDF), organic matter (OM), dry matter (DM), crude protein (CP), and acid detergent fiber (ADF) in the total digestive tract than did the TMR group. The FTMR increased the concentration of butyrate in the fecal matter and reduced the pH of the feces. The Chao1, ACE, and Shannon indices of the archaeal community in dairy cow feces were significantly higher in cow fed the FTMR compared to those fed the TMR. LefSe analysis revealed higher levels of Oscillospira, Lactobacillus, Prevotella, and Dehalobacterium in the feces of dairy cows fed the FTMR than in those fed the TMR. However, the abundances of Roseburia, rc4-4, Bulleidia and Sharpea exhibited the opposite trend. The abundances of Halobacteria, Halobacteriales, and Halobacteriaceae, which are biomarkers for distinguishing fecal archaea in the TMR from the FTMR, were substantially greater in the feces of dairy cows that consumed the TMR than in those that consumed the FTMR. Therefore, FTMR can improve the milk fat content, total tract apparent feed digestibility efficiency, and diversity of archaea in the feces. Additionally, this work provides a theoretical basis for the feasibility of FTMR feeding for dairy cows.

Organophosphate Esters in Raw Cow Milk and Cow's Drinking Water and Feed from China: Occurrence, Regional Distribution, and Dietary Exposure Assessment.

Organophosphate esters (OPEs) have been widely produced and used, while little is known about their occurrence in the food chain and potential sources. In this study, raw cow milk, cow drinking water, and feed were collected from pastures across China, and OPEs were tested to explore the occurrence and transmission of OPEs in the food chain and to further assess daily OPE intakes for cows and humans via certain food consumption. The median level of ∑OPEs (sum of 15 OPEs) in raw milk was 2140 pg/mL, and tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPE. Levels of OPEs in water were lower than those in raw milk except for triethyl phosphate (TEP), while levels of most OPEs in feed were significantly higher than those in raw milk (adjusted by dry weight). The estimated dietary intake of OPEs via feed for cows was 2530 ng/kg bw/day, which was much higher than that via water (742 ng/kg bw/day), indicating that feed was a more critical exposure source. For liquid milk consumers, the high-exposure (95th) estimated daily intakes (EDIs) of ∑15OPE were 20 and 7.11 ng/kg bw/day for 3-17 years and adults, respectively, and it is obvious that cows had much heavier OPE intake. Finally, the calculated hazard indexes (HIs) suggested that the intake of OPEs via cow milk consumption would not pose significant health risks to the Chinese population.

Specific supplemental feeding of Sahiwal cows and their effect on body condition score, body weight and onset of reproductive cycle

Specific supplemental feeding of Sahiwal cows and their effect on body condition score, body weight and onset of reproductive cycle

Multispecies pasture diet and cow breed impacts on milk composition and quality in a seasonal spring-calving dairy production system

In recent years, there has been significant emphasis on the composition of pasture-based cow feed and the potential benefits of incorporating multispecies swards to improve sustainability and biodiversity. This study compared the effects of a conventional perennial ryegrass (PRG) monoculture supported by high chemical nitrogen (N) usage with a low chemical N application multispecies sward system (MSS) on the composition and quality of milk across lactation using spring-calving Holstein-Friesian (HF) and Jersey Holstein-Friesian (JFX) cows. Bulk milk samples (n = 144) were collected from each group at morning and evening milking on a weekly basis (n = 36) throughout lactation and analyzed for gross composition and physico-chemical properties. Cow breed had a significant impact on milk profile, with milk from HF cows having significantly smaller milk fat globule (MFG) size, higher instability index values, higher yield, and lower total solids levels, compared with JFX cows. Notably, HF cows had increased milk total solids and fat levels when fed on MSS, as opposed to the PRG-fed HF cows. Feeding MSS pasture increased creaming velocity values in mid and late lactation, and resulted in similar milk gross composition to PRG. In comparison to PRG, MSS-fed groups showed significantly increased total solids yield, including higher levels of protein and fat yield. In late lactation, MSS feeding was associated with reduced MFG size. All physicochemical properties studied (MFG size, creaming velocity, instability index) showed decreasing values from early to late lactation stage. Overall, these findings demonstrate the significant effects of cow diet, breed and stage of lactation on compositional and physico-chemical characteristics of milk, with important implications for milk processing and dairy product quality.

Changes in Parameters Registered by Innovative Technologies in Cows with Subclinical Acidosis.

The hypothesis of this study was that there were changes in biomarkers registered by innovative technologies in cows with subclinical acidosis. The aim of this study was to identify changes in the in-line milk fat-to-protein ratio and cow feeding behaviors such as reticulorumen pH, reticulorumen temperature, cow activity, and water intake with subclinical acidosis. From a total of 98 cows, 59 cows were selected to meet the following criteria (2 or more lactations, with 31 days in milk (DIM)). The selected animals were separated into two groups based on general clinical examination and reticulorumen pH: the subclinical acidosis group (SCA, n = 23) and the healthy group (HC, n = 36). During the diagnosis of subclinical acidosis and following the clinical examination of the healthy group using the BROLIS HerdLine system, the daily averages of milk yield (kg/day), milk fat (%), milk protein (%), and the milk fat-to-protein ratio were recorded. Simultaneously, by using Smaxtec technology, reticulorumen parameters and cow activity, including pH, temperature (°C), rumination time (minutes/day), and water intake (hours/day), were registered. Changes in parameters measured using innovative technologies were able to identify cows with subclinical acidosis. Cows with subclinical acidosis had a lower reticulorumen pH by 18.8% (p < 0.0001), a decreased milk yield by 10.49% (p < 0.001), a lower milk fat-to-protein ratio by 11.88% (p < 0.01), and a decreased rumination time by 6.59% (p < 0.01). However, the activity of these cows was higher by 57.19% (p < 0.001) compared to healthy cows. From a practical point of view, we suggest that veterinarians and farmers track parameters such as reticulorumen pH, milk yield, milk fat-to-protein ratio, rumination time, and activity for the identification of subclinical acidosis.

Investigating relationships between the host genome, rumen microbiome, and dairy cow feed efficiency using mediation analysis with structural equation modeling

The rumen microbiome is crucial for converting feed into absorbable nutrients used for milk synthesis, and the efficiency of this process directly impacts the profitability and sustainability of the dairy industry. Recent studies have found that the rumen microbial composition explains part of the variation in feed efficiency traits, including dry matter intake, milk energy, and residual feed intake. The main goal of this study was to reveal relationships between the host genome, rumen microbiome, and dairy cow feed efficiency using structural equation models. Our specific objectives were to (i) infer the mediation effects of the rumen microbiome on feed efficiency traits, (ii) estimate the direct and total heritability of feed efficiency traits, and (iii) calculate the direct and total breeding values of feed efficiency traits. Data consisted of dry matter intake, milk energy, and residual feed intake records, SNP genotype data, and 16S rRNA rumen microbial abundances from 448 mid-lactation Holstein cows from 2 research farms. We implemented structural equation models such that the host genome directly affects the phenotype (GP → P) and the rumen microbiome (GM → P), while the microbiome affects the phenotype (M → P), partially mediating the effect of the host genome on the phenotype (G → M → P). We found that 7 to 30% of microbes within the rumen microbial community had structural coefficients different from zero. We classified these microbes into 3 groups that could have different uses in dairy farming. Microbes with heritability <0.10 but significant causal effects on feed efficiency are attractive for external interventions. On the other hand, 2 groups of microbes with heritability ≥0.10, significant causal effects, and genetic covariances and causal effects with the same or opposite sign to feed efficiency are attractive for selective breeding, improving or decreasing the trait heritability and response to selection, respectively. In general, the inclusion of the different microbes in genomic models tends to decrease the trait heritability rather than increase it, ranging from -15% to +5%, depending on the microbial group and phenotypic trait. Our findings provide more understanding to target rumen microbes that can be manipulated, either through selection or management interventions, to improve feed efficiency traits.

Carry-over rate of per- and polyfluoroalkyl substances to raw milk and human exposure risks in different regions of China

The widespread presence of per- and polyfluoroalkyl substances (PFAS) in various environmental matrices and their adverse health effects have gained worldwide attention. Therefore, numerous studies have focused on human exposure to PFAS through different pathways, such as fish and drinking water, and little attention has been paid to milk consumption. This study aimed to explore the transfer of PFAS by investigating the occurrence of PFAS in cow feed, drinking water, and raw milk from 20 regions of China and to assess the risk of human exposure to PFAS from raw milk. In total, 13, 15, and 7 PFAS were detected in cow feed, drinking water, and raw milk with total concentrations (∑PFAS) of 5.59 ± 2.91 ng/g (mean ± standard deviation), 11.91 ± 23.12 ng/L, and 0.15 ± 0.13 ng/mL, respectively. Perfluoropentanoic acid (PFPeA) was dominant with a concentration of 2.28 ± 1.75 ng/g, approximately 40.7 % of ∑PFAS in feed. Perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) were the dominant compounds found in drinking water at 4.80 ± 14.37 and 3.01 ± 6.06 ng/L, respectively. Additionally, PFOA (0.08 ± 0.09 ng/mL) was the most significant compound in raw milk, contributing 51.5 % of ∑PFAS. Moreover, the results of the carry-over rate (COR) were as follows: perfluorooctanesulfonic acid (PFOS, 29.58 %) > PFOA (15.78 %) > perfluorobutanesulfonic acid (PFBS, 9.45 %). According to the reference dose (RfD) established by the European Food Safety Authority (EFSA) in 2018, there is a potential toxicological hazard of PFOA exposure for preschool children through milk consumption. Notably, the health risk from PFOS for 1-year-old children in Central China exceeded that observed for humans in other regions and age groups. Our results showed that PFOS and PFOA were more likely to accumulate in cows and to be constantly transferred to milk, thus increasing the human health risk, especially in children.