The current study was designed to investigate the chemical composition, amino acid content, and rumen degradation characteristics (nylon bag method) of six organic feeds to illustrate their feeding values. The feeds analyzed were: corn grain (CG), soybean cake (SC), wheat bran (WB), corn silage (CS), oat hay (OT), and alfalfa hay (AF). Our results showed that the contents of crude protein (CP) (47.46%) and ether extract (EE) (8.23%) in SC were highest. The contents of neutral detergent fiber (NDF) (65.00%) and acid detergent fiber (ADF) (39.16%) in OT were highest. The contents of total amino acid (TAA) (42.95%) and essential amino acid (EAA) (19.73%) in SC were highest. Among SC, WB, and CG, the effective degradation rate (ED) of dry matter (DM) is SC (87.89%) > WB (73.32%) > CG (64.25%); the ED value of CP is CG (82.37%) > WB (82.40%) > SC (60.47%). Among CS, OT, and AF, the effective degradation rate (ED) of DM is CS (72.68%) > OT (59.97%) > AF (58.89%); the ED value of CP is AF (76.46%) > CS (72.03%) > OT (71.99%). In conclusion, the chemical composition, amino acid content, and rumen degradation rate of SC and AF were better than those of the other four feeds.

This study investigated the effect of moderate risk level (8 µg/kg) AFB₁ in diet supplemented with or without adsorbents on lactation performance, serum parameters, milk AFM₁ content of healthy lactating cows and the AFM₁ residue exposure risk in different human age groups. Forty late healthy lactating Holstein cows (270 ± 22 d in milk; daily milk yield 21 ± 3.1 kg/d) were randomly assigned to four treatments: control diet without AFB₁ and adsorbents (CON), CON with 8 μg/kg AFB₁ (dry matter basis, AF), AF + 15 g/d adsorbent 1 (AD1), AF + 15 g/d adsorbent 2 (AD2). The experiment lasted for 19 days, including an AFB₁-challenge phase (day 1 to 14) and an AFB₁-withdraw phase (day 15 to 19). Results showed that both AFB₁ and adsorbents treatments had no significant effects on the DMI, milk yield, 3.5% FCM yield, milk components and serum parameters. Compared with the AF, AD1 and AD2 had significantly lower milk AFM₁ concentrations (93 ng/L vs. 46 ng/L vs. 51 ng/L) and transfer rates of dietary AFB₁ into milk AFM₁ (1.16% vs. 0.57% vs. 0.63%) (p < 0.05). Children aged 2–4 years old had the highest exposure risk to AFM₁ in milk in AF, with an EDI of 1.02 ng/kg bw/day and a HI of 5.11 (HI > 1 indicates a potential risk for liver cancer). Both AD1 and AD2 had obviously reductions in EDI and HI for all population groups, whereas, the EDI (≥0.25 ng/kg bw/day) and HI (≥1.23) of children aged 2–11 years old were still higher than the suggested tolerable daily intake (TDI) of 0.20 ng/kg bw/day and 1.00 (HI). In conclusion, moderate risk level AFB₁ in the diet of healthy lactating cows could cause a public health hazard and adding adsorbents in the dairy diet is an effective measure to remit AFM₁ residue in milk and its exposure risk for humans.

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Active peptides in mare milk have unique biological activities, but how the bioactive protein in mare’s milk changes under the influence of temperature has not been fully studied. Therefore, in this study, the differential expression of bioactive peptides potentially present in horse milk under different heat treatment conditions was investigated for the first time using peptidomic and bioinformatic techniques. We collected a total of 15 samples. In this study, we divided the samples into five groups, specifically, 65 °C, 30 min; 72 °C, 15 min; 83 °C; 10 min; 95 °C, 5 min; and an untreated group as a control, which involved four different temperature treatments, in order to understand changes in bioactive peptides and to identify the sequence of bioactive peptides. In the experiment, a total of 2341 active peptides were identified. The amino acid composition of the potential active peptides remained stable across different temperatures, but their abundance varied with temperature. In all, 23 peptides from 20 different proteins were identified, with the highest number of active peptides identified at 72 °C. Through database searches, we found that a majority of these peptides were within β-lactoglobulin and immunoglobulin domain proteins, which are known for their potential biological activities. These findings provide a theoretical foundation for the development of peptides with different bioactivities as potential functional foods.

Traditional methods for determining the chemical composition of cattle feces are uneconomical. In contrast, near-infrared reflectance spectroscopy (NIRS) has emerged as a successful technique for assessing chemical compositions. Therefore, in this study, the feasibility of NIRS in terms of predicting fecal chemical composition was explored. Cattle fecal samples were subjected to chemical analysis using conventional wet chemistry techniques and a NIRS spectrometer. The resulting fecal spectra were used to construct predictive equations to estimate the chemical composition of the feces in both cows and calves. The coefficients of determination for calibration (RSQ) were employed to evaluate the calibration of the predictive equations. Calibration results for cows (dry matter [DM], RSQ = 0.98; crude protein [CP], RSQ = 0.93; ether extract [EE], RSQ = 0.91; neutral detergent fiber [NDF], RSQ = 0.82; acid detergent fiber [ADF], RSQ = 0.89; ash, RSQ = 0.84) and calves (DM, RSQ = 0.92; CP, RSQ = 0.89; EE, RSQ = 0.77; NDF, RSQ = 0.76; ADF, RSQ = 0.92; ash, RSQ = 0.97) demonstrated that NIRS is a cost-effective and efficient alternative for assessing the chemical composition of dairy cattle feces. This provides a new method for rapidly predicting fecal chemical content in cows and calves.

Escherichia coli is a common cause of mastitis in dairy cows, which results in large economic losses to the livestock industry. The aim of this study was to investigate the prevalence of E. coli in raw milk in China, assess antimicrobial drug susceptibility, and identify key antibiotic resistance genes carried by the isolates. In total, 350 raw milk samples were collected from large-scale farms in 16 provinces and cities in six regions of China to assess the resistance of E. coli isolates to 14 antimicrobial drugs. Among the isolates, nine resistance genes were detected. Of 81 E. coli isolates (23.1%) from 350 raw milk samples, 27 (33.3%) were multidrug resistant. Antimicrobial susceptibility testing showed that the 81 E. coli isolates were resistant to 13 (92.9%) of the 14 antibiotics, but not meropenem. The resistance gene blaTEM was highly distributed among the 27 multidrug-resistant isolates with a detection rate of 92.6%. All isolates carried at least one resistance gene, and 19 patterns of resistance gene combinations with different numbers of genes were identified. The most common gene combinations were the one-gene pattern blaTEM and the three-gene pattern blaTEM-blaPSE-blaOXA. The isolation rate of E. coli in raw milk and the identified resistance genes provide a theoretical basis for the rational use of antibiotics by clinical veterinarians.