The use of exogenous enzymes in the nutrition of dairy cows is an innovative and efficient strategy to maximize productivity and milk quality, with positive applications in the economic and environmental aspects of dairy farming. Therefore, the objective of this study was to evaluate whether the addition of a blend of exogenous enzymes to the diet of lactating Jersey cows has a positive effect on productive performance, milk quality, animal health, ruminal environment, and digestibility. Twenty-one primiparous Jersey cows, with 210 days in lactation (DL), were used. The exogenous enzymes used were blends containing mainly protease, in addition to cellulase, xylanase, and beta-glucanase. The animals were divided into three groups with seven replicates per group (each animal being the experimental unit), as follows: Control (T-0), basal diet without enzyme addition; Treatment (T-80), animals fed enzymes in the diet at a daily dose of 80 mg per kg of dry matter (DM); Treatment (T-160), animals fed enzymes in the diet at a daily dose of 160 mg per kg of DM. The study lasted 84 days, during which higher milk production was observed in the treated groups (T-80 and T-160) compared to the control group (p = 0.04). When calculating feed efficiency from days 1 to 84, greater efficiency was observed in both groups that received the blend compared to the control (p = 0.05). In the centesimal composition of the milk, it was observed that the percentage of protein in the milk of the T-160 group was higher compared to the control group (p = 0.03). The effect of the enzymes was verified for butyric (p = 0.05) and palmitic (p = 0.05) fatty acids. We also observed the effect of the enzyme blend on the amount of volatile fatty acids (VFAs), which were higher in the ruminal fluid of cows that received the enzymes (p = 0.01). Cows that consumed enzymes showed a higher apparent digestibility coefficient of crude protein (p = 0.01). In vitro, the main result is related to lower gas production in 24 and 48 h at T-160. We concluded that the use of a blend of exogenous enzymes in the diet of lactating Jersey cows was able to increase milk production in these animals, resulting in greater feed efficiency and also an increase in milk protein content, positively modulating the fatty acid profile in the rumen and improving the apparent digestibility of nutrients.

Rumination monitoring assesses dairy cows’ health, reproduction, and welfare status. The present study evaluated whether increasing the milking frequency affects dairy cows’ milk yield and daily rumination profile. The database was obtained from cows monitored using collars equipped with a rumination sensor. Cows were milked two (n = 9 and 379 cows) or three (n = 14 and 704 cows) times daily. Increased milking frequency improved (P ≤ 0.05) milk yield from 36.0 to 41.6 kg/cow/d. However, the milking frequency did not affect (P > 0.05) daily rumination or the proportion of diurnal rumination. Diurnal rumination (from 7 to 19 h) generally represents 46.3% of daily rumination. Cows milked twice daily showed a significant decrease in rumination rate, especially during the second daily milking, compared to cows milked three times daily. Thus, milking frequency affects milk yield and reduces rumination during milking. However, it does not affect daily rumination and the proportion of diurnal rumination and can be used as an acidosis marker regardless of milk frequency.

The objective of this study was to evaluate whether the addition of fibrolytic enzymes to the diet of cattle in confinement improves feed digestibility weight gain; as well as evaluating the profile of fatty acids in the ruminal environment and in meat fatty acids profile. In total, 24 male dairy cattle (Holstein) aged 8 months and weighing an average of 212 kg, were divided into 2 groups: control (without additive) and treatment (0.25 g of enzymes/kg of dry matter of total diet). The experiment lasted 120 days. The first 20 days are allocated for the adaptation period. During the study, samples of blood, ruminal fluid, and feces were collected, as well as weighing the cattle and measuring their daily feed consumption. There was no effect of treatment on body weight, feed intake, feed efficiency, and nutrient digestibility (p > 0.05). Cholesterol levels were higher in the serum of cattle that consumed the enzyme; serum amylase activity was higher in cattle that received the additive only on day 120 of the experiment (p < 0.05). There was a greater amount of volatile fatty acids in the ruminal fluid, combined with a greater amount of acetic acid. The amount of fat in the meat of cattle that consumed fibrolytic enzymes was higher compared to the control group (p < 0.05). Meat from cattle in the treatment group had lower amounts of saturated fatty acids and higher amounts of unsaturated fatty acids (p < 0.05). The fibrolytic enzymes addition altered rumen fermentation in such a way that lipid metabolism was changed, which had a serious impact on cholesterol and tissue levels, that is, in the meat that had a greater amount of total lipids, an unsaturated fat.

Ruminant production in the Chaco region relies on pastures and native forest foliage, whose nutritional value is poorly characterized and may be influenced by tannins. This study evaluated the in situ digestibility and in vitro ruminal fermentation of foliage from Prosopis affinis (PA), Prosopis nigra (PN), Acacia polyphylla (AP), Phyllostylon rhamnoides (PR), and Tabebuia nodosa (TN), incubated with or without polyethylene glycol (PEG) to assess the effects of tannin on gas production and nitrogen (N) compounds degradability. Foliage contained ≥17% crude protein (CP) and ≥40% fiber-bound N. Tannin concentration was >4% dry matter (DM) in PN and PA and <1% DM in PR, AP, and TN. In situ digestibility was ≤51% in all species except PR (73%; p < 0.05). Gas production was higher in PA, PR, and TN (p < 0.05), with no PEG effect. Methane production was not affected by tree species or PEG (p ≤ 0.277). Both species and PEG affected the effective N compounds degradability (END), with PEG increasing it in PN and AP (p < 0.05). Although foliage is high in CP, its digestibility is low; N is largely fiber-bound, and tannins may further limit END, factors to consider when including them in ruminant diets.

Ruminant production in the Chaco region relies mainly on pastures and naturally available foliage from native forests. However, the nutritional value of this foliage remains poorly characterized and may be affected by tannins. This study evaluated the nutritional value, and tannin effects on in vitro ruminal fermentation of foliage from tree species of the Chaco region: Prosopis affinis (PA), Prosopis nigra (PN), Acacia polyphylla (AP), Phyllostylon rhamnoides (PR), and Tabebuia nodosa (TN). Samples were incubated with or without polyethylene glycol (PEG) to assess tannin effects on gas production and nitrogen (N) degradability. All species were high in crude protein (CP; ≥17% DM). Tannin content was high in PN and PA (>4% DM), and low (<1% DM) in PR, AP, and TN. In situ digestibility was low (≤51%) in all species except PR (73%; p < 0.05). Gas production was higher in PA, PR, and TN (p < 0.05), with no PEG effect. Both species and PEG affected the effective N degradability, with PEG significantly increasing it in PN and AP (p < 0.05). Although foliages are high in CP, their digestibility is generally low, much of the N is fiber-bound, and tannins may further limit N degradability.