Effect of citrus pulp silage feeding on concentration of beta‐cryptoxanthin in plasma and milk of dairy cows

Citrus pulp is known to contain a functional molecule of beta‐cryptoxanthin which is one of the carotenoids showing anti‐oxidative capacity. Influences of citrus pulp silage feeding to dairy cows on beta‐cryptoxanthin concentration in plasma, other blood properties and milking performances were investigated. Four Holstein cows were fed total mixed ration (TMR) containing citrus pulp silage 20% dry matter (DM) for 2 weeks with free access to the TMR. Dry mater intake, milk production and milk components 2 weeks later were not altered compared with those of the control group without citrus pulp silage. Activities of aspartate aminotransferase, alanin aminotransferase and gamma‐glutamyltranspeptidase in plasma were not affected by feeding of citrus pulp silage. Concentrations of protein, albumin, sulfhydryl residue, ascorbic acid, thio‐barbituric acid reactive substance and urea nitrogen in plasma were also not altered by citrus pulp silage feeding. Concentration of beta‐cryptoxanthin in plasma was increased approximately 20‐fold compared with the control group (P < 0.05). Content of beta‐cryptxanthin in pooled milk fat fraction was also increased approximately three times compared with that of the control group. Feeding of TMR containing citrus pulp silage 15% DM for 30 days to eight dairy cows also increased plasma beta‐cryptoxanthin concentration 30‐fold compared with that before feeding.     

不同粗饲料组合混合日粮对奶牛泌乳性能的影响

本试验通过给奶牛饲喂不同粗饲料组合的TMR日粮,探讨日粮中不同粗饲料组合对奶牛泌乳性能的影响.结果表明,日粮鲜重的精粗比从30∶70提高到40∶60后,奶牛的干物质采食量有显著地增加（P＜0.05）.随着精料比例增加,其能量水平、蛋白含量和乳蛋白率增加.同时,蛋白含量和产奶量都有所提高.在试验二组中用青贮代替了全贮,提高了奶牛的采食量和泌乳性能.说明,奶牛全混合日粮（TMR）可以提高日粮养分表观消化率、产奶量和改善乳蛋白质水平.青贮饲料的蛋白质的降解和利用更容易被瘤胃微生物降解和吸收,从而提高奶牛的泌乳性能,取得较高的经济效益.     

Studies on the use of lucerne silage source for high-milk-producing dairy cows

Studies on the use of lucerne silage as a forage source for high-yielding dairy cows. It was the main objective of this study to investigate effects of lucerne silage inclusion in maize silage-based rations on dry matter intake, milk yield and metabolic parameters of high yielding dairy cows. Three total mixed rations (TMR) were used. They contained as the main forage source on a dry matter basis 41.5% maize silage and 12% grass silage (ration maize) or 18% maize silage and 29% of either grass silage (ration grass) or lucerne silage (ration lucerne). Organic matter digestibility, determined with wether sheep, was 77 and 65% for the grass and the lucerne silage, respectively. Each TMR was fed to 4 wether sheep to determine crude nutrient digestibilities. The content of net energy for lactation (NEL), as calculated from digestible crude nutrients, was (MJ/kg dry matter (DM)): 7.1 (maize), 7.2 (grass) and 6.8 (lucerne). Based on the results of a chemical fractionation of crude protein it was calculated that the content of utilisable crude protein (nXP) was not below 167 g/kg DM and that the N balance in the rumen was not negative for all 3 TMR. The TMR were fed for 169 days to at least 28 dairy cows per treatment which were in their first half of lactation. Feed intake, milk performance data and physiological indicators were measured for each individual cow. The DM intake was significantly higher in treatment lucerne (23.2 kg/d) than in treatments grass (21.2 kg/d) and maize (22.6 kg/d). Daily intakes of NEL and nXP were significantly lower in treatment grass than in the other two treatments. Milk yield was significantly higher in treatment maize (41.7 kg/d) than in treatments grass (37.3 kg/d) and lucerne (38.5 kg/d). This was associated with a significantly lower milk fat content in treatment maize (3.5%) in comparison with the other two treatments (3.9% each). Milk protein content was unaffected by treatment (3.4% on average). Similarly, the acetone content of milk was not significantly different between treatments. The beta-hydroxybutyrate content of the deproteinized blood was significantly higher in treatment lucerne at start of lactation, but this difference disappeared in subsequent parts of the experimental period. Measurements of back fat thickness indicated mobilisation and retention of energy by cows during the experimental period to be similar in all treatments. It is concluded that lucerne silage is a suitable forage source for high yielding dairy cows in spite of its low digestibility.     

Effect of replacing corn with brown rice grain in a total mixed ration silage on milk production,ruminal fermentation and nitrogen balance in lactating dairy cows

Nine multiparous Holstein cows were used in a replicated 3 × 3 Latin square design to determine the effects of substituting corn grain with brown rice (BR) grain in total mixed ration (TMR) silage on milk yield, ruminal fermentation and nitrogen (N) balance. The TMR silages were made from the ensiling of TMR containing (dry matter basis) 50.1% forage in rice silage and corn silage combination, and 49.9% concentrate. The grain portion of the diets contained 31.2% steam‐flaked corn, 31.2% steam‐flaked BR or an equal mixture of corn and BR. Dietary treatments did not affect dry matter intake, milk yield and milk fat, protein and lactose yields. The ruminal pH and total volatile fatty acid concentrations were not affected by dietary treatment. The urinary N excretion decreased linearly (P < 0.01) in response to increased levels of BR, with no dietary effect on N intake, N secretion in milk and fecal N excretion. Our results indicate that steam‐flaked BR is a suitable replacement for steam‐flaked corn in dairy cow diets, and that it can be included in rations to a level of at least 31.2% of dry matter without adverse effects on milk production, when cows were fed rice silage and corn silage‐based diets.     

裹包TMR饲喂对泌乳中期奶牛生产性能、养分表观消化率及血液生化指标的影响

为了研究裹包全混合日粮(TMR)饲喂方式对泌乳奶牛生产性能、养分表观消化率和血液指标的影响,本试验选择24头泌乳天数为(124±20)d的荷斯坦奶牛,随机分为2个处理组,进行为期10周的饲养试验。对照组采用传统的精粗分开饲喂方式,试验组采用裹包TMR饲喂方式,精粗分开饲喂组和裹包TMR饲喂组的日粮配方组成和比例均相同,日粮精料比例为50∶50,裹包TMR水分含量调整为50%。结果表明,1)饲喂裹包TMR,可以显著增加干物质采食量(P<0.05),提高产奶量7.69%并提高3.5%标准乳产量5.20%(P>0.05);2)裹包TMR饲喂方式与精粗分开饲喂方式对乳成分含量和产量的影响差异不显著;3)裹包TMR饲喂可以显著提高粗蛋白和粗脂肪的表观消化率(P<0.05),干物质消化率有提高的趋势(P<0.1);4)裹包TMR饲喂显著降低了血清中尿素氮的含量(P<0.05),但对其他血液指标影响2组间差异不显著。裹包TMR技术可以作为一种有效的全混合日粮供给方式,可在我国中小规模奶牛养殖场和个体养殖户中推荐使用,以期提高奶牛生产性能和综合收益。     

Milk production,nutrient digestibility and nitrogen balance in lactating cows fed total mixed ration silages containing steam‐flaked brown rice as substitute for steam‐flaked corn,and wet food by‐products

The objective of this study was to evaluate the effect of substituting brown rice grain for corn grain in total mixed ration (TMR) silage containing food by‐products on the milk production, whole‐tract nutrient digestibility and nitrogen balance in dairy cows. Six multiparous Holstein cows were used in a crossover design with two dietary treatments: a diet containing 30.9% steam‐flaked corn (corn TMR) or 30.9% steam‐flaked brown rice (rice TMR) with wet soybean curd residue and wet soy sauce cake. Dietary treatment did not affect the dry matter intake, milk yield and compositions in dairy cows. The dry matter and starch digestibility were higher, and the neutral detergent fiber digestibility was lower for rice TMR than for corn TMR. The urinary nitrogen (N) excretion as a proportion of the N intake was lower for rice TMR than for corn TMR with no dietary effect on N secretion in milk and fecal N excretion. These results indicated that the replacement of corn with brown rice in TMR silage relatively reduced urinary N loss without adverse effects on feed intake and milk production, when food by‐products such as soybean curd residue were included in the TMR silage as dietary crude protein sources.     

Milk Production in High Producing Dairy Cows as Influenced by Corn Silage Quality

Greater milk production is the promised outcome for selecting corn hybrids with various traits that impact forage quality. Our objective was to select a set of hybrids most likely to exhibit differences in forage quality and evaluate milk production of cows fed a high forage diet. Four hybrids were selected for the feeding trial: a leafy hybrid (Mycogen TMF 100®; Mycogen Seeds, Indianapolis, IN), a brown midrib (BMR) hybrid (Mycogen BMR F407®), and two conventional hybrids varying in fiber digestibility (Pioneer 36B08® [Conventional 1 {CONV1}] and Pioneer 35P12® [Conventional 2 {CONV2}]; Pioneer Hybrid International, Inc., Des Moines, IA). Diets were formulated to provide 1.0% BW as forage NDF (approximately 32% NDF) and were balanced to meet or exceed NRC requirements. Fifty-six cows were fed for 56 d. The DMI of cows fed the BMR and the leafy hybrid total mixed rations (TMR) were greater than those of cows fed the other hybrids. Differences in milk production reflected the differences in intake. Cows fed the BMR (41.7 kg/d) and leafy hybrid (42.1 kg/d) TMR were not different from each other in milk production, but had greater (P<0.05) milk production than cows fed CONV1 (39.0 kg/d) or CONV2 (39.2 kg/d) hybrids. Greater intake by cows fed the BMR TMR than by cows fed the CONV1 or CONV2 TMR is likely the result of greater digestibility. Although the leafy hybrid TMR tended to be greater in digestibility than CONV1 or CONV2 TMR, it is likely that a lesser forage-to-concentrate ratio of the leafy hybrid TMR compared with the other TMR also contributed to its greater intake. Ruminal concentrations of propionate were greater in cows fed BMR than in those fed other hybrids, which could also result in greater milk production. Corn silage hybrids selected for improved forage quality can result in greater milk production by cows fed the improved hybrids in high forage diets.     

Oats (Avena strigosa) as winter forage for dairy cows in Vietnam: an on-farm study

In North Vietnam, during winter, alternative forage resources are needed to balance the feed ration of dairy cows. The objective of this study was to investigate the effect of oat forage as a component of traditional winter roughage diets on feed intake, milk production and feeding cost in dairy cows. The study was conducted on-farm using 24 mid-lactation Holstein–Friesian cows. The feeding experiment consisted of two successive periods and two dietary treatments per period. Traditional basal diets included fresh tropical grasses, maize silage and hay. The oat forage had no effect on the dry matter intake of the basal diet, but the total crude protein intake was higher in cows fed with oat diets than in those fed with control diets. The yield of butterfat-corrected milk (FCM) was not significantly different between diets during period 1, but there was a trend (P?=?0.078) of higher FCM yields in cows fed with the oat diet compared to those with control diet during period 2 (17.3 vs. 16.3 kg/day). The decline rate in milk yield was significantly higher (P?<?0.001) in cows fed with control diets than in those fed with oat diets in both experimental periods. The total feeding cost of cows fed with oat diets was on average 12 % lower than those fed with control diets (P?<?0.01). So, the oat forage is an important winter resource for cows in North Vietnam allowing higher milk yield whilst reducing feeding cost, compared to traditional roughage diets.     

不同方式处理的全株玉米青贮对奶牛生产性能和经济效益的影响

[目的]探究不同方式制备的全株玉米青贮饲喂奶牛后,对其生产性能和经济效益的影响。[方法]选定中国荷斯坦牛开展全株玉米青贮饲喂试验。将28头奶牛随机分为对照组和试验组,每组14头。前者饲喂不添加菌剂制备的全株玉米青贮,后者饲喂添加青贮菌剂制备的全株玉米青贮。统计各组奶牛日均干物质采食量、日均产奶量、料重比、乳脂率和乳蛋白率,计算各组奶牛日均经济效益和试验期总经济效益。[结果]采用添加青贮菌剂制备的全株玉米青贮饲喂奶牛后,奶牛日均干物质采食量和料奶比与对照组差异不显著,但日均产奶量、平均乳脂率和乳蛋白率显著提高（P<0.05）。每头牛日均产奶量增加1.91 kg,乳脂率增加0.22个百分点,乳蛋白率增加0.06个百分点。试验组经济效益明显提高,每头牛日均经济效益增加4.73元,正试期内总经济效益增加1 986.60元。[结论]采用添加青贮菌剂的全株玉米青贮饲喂奶牛,能有效提高奶牛的生产性能和经济效益。     

苜蓿青贮对低质粗饲料条件下奶牛产奶性能的影响

选择1～3胎次泌乳中期的荷斯坦牛10头,配对分为2组:对照组和试验组,两组的混合精料组成相同,对照组粗饲料为豆秸、玉米秸、花生秧和玉米淀粉渣,试验组以10kg苜蓿青贮替代等量粗饲料,进行60d的饲养试验,以研究苜蓿青贮对低质粗饲料条件下奶牛产奶性能的影响。结果表明:(1)添加苜蓿青贮提高了供试奶牛体重(P0.01);(2)试验组各期采食量均高于对照组,且试验60d时差异达到了极显著水平(P0.01);(3)添加苜蓿青贮,提高了供试奶牛的产奶量和乳脂肪含量(P0.01,P0.05)。     

Effects of diets containing alfalfa hay or barley flour mixed alfalfa silage on feeding behavior, productivity, rumen fermentation and blood metabolites in lactating cows

The effects of barley flour on the fermentation parameters of alfalfa silage and on the productivity of dairy cows were investigated. Alfalfa forage was ensiled either with or without barley flour. Barley flour was soaked in water for 24 h before being mixed with alfalfa (12 kg: 100 kg dry matter bases) at ensiling. Eighteen multi-parous cows were assigned to three equal treatment groups using a completely randomized design. Three isocaloric and isonitrogenous total mixed rations containing alfalfa hay, ordinary alfalfa silage or barley flour mixed alfalfa silage were then prepared. The concentrations of ammonia nitrogen, acetic acid and butyric acid were lower in barley flour mixed alfalfa silage compared to that in ordinary alfalfa silage but the concentration of lactic acid was lower in the ordinary alfalfa silage. Feeding behavior, milk yield and composition, ruminal fermentation and blood metabolites were measured. Although dry matter intake and milk production were not affected, the effect of preparation of alfalfa influenced feeding behavior and rumen fermentation parameters. Cows on alfalfa silage diets spent longer ruminating compared to those fed alfalfa hay. The ruminal ammonia nitrogen and blood urea were affected by ensiling (alfalfa hay versus alfalfa silages) while both parameters were lower in cows fed on barley flour mixed alfalfa silage than those fed on ordinary silage. Although similar blood glucose was recorded for cows fed on alfalfa silages, it was higher in cows fed on alfalfa hay. It is concluded that the addition of barely flour when making alfalfa silage may improve both the fermentation process during ensilage and the ruminal ammonia nitrogen utilization with no significant effects on productivity.     

Dry matter intake and milk production of grazing dairy cows supplemented with corn silage or a total mixed ration offered ad libitum in a subtropical area

This study aimed to evaluate the feeding choice, dry matter (DM) intake, and milk production of dairy cows that strip grazed on a mixed perennial species pasture receiving different supplementation strategies. The treatments were without supplementation (WS) or with supplementation of either corn silage (CS) or a total mixed ration (TMR) based on CS and concentrates, in a subtropical area. The supplements were provided ad libitum after the afternoon milking. Twelve Holstein × Jersey cows in mid-lactation (133 ± 43 days in milk) were divided into six groups (two cows/group) and distributed in accordance with a replicated 3 × 3 Latin square design, with three 21 day periods (15 adaptation days and 6 evaluation days). The total DM intake, milk production, milk fat, and milk protein production were greater in the TMR treatment than in the WS and CS treatments and were similar between the WS and CS treatments. The herbage DM intake and proportion of time spent grazing were greater in the CS treatment than in the TMR treatment. CS supplementation did not affect the total DM intake or milk production/cow, whereas TMR supplementation greatly improved the total DM intake and milk production of the dairy cows grazing on mixed perennial species.     

Effects of substituting kraft pulp with corn silage on dry matter intake,ruminal mat formation,rumen fermentation,and rumination activity in non‐lactating cows

The present study examined the effects of substituting kraft pulp (KP) with corn silage (CS) on dry matter intake (DMI), ruminal mat and rumen fermentation characteristics, and rumination. Four non‐lactating, rumen‐cannulated Holstein cows were fed a CS diet comprising 36% grass silage (GS) and 64% CS or a KP diet comprising 36% GS, 57% KP, and 7% soybean meal. DMI was significantly lower in cows fed the KP diet than in those fed the CS diet (p < 0.05), whereas rumination time did not significantly differ between the treatments. Dry matter content in the rumen immediately before and 3 h after feeding was significantly higher in cows fed the KP diet than in those fed the CS diet (p < 0.05). The consistency and thickness of the ruminal mat did not significantly differ between the treatments. The ruminal mean retention time of feed particles tended to be longer in cows fed the KP diet than in those fed the CS diet (p < 0.10). The ruminal digestion rate of KP was comparable to that of GS and CS. Because ruminal mat was formed and rumination was stimulated, KP was considered to have the equivalent physical effectiveness as CS.     

EM发酵玉米秸秆和青贮玉米秸秆对奶牛生产性能的对比试验

本试验应用EM发酵玉米秸秆和青贮玉米秸秆饲喂奶牛,以观察两种方法处理的玉米秸秆对奶牛生产性能及经济效益的影响效果。结果表明,用EM发酵的玉米秸秆饲喂奶牛较青贮玉米秸秆饲喂奶牛,每天每头奶牛采食量提高1.03%,平均产奶量提高2.02%,经济效益提高0.13元;EM原液发酵的玉米秸秆和青贮玉米秸秆1∶1混合饲喂奶牛,每天每头奶牛采食量、平均产奶量、经济效益分别比饲喂青贮玉米秸秆的奶牛提高2.85%、2.99%和1.15元。     

Clostridium botulinum type B toxicosis in a herd of cattle and a group of mules

Clostridium botulinum type B toxicosis was diagnosed as the cause of generalized weakness and death in a group of cows and mules fed from the same batch of rye silage. One severely affected cow was treated and recovered, as did other less severely affected cows. All affected mules died. The remaining cattle in the herd were then vaccinated before continued feeding of the silage.     

Heat production, eating behavior and milk yield of lactating cows fed two rations differing in roughage content and digestibility under heat load conditions

The objective of this study was to measure the effect of feeding two total mixed rations (TMRs), differing in their roughage content and in vitro dry matter digestibility, on the respiratory rate, body temperature, eating behavior and energy balance of lactating cows. The partitioning of metabolizable energy intake (MEI) between heat production (HP) and retained energy (RE) of cows held under heat load conditions was measured. Forty-two lactating cows were divided into two similar sub-groups, each of 21 animals, and were fed either a control (CON) ration containing 18% roughage neutral detergent fiber (NDF) or an experimental (EXP) TMR that contained 12% roughage NDF and used soy hulls as partial wheat silage replacer. The in vitro DM digestibility of the CON and EXP TMRs was 75.3 and 78.6%, respectively (P < 0.05). The EXP diet reduced rectal temperature and respiratory rate of the cows while increasing their number of meals per day by 32.7% as compared with the CON fed cows, and these meals were shorter in duration and were eaten faster. The EXP diet increased total DM intake from 19.6 to 21.5 kg/cow/d, milk yield from 32.3 to 34.6 kg, and yield of energy corrected milk from 30.9 to 32.2 kg, as compared with the CON group. Cows fed the EXP TMR had increased RE in milk and body tissue, as compared with the CON group, but the diets had no effect on the measured HP that was maintained similar (121 vs. 127 MJ/cow/d) in the two groups. The measured MEI (MEI = RE + HP) and the efficiency of MEI utilization for RE production, were similar in the two dietary groups.     

不同全株玉米青贮饲喂量对妊娠期母牛体况、血液指标及后代犊牛的影响

试验旨在研究全株玉米青贮饲喂量及精粗饲料配比对妊娠期母牛体况、血液指标及后代犊牛的影响。选用40头体重相近、2岁、1胎的妊娠期7个月左右的西门塔尔母牛,随机分为4组,每组10头,试验期3个月。Ⅰ组每头每天饲喂全株玉米青贮14 kg、燕麦秸1 kg、精料补充料3 kg,Ⅱ组每头每天饲喂全株玉米青贮19 kg、燕麦秸1 kg、精料补充料1 kg,Ⅲ组每头每天饲喂全株玉米青贮19 kg、燕麦秸2 kg,Ⅳ组每头每天饲喂全株玉米青贮22 kg、燕麦秸1 kg。产犊后各组母牛统一更换为泌乳料,母牛带犊哺乳,6月龄断奶。结果表明:Ⅳ组的干物质摄入量低于Ⅰ组(P<0.05);Ⅲ组和Ⅳ组的氮摄入量低于其他组(P<0.01),Ⅰ组最高(P<0.01);Ⅲ组的纤维摄入量高于其他组(P<0.01);各组体况评分无差异;妊娠期7月末,Ⅳ组血液锰含量低于其他组(P<0.05);妊娠期9月末,Ⅲ组和Ⅳ组的血清尿素氮含量低于其他组(P<0.01);Ⅳ组母牛所产犊牛的胸围低于Ⅰ组和Ⅱ组(P<0.05),且有3头因生长缺陷被淘汰;6月龄时,各组犊牛体况指标无差异。综上,推荐肉牛能繁母牛妊娠后期每日提供全株玉米青贮19 kg、燕麦秸1~2 kg、精料补充料0~1 kg。     

Influence of fibrolytic enzymes in total mixed ration containing urea-molasses-treated sugarcane bagasse on the performance of lactating Holstein–Friesian crossbred cows

The aim of this study was to determine the effect of different levels of fibrolytic enzyme on nutrient utilization and milk production in dairy cows. Four multiparous early-to-mid-lactation Holstein–Friesian crossbred cows were randomly allocated in a 4 × 4 Latin square design. Cows were fed a balanced total mixed ration (TMR) on a dry matter (DM) basis containing 0, 1.2, 2.4, and 3.6 g/kg DM of fibrolytic enzyme in TMR, where the TMR comprises 60% concentrate supplemented with a fibrolytic enzyme at 0, 2, 4, and 6 g/kg DM of concentrate, and 40% urea-molasses-treated sugarcane bagasse (UMSB) was used as a roughage source. Fibrolytic enzyme supplementation in TMR containing UMSB did not affect dry matter intake (DMI) of dairy cows (p > 0.05). There was a quadratic effect of fibrolytic enzyme levels on the digestibility of DM, organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) (p < 0.05), and the maximal response was reached at 1.2–2.4 g/kg DM of fibrolytic enzyme added in the TMR. Furthermore, 3.5% fat-corrected milk, milk fat, total volatile fatty acids, and propionic acid were greater in a cow fed with 1.2–2.4 g/kg DM of fibrolytic enzyme, resulting in a lower ratio of acetic acid to propionic acid (p < 0.05). In conclusion, adding a fibrolytic enzyme in TMR containing UMSB improved nutrient utilization, rumen fermentation, and milk production of lactating dairy cows.     

Milk yield,gross composition and fatty acid profile of dual‐purpose Aosta Red Pied cows fed separate concentrate‐forage versus total mixed ration

This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual‐purpose cattle. Twenty‐four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR‐ and TMR‐fed cows, respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd‐ and branched‐chain FA) and the extent of ruminal biohydrogenation were comparable (P > 0.05) between SR‐ and TMR‐fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied.     

Feeding behavior and ruminal acidosis in beef cattle offered a total mixed ration or dietary components separately

Eighty continental crossbred beef heifers (414.9 ± 37.9 kg of BW), 16 of which were ruminally cannulated, were used in a 52-d experiment with a generalized randomized block design, to assess if self-selection of dietary ingredients modulates ruminal pH and improves rumen function of feedlot finishing cattle. Treatments were total mixed ration [TMR; 85% barley grain (BG), 10% corn silage (CS), 5% supplement]; or free-choice (self-selection; FC) diets of barley grain and corn silage (BGCS), barley grain and wheat distillers grain (BGDG), or corn silage and wheat distillers grain (CSDG). Heifers were housed in groups of 10 in 8 pens equipped with the GrowSafe System (Airdrie, AB, Canada) enabling feed intake and feeding behavior to be continuously monitored. Two cannulated heifers were randomly assigned to each pen and equipped with indwelling pH probes for continuous measurement of ruminal pH during 4 periods (d 1 to 4, d 7 to 14, d 21 to 28, and d 42 to 49). Rumen fluid samples were collected from cannulated heifers on d 7 and 42 before feed delivery, and on d 4 and 49 at 2 h post-feed delivery for determination of VFA. Heifers fed the TMR had shorter (P = 0.01) and smaller (P = 0.03) meals than those fed the FC diets. Cattle fed BGCS and BGDG increased (P < 0.01) intake of BG over time by up to 80 and 70%, respectively. Increased consumption of BG arose from an increase (P < 0.01) in eating rate over the same (P > 0.10) feeding time, which was accompanied by an increase (P < 0.05) in eating rate but a decrease (P < 0.05) in feeding time of either CS or DG. Even with increased BG consumption, ruminal pH and VFA profiles were not different (P > 0.10) among FC diets or compared with the TMR. Cattle fed FC CSDG consumed DG at 60% of dietary DM over the trial, resulting in greater (P < 0.05) mean ruminal pH and acetate-to-propionate ratio and less (P < 0.05) area under the curve than those given the other FC diets or the TMR. Finishing feedlot cattle fed FC diets containing BG self-regulate intake of diets that have a similar composition, intake level, and ruminal fermentation profile to those fed a TMR.