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Two experiments were conducted on alfalfa to investigate the effects of the addition of commercial chestnut hydrolyzable tannin at ensiling on 1) silage fermentation quality in lab-scale silos and protein degradation in the rumen, and 2) silage fermentation quality and proteolysis in bale silages. Wilted alfalfa was prepared with 4 tannin levels (0, 2, 4, and 6% on a dry matter (DM) basis; T0, T1, T2, T3, respectively) and ensiled in lab-scale silos. Silages (33% DM) were analyzed for fermentation quality, protein rumen degradability in situ, and organic matter digestibility in vitro through gas production after 120 d of conservation. Wilted alfalfa containing 0 and 4% tannin (T0 and T2) was harvested at 40% DM (wilting level I) and 53% DM (wilting level II) for bale (600 mm diameter) silage. Silages were analyzed for fermentation quality after 78 d of conservation. All the silages were well fermented with no butyric acid. Lab-scale silages showed reductions in ammonia, nonprotein nitrogen (NPN) and DM losses in T2 and T3 treatments, while the fermentation acid profiles were unaffected. In experiment 1, the untreated silage (T0) had the highest protein degradability after being incubated in the rumen. The addition of tannin reduced crude protein ruminal disappearance in a dose-dependent manner. However, the tannin reduced the organic matter digestibility by 5.1% for all of the tannin addition levels. The tannin positively affected the silage quality in the round bale silages, in particular reducing ammonia and NPN in the lowest wilting level. In both experiments, T2 treatment reduced proteolysis without any influence of DM on the binding reaction and reduced the NPN by 15% in comparison to the control. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of diets with different starch concentrations and fish oil (FO) supplementation on lactation performance, in vivo total-tract nutrient digestibility, N balance, and methane (CH4) emissions in lactating dairy cows. The experiment was conducted as a 4 x 4 Latin square design with a 2 x 2 factorial arrangement: 2 concentrations of dietary starch [low vs. high: 23.7 and 27.7% on a dry matter (DM) basis; neutral detergent fiber/ starch ratios: 1.47 and 1.12], the presence or absence of FO supplement (0.80% on a DM basis), and their interaction were evaluated. Four Italian Friesian cows were fed 1 of the following 4 diets in 4 consecutive 26-d periods: (1) low starch (LS), (2) low starch plus FO (LSO), (3) high starch (HS), and (4) high starch plus FO (HSO). The diets contained the same amount of forages (corn silage, alfalfa and meadow hays). The starch concentration was balanced using different proportions of corn meal and soybean hulls. The cows were housed in metabolic stalls inside open-circuit respiration chambers to allow measurement of CH4 emission and the collection of separate urine and feces. No differences among treatments were observed for DM intake. We observed a trend for FO to increase milk yield: 29.2 and 27.5 kg/d, on average, for diets with and without FO, respectively. Milk fat was affected by the interaction between dietary starch and FO: milk fat decreased only in the HSO diet. Energy-corrected milk (ECM) was affected by the interaction between starch and FO, with a positive effect of FO on the LS diet. Fish oil supplementation decreased the n-6:n-3 ratio of milk polyunsaturated fatty acids. High-starch diets negatively influenced all digestibility parameters measured except starch, whereas FO improved neutral detergent fiber digestibility (41.9 vs. 46.1% for diets without and with FO, respectively, and ether extract digestibility (53.7 vs. 67.1% for diets without and with FO, respectively). We observed a trend for lower CH4 emission (g/d) and intensity (g/kg of milk) with the high-starch diets compared with the low-starch diets: 396 versus 415 g/d on average, respectively, and 14.1 versus 14.9 g/kg of milk, respectively. Methane intensity per kilogram of ECM was affected by the interaction between starch and FO, with a positive effect of FO for the LS diet: 14.5 versus 13.3 g of CH4/kg of ECM for LS and LSO diets, respectively. [ABSTRACT FROM AUTHOR]

Total mixed rations containing corn (CS), whole plant grain sorghum (WPGS), or forage sorghum (FS) silages were fed to 6 primiparous Italian Friesian cows to determine the effects on lactation performance, nutrient digestibility, and N balance. Furthermore, the relationship between in vivo total-tract neutral detergent fiber (NDF) digestibility (ttNDFD) and the ttNDFD derived by the Cornell Net Carbohydrate and Protein System (CNCPS) model was assessed. Cows were assigned to 1 of 3 diets in a replicated 3 x 3 Latin square with 28-d periods. The experimental treatment was silage type and 3 different silages were included in the diets. The diets were formulated to be iso-NDF. Accordingly, each diet was formulated to contain 41.5% CS silage, 36.7% WPGS silage, or 28.0% FS silage, on a DM basis. Starch content was balanced by adding the appropriate amount of corn meal. Separate collection of total urine and feces was performed. Dietary forages were analyzed for in vitro NDF digestibility (6 and 24 h of incubation) to predict fiber digestion rate with 2 NDF pools (digestible and indigestible). Rumen digestibility of the potentially digestible NDF pool was predicted using CNCPS version 6.1, using the in vitro forage fiber digestion rate. The ttNDFD was predicted assuming that intestinal digestibility of the NDF amount escaping rumen digestion was 20%, according to the CNCPS model. Dry matter intake was decreased by approximately 1.8 kg/d in cows fed the FS diet compared with the other diets, probably for the greater particle size of FS diet. Hence, milk yield (kg/d) was lowest for FS (23.6), intermediate for WPGS (24.6), and highest for the CS diet (25.4). Milk urea N (mg/dL) was highest for FS (12.9), intermediate for WPGS (11.9), and lowest for CS (10.7) diet. In vivo ttNDFD (%) was 51.4 (CS), 48.6 (WPGS), and 54.1 (FS); this was probably due to a higher retention time of FS diet in the rumen rather than to a better quality of the FS silage, as confirmed by in situ and in vitro results. Urinary N excretion (% N intake) was highest for FS (31.8), intermediate for WPGS (29.3), and lowest for the CS (27.5) diet. The predicted ttNDFD (37.7, 36.3, and 39.5% for CS, WPGS, and FS, respectively) were lower than the in vivo results. Providing an adequate starch supplementation, whole plant grain sorghum silage can replace corn silage in dairy cows TMR. Forage sorghum silage had rumen NDF digestibility comparable to the other silages; however, it had a negative effect on dry matter intake and milk production, probably due to an inadequate effect of processing. [ABSTRACT FROM AUTHOR]

Condensed tannins (CT) are plant polyphenols that can affect feed digestibility and are potentially able to reduce enteric CH 4 emissions in ruminants. In this in vivo trial with 8 lactating goats, we investigated the effects of 4 levels of inclusion of a commercial CT extract from quebracho (0%, 2%, 4%, and 6% on dry matter basis; CON, Q2, Q4, and Q6, respectively). The experimental design was a repeated 4 × 4 Latin square with 28-d periods (24 d of diet adaptation and 4 d of sample collection) using metabolic cages and 4 open-circuit respiration chambers. The inclusion of CT in the diets did not affect the dry matter intake (DMI) but caused a linear decrease in diet digestibility, with reductions up to -11% for dry matter, -21% for crude protein (CP), -23% for α-amylase- and sodium sulfite-treated neutral detergent fiber corrected for insoluble ash (aNDFom), and -13% for gross energy, when comparing the Q6 and CON diets. However, ruminal total volatile fatty acids (VFA) concentration was not affected by CT, although there were changes in VFA proportions. Milk yield was highest for Q4 (3,371 g/d) and lowest for Q6 (3,066 g/d). In terms of milk composition, CT induced a linear reduction of fat and CP concentrations. The reduction in CP digestibility resulted in a linear reduction in the milk urea level, up to -37% with Q6. Positively, CT linearly reduced the somatic cells count expressed as linear score. The feed efficiency was linearly decreased by CT inclusion. Furthermore, a shift from urinary to fecal nitrogen excretion was observed with CT. The retained nitrogen was always negative (on average -1.93 g/d). The CH 4 yield (on average 19.2 g of CH 4 /kg DMI) was linearly reduced by CT inclusion, up to -18% with Q6. Regarding the CH 4 intensity, CT induced a linear reduction when expressed per kilogram of milk, but not per kilogram of fat and protein-corrected milk. Moreover, the CH 4 production per kilogram of digestible aNDFom was linearly increased by CT. The metabolizable energy intake (MEI) was not affected by the treatments, but the metabolizability (q = MEI/gross energy intake) was reduced as CT inclusion increased. From the results of the present study, it turned out that CT have a negative impact on feed digestibility and feed use efficiency. Condensed tannins can lower CH 4 emissions from ruminants; however, the main mechanism of action is likely the decrease in feed digestibility. Furthermore, CT did not improve the N use efficiency. According to these findings, the positive environmental impacts of CT are only related to the shift from urinary to fecal N excretion., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Eight lactating Italian Friesian cows were housed in individual respiration chambers in a repeated Latin square design to determine their dry matter intake (DMI) and their milk and methane production, as well as to collect the total feces and urine to determine the N and energy balances. Four diets, based on the following forages (% of dry matter, DM), were tested: corn silage (CS, 49.3), alfalfa silage (AS, 26.8), wheat silage (WS, 20.0), and a typical hay-based Parmigiano Reggiano cheese production diet (PR, 25.3 of both alfalfa and Italian ryegrass hay). The greatest DMI was observed for cows fed PR (23.4 vs. 20.7 kg/d, the average of the other 3 diets). The DM digestibility was lower for PR (64.5 vs. 71.7%, the average of the other diets). The highest ash-free neutral detergent fiber digestibility values were obtained for CS (50.7%) and AS (47.4%). In the present study, no differences in milk production were observed between diets, although PR showed a higher milk yield trend. The highest milk urea N concentration (mg/dL) was found for the cows fed the WS diet (13.8), and the lowest was observed for the cows fed AS (9.24). The highest milk urea N concentration for the cows fed WS was also correlated with the highest urinary N excretion (g/d), which was found for the cows fed that same diet (189 vs. 147 on average for the other diets). The protein digestibility was higher for the cows fed the CS and WS diets (on average 68.5%) than for the cows fed AS and PR (on average 57.0%); dietary soybean inclusion was higher for CS and WS than for AS and PR. The rumen fermentation pattern was affected by the diet; the cows fed the PR diet showed a higher rumen pH and decreased propionate production than those fed CS, due to the lower nonfiber carbohydrate content and higher ash-free neutral detergent fiber content of the PR diet than the CS diet. Feeding cows with PR diet increased the acetate:propionate ratio in comparison with the CS diet (3.30 vs. 2.44 for PR and CS, respectively). Cows fed the PR diet produced a greater daily amount of methane and had a greater methane energy loss (% of digestible energy intake) than those fed the CS diet (413 vs. 378 g/d and 8.67 vs. 7.70%), but no differences were observed when methane was expressed as grams per kilogram of DMI or grams per kilogram of milk. The PR diet resulted in a smaller net energy for lactation content than the CS diet (1.36 vs. 1.70 Mcal/kg of DM for the PR and CS diets, respectively). Overall, our research suggests that a satisfactory milk production can be attained by including different high-quality forages in balanced diets without any negative effect on milk production or on the methane emissions per kilogram of milk., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

The aim of the present study was to evaluate, through a survey conducted on commercial farms, the global warming potential (GWP) of different lactating cow total mixed rations (TMR) and to identify the best dietary strategies to increase feed efficiency (FE) and reduce enteric CH 4 emission. A total of 171 dairy herds were selected: data about dry matter intake (DMI), lactating cow TMR composition, and milk production and composition were provided by farmers. Diet GWP (kg of CO 2 equivalents; CO 2 eq) was calculated as sum of GWP (kg of CO 2 eq) of each included ingredient, considering inputs needed at field level, feed processing, and transport. For soybean solvent meal, land use change was included in the assessment. Enteric methane production (g/d) was estimated [using the equation CH 4 (g/d) = 2.54 + 19.14 × DMI] to calculate CH 4 emission for kilograms of fat- and protein-corrected milk (FPCM). The data set was analyzed by generalized linear model and logistic analysis using SAS 9.4 (SAS Institute Inc., Cary, NC). The frequency distribution showed wide variation among farms for GWP (kg of CO 2 eq) of TMR: approximately 25% of the surveyed farms showed a diet GWP of 15 kg of CO 2 eq, 20% showed a GWP of 13 kg of CO 2 eq, and 16.7% showed a GWP of 17 kg of CO 2 eq. The variation among farms was due to the feedstuffs used. Among feedstuffs, soybean meal (SBM) had the highest correlation with the GWP of the TMR as shown by the following equation: TMR GWP (kg of CO 2 eq) = 2.49 × kg of SBM + 6.9 (R 2 = 0.547). Moreover, diets with inclusion of SBM >15% of dry matter (DM) did not result in higher milk production than diets with a lower inclusion of SBM (≤15%). Average daily milk production of cows was 29.8 [standard deviation (SD) 4.83] kg with fat and protein contents of 3.86% (SD 0.22) and 3.40% (SD 0.14), respectively. The average DMI (kg/d) of lactating cows was 22.3 (SD 2.23). Logistic analysis demonstrated that corn silage ≤30% of diet DM was associated with higher FE. Almost 50% of farms had an average value of 15.0 g of CH 4 /kg of FPCM and about 30% of farms had an average of 12.5 g of CH 4 /kg of FPCM. The results demonstrated that lower enteric CH 4 production was related to inclusion (% of diet DM) of ≤12% alfalfa hay and >30% corn silage. Diets with >34% neutral detergent fiber had higher CH 4 production (>14.0 g/kg of FPCM) than those with lower neutral detergent fiber content. In contrast, lower enteric CH 4 production (≤14.0 g/kg of FPCM) was related to diets characterized by net energy of lactation (NE L ) >1.61 Mcal/kg and >4% ether extract. The variability in TMR GWP shows significant potential for reducing the GWP of a diet through choice and inclusion levels of ingredients (mainly SBM) and the possibility of decreasing methane enteric emission associated with milk production on a commercial scale., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The effect of alfalfa ensiled in bunker silos at high moisture [HM, 34% dry matter (DM)] and low moisture (LM, 56% DM) content on milk production and Grana Padano cheese quality was studied. Forty Italian Friesian lactating cows were allotted to two groups and fed, in a crossover design experiment, two corn silage-based diets containing 27% of the total DM as HM or LM. Each of the two periods included 10 d of adaptation and 3 experimental weeks. Forage was cut in the mid-vegetative stage with, on average, 34% neutral detergent fiber and 19% crude protein (DM basis). The two alfalfa silages showed a different fermentation pattern with 4.04 and 1.25% of lactic acid, 1.95 and 0.42% of acetic acid, 9.1 and 4.8% of total N ammonia-N for HM and LM, respectively. No butyric acid was found. Clostridial spores and yeast showed no growth in both silages except in the first 2 wk of the experiment where slight aerobic deterioration occurred. The HM treatment resulted in slightly lower DM intake (19.3 vs. 19.9 kg/d) and milk protein content (3.33 vs. 3.38%), higher milk fat content (3.56 vs. 3.37%), and 4% fat-corrected milk (25.7 vs. 24.4 kg/d). Totally, 38 cheeses obtained from over 19 tons of milk with an average yield efficiency of 6.8%, were produced. The milk renneting and microbiological properties and the cheese quality were not significantly different between treatments. However, both treatments had on average 40% of low quality (butyric fermentation) cheeses observed mainly in the first 2 wk of the experiment, when the number of clostridial spores found in alfalfa silages was significantly higher than in the subsequent weeks. The data obtained suggest that the microbial quality of milk depends more on careful management and monitoring all of the steps in milk production, from silage harvest through to cheese making, than on the moisture level of alfalfa silage, provided that the latter is in a range of 35 to 55% DM.

The objective of the experiment was to compare a silage-based control diet (C) with a nonforage diet (NF) in dairy goats throughout lactation in terms of animal performance and energy utilization. Eight Saanen goats were divided into two groups and fed C or NF, a commercial blend that included sunflower meal, cassava, coconut meal, and whole cottonseeds as the main ingredients that was characterized by a small particle size and a high crude protein content. In early, mid, and late lactation (44, 100, and 219 days in milk) the goats were individually tested for dry matter intake (DMI), digestibility, milk yield and composition, milk renneting properties, rumen and plasma parameters, and nitrogen and energy utilization (open circuit respiration chambers). During early and mid lactation, the NF fed goats had a very high DMI: 2946 and 2915 g/d, respectively. Nevertheless, milk yield was similar for the two treatments: 4369 vs. 4342 and 3882 vs. 3841 g/d for goats fed diets C and NF during the first and second periods, respectively. Milk fat content was not statistically different between the two diets. The protein content and rheological parameters of milk were similar for the two diets. Nonprotein nitrogen and urea levels in milk of goats fed NF were significantly higher than goats fed C. Ruminal ammonia and plasma urea nitrogen were also significantly increased by diet NF, due to its high protein content. Plasma glucose, beta-hydroxybutyrate, and nonesterified fatty acids and ruminal volatile fatty acids were not influenced by dietary treatment. Dietary NF significantly decreased energy digestibility (74.5 vs. 65.8%, on average for the lactation, for C and NF, respectively) and had a significantly lower metabolizability (metabolizable energy/intake energy; 66.6 vs 58.0%, on average); however, the efficiency of utilization of metabolizable energy was unaffected by the diet. In conclusion, goats were fed a nonforage diet during the entire lactation without detrimental effect on their health and productive performance.