Inclusion Of Alfalfa Hay Research Articles

Milk plane of nutrition and alfalfa hay provision in neonatal Holstein calves: growth performance, ruminal fermentation characteristics, and blood biochemical attributes

Greater nutrient supply through an increased amount of milk and addition of forage to starter may improve the growth rate, rumen development, average daily gain (ADG), and dry matter intake (DMI) of dairy calves. This experiment aimed to study the effect of interaction between milk plane feeding and inclusion of alfalfa hay in starter on the performance, skeletal characteristics, ruminal fermentation and plasma metabolites of dairy calves. Thirty-two 3-d-old Holstein female calves (36.43 ± 2.1 initial BW) were individually housed (n = 8 calves per treatment) and, assigned to 1 of 4 experimental treatment groups in a completely randomized design with a 2 × 2 factorial arrangement. Experimental treatment groups were (1) conventional (COV) milk feeding without forage provision (COV-NF); (2) COV milk feeding with forage provision (COV-F); (3) high milk feeding without forage provision (HM-NF); and (4) high milk feeding with forage provision (HM-F). Calves in the COV and high milk methods received 4 or 8 L/d milk, respectively. Forage-supplemented calves received 15% alfalfa hay mixed with the thoroughly ground starter as a total mixed ration. Calves had ad libitum access to water and starter throughout the study. All calves were weaned at 56 d of age and, the experiment was fulfilled two weeks following the weaning. Individual milk intake and solid feed consumption were recorded daily. The interaction of milk plane nutrition and alfalfa provision was significant for the starter and DM intake, with the greatest starter intake for COV-F treatment and DMI for COV-F and HM-NF treatments during the overall period. The greatest ADG during the pre-weaning and overall period and BW at weaning were observed in HM-NF treatment calves. Calves in the HM-NF treatment had the highest final heart girth; however, other skeletal measurements were not influenced by milk plane feeding and alfalfa provision interaction. No interaction was detected between the milk plane feeding and alfalfa provision for plasma glucose, BUN, BHBA, albumin, total protein, AST and ALT concentrations and rumen fermentation attributes. Regardless of alfalfa provision, pre-weaning starter intake, ADG, feed efficiency (FE), post-weaning starter intake, overall starter intake, FE, weaning BW, body length and hip height, and acetate concentration were increased; whereas, total VFA and valerate concentrations were decreased as milk plane increased. Milk plane feeding and forage inclusion had no effect on diarrhea incidence. It is concluded that independent of alfalfa provision, feeding a higher milk plane improved the performance of dairy calves.

Feeding Models to Optimize Dairy Feed Rations in View of Feed Availability, Feed Prices and Milk Production Scenarios

In the global dairy production sector, feed ingredient price and availability are highly volatile; they may shape the composition of the feed ration and, in consequence, impact feed cost and enteric methane (CH4) emissions. The objective of this study is to explore the impact of changes in feed ingredients’ prices and feed ingredients’ availability on dairy ration composition, feed cost and predicted methane yield under different levels of milk production. To meet the research aim, a series of multi-period linear programming models were developed. The models were then used to simulate 14 feed rations formulations, each covering 162 months and three dairy production levels of 10, 25 and 35 kg milk/d, representing a total of 6804 feed rations altogether. Across milk production levels, the inclusion of alfalfa hay into the feed rations declined from 55% to 38% when daily milk production increased from 10 to 35 kg, reflecting the cows’ increased energy requirements. At a daily milk production level of 35 kg, CH4 production (per kg milk) was 21% and 53% lower than in average and low milk producing cows, respectively, whereas at 10 kg of milk production the potential to reduce CH4 production varied between 0.6% and 5.5% (average = 3.9%). At all production levels, a reduction in CH4 output was associated with an increase in feed costs. Overall, and considering feeding scenarios in low milk producing cows, feed cost per kg milk was 30% and 37% higher compared to that of average and high milk production, respectively. The feed ration modeling approach allows us to account for the interaction between feed ingredients over time, taking into consideration volatile global feed prices. Overall, the model provides a decision-making tool to improve the use of feed resources in the dairy sector.

Soybean oil supplementation and alfalfa hay inclusion in starter feed of Holstein dairy calves: growth performance, digestibility, ruminal fermentation and urinary purine derivatives

Forty newborn Holstein female calves (BW = 39.9 ± 2.1 kg) were assigned to 1 of 4 treatment groups (each consisting of 10 animals) in a 2 × 2 factorial arrangement of supplemental soybean oil [0 vs. 3% soybean oil (SBO) on dry matter basis] and forage level [0 vs. 15% alfalfa hay (AH) on dry matter basis] to evaluate the interaction effect of supplemental fat and forage feeding level in starter feed of dairy calves. Treatments were; (1) neither SBO supplementation nor AH inclusion (NSBO-NAH); (2) SBO supplementation but no AH included (SBO-NAH); (3) no SBO supplementation but AH included (NSBO-AH); and (4) SBO supplementation with AH (SBO-AH). Calves had ad-libitum access to water and starters throughout the study and weaned on day 63 of age but remained in the study until day 73 of age. The results showed that SBO supplementation reduced starter intake, average daily gain (tendency) and faecal consistency compared to un-supplemented diets. The lowest digestibility for neutral detergent fibre and crude protein, as well as the lowest wither height and volatile fatty acid production, were found for SBO-AH diet among experimental treatments. Moreover, the lowest urinary purine derivatives excretion but the highest urinary nitrogen excretion found in SBO-AH diet indicated the lowest nitrogen utilisation efficiency among experimental treatments. In summary, based on the current study condition, because the negative effects of SBO supplementation were exacerbated when AH was incorporated in the starter feed, concurrent feeding of SBO and AH is not recommendable in young calves. HIGHLIGHTS Supplemental soybean oil and alfalfa hay inclusion in starter feed of dairy calves was evaluated. Supplementation of SBO reduced crude protein digestibility and ruminal propionate concentration and caused looser faecal consistency. The inclusion of AH exacerbated the negative effects of SBO supplementation on ruminal fermentation and microbial activity. Concurrent supplementation of SBO and AH inclusion is not recommendable in dairy calves.

Effects of feeding level of alfalfa hay on nitrogen utilization for 1‐kg daily gain of crossbred Simmental male calves

AbstractIn Gansu Province, a key beef cattle production area in China, feeding systems are changing from grazing to stall‐feeding. To reduce production costs, alternative feeding regimens with domestic forages, such as alfalfa hay (AH), are needed. We evaluated the effects of the AH feeding level on nitrogen balance and daily gain (DG) of Simmental calves by two feeding trials. In trial 1, when AH was consumed at 0%–19% of total dry matter intake, no clear effect of AH intake on metabolizable‐protein supply and DG was observed. In trial 2, when more concentrate feed was fed than in trial 1, metabolizable‐protein supply and nitrogen retention increased as the AH consumption rate increased (0%–38% of total intake); these effects appeared to be related to the DG increase. Our results suggest that AH inclusion in concentrate‐based diets increases the metabolizable‐protein supply for the optimal DG of growing beef calves.

Appropriate level of alfalfa hay in diets for rearing Simmental crossbred calves in dryland China.

ObjectiveIn dryland areas of China, alfalfa hay (AH) is a possible substitute for concentrate feed for beef cattle. To evaluate the potential benefits of this substitution, we studied the effect of the ratio of AH intake to total dry matter (DM) intake on average daily body-weight gain (ADG), dietary energy utilization status, and economic benefit in Gansu province.MethodsIn each of two feeding trials in 2016 (trial 1 [T1], July 3 to 17; trial 2 [T2], August 15 to September 23), crossbred male Simmental calves were allocated to low AH (LA), medium AH (MA), and high AH (HA) feeding groups (n = 4 per group). The target ADG was set as 1 kg for both trials. In a one-way-layout design based on conventional feeding practices in the province, calves received diets containing the different AH amounts, with a constant ratio of corn stover:total DM and decreasing rations of concentrate feed proportional to the increase in AH. Calves in T1 received AH at 15% (T1-LA), 23% (T1-MA), or 31% (T1-HA) of their dietary DM allowances; those in T2 received 9% (T2-LA), 24% (T2-MA), or 34% (T2-HA) AH.ResultsAmong the T1 groups, both ADG and economic benefit were highest in T1-LA; whereas in T2, they were higher in the T2-LA and T2-MA groups than in T2-HA. Energy digestibility did not significantly differ among the groups in either trial. The dietary AH inclusion ratios of 14% in the warm season and 8% to 21% in the cool season appeared to yield optimal ADG, metabolizable energy intake, and economic benefit.ConclusionLow-level inclusion of AH, ranging from 8% to 21%, is a practical approach for beef cattle feeding. This modified feeding regimen likely will promote increased growth performance during the fattening stage of beef steers in dryland areas of Gansu province, China.

Effect of increasing the level of alfalfa hay in finishing beef heifer diets on intake, sorting, and feeding behavior.

Eight rumen cannulated Simmental heifers (BW = 281.4 ± 7.28 kg) were randomly assigned to one of four experimental treatments in a 4 × 4 replicated Latin square design to ascertain the effects of increasing levels of alfalfa hay on intake, sorting, and feeding behavior in comparison to barley straw as forage source. Treatments tested were four total mixed rations with: 1) 10% barley straw (10BS) with 7.0% NDF from forage, 2) 13% alfalfa hay (13AH) and less NDF from forage (5.7%) than 10BS, 3) 16% alfalfa hay (16AH) and the same NDF from forage (7.0%) as 10BS, and 4) 19% alfalfa hay (19AH) and more NDF from forage (8.3%) than 10BS. Each experimental period consisted of 3 wk for adaptation and 1 wk for sampling. Increasing the proportion of alfalfa hay in the diet linearly increased (P < 0.05) total DMI, CP intake, water consumption, intake of long, medium and fine particle size, extent of sorting of fine particle size, and time spent rumination, but linearly decreased (P < 0.05) extent of sorting of short particle size. Intake of DM was higher in heifers fed 16AH and 19AH than in heifers fed 10BS (P < 0.001). Intake of NDF and physically effective NDF (peNDF) was greater in 13AH, 16AH, and 19AH than in 10BS (P < 0.01). The DMI of medium and short particle size was greater in 13AH, 16AH, and 19AH than in 10BS (P < 0.05), whereas DMI of long particle size was greater in 16AH and 19AH compared to 10BS (P < 0.001). Heifers fed 13AH, 16AH, and 19AH diets sorted against fine particle size and sorted for or tended to sort for short, medium, and long particle sizes. Meal length was greater in heifers fed 16AH and 19AH than 10BS (P < 0.05). Time spent eating was not affected by diet but time spent ruminating was greater in heifers fed 19AH than in 10BS (P < 0.05). Results indicate that the inclusion of alfalfa hay at 19% of incorporation caused an increase in DM, NDF, and peNDF intake, in comparison to the 10BS diet. In the same way, intake of long, medium, and short particle size was greater in this diet. Moreover, heifers fed 19AH sorted for medium particle size and tended to sort for long and short particles size, and against fine particle size. Sorting behavior and meal length increased in the 19AH diet, which leads us to think that sorting feed ingredients requires time and therefore lengthens the meal. Time spent ruminating was greater in heifers fed 19AH, thus reducing the risk of ruminal acidosis when animals are fed high concentrate diets.

Effects of substituting alfalfa hay for concentrate on energy utilization and feeding cost of crossbred Simmental male calves in Gansu Province, China

AbstractFrom August to September 2015 (trial 1 [T1]) and September to November 2015 (trial 2 [T2]), the effects of replacing concentrate feed (C) with alfalfa hay (AH) on the daily gain (DG), dietary energy utilization status and the economic advantage of AH feeding for growing beef cattle were studied in crossbred male Simmental calves (n = 18) in Gansu Province, China. The target DG was set as 1 kg for both trials. Animals in each trial were allocated to a conventional feeding group (CTRL), a low‐level AH feeding group (LA), and a high‐level AH feeding group (HA). In a one‐way‐layout design, they were fed iso‐energetic experimental diets comprising harvested corn stover (CS) and C (T1‐CTRL, T2‐CTRL), diets replacing 22% (T1‐LA) or 44% (T1‐HA) of the quantity of C for T1‐CTRL with AH, and diets replacing 13% (T2‐LA) or 25% (T2‐HA) of the quantity of C for T2‐CTRL with AH. Measurements of feed intake and DG, respiration and metabolism trials were performed for 49 and 41 days in T1 and T2, respectively. Average DG did not reach the target value for HA in T1 and CTRL in T2. Energy metabolizability was slightly greater for CTRL than for LA and HA in T1 and significantly greater for CTRL than for the other groups in T2. There was no marked difference in energy metabolizability between LA and HA in both trials. Dietary substituting AH for C did not impair the feed intake of the animals, but it did not improve feed efficiency. In terms of economic feasibility, low‐level AH inclusion in the diets of growing beef cattle appeared more profitable at the 1‐kg DG level as compared with CTRL and high‐level AH inclusion, and should be practiced in the drylands of Gansu Province, China.

Interactions of alfalfa hay and sodium propionate on dairy calf performance and rumen development

The objective of this experiment was to investigate the effects of different levels of alfalfa hay (AH) and sodium propionate (Pro) added to starter diets of Holstein calves on growth performance, rumen fermentation characteristics, and rumen development. Forty-two male Holstein calves (40±2kg of birth weight) were used in a complete randomized design with a 3×2 factorial arrangement of treatments. Dietary treatments were as follows: (1) control = concentrate only; (2) Pro = concentrate with 5% sodium propionate [dry matter (DM) basis]; (3) 5% AH = concentrate + 5% alfalfa hay (DM basis); (4) 5% AH + Pro = concentrate + 5% alfalfa hay + 5% sodium propionate (DM basis); (5) 10% AH = concentrate + 10% alfalfa hay (DM basis); and (6) 10% AH + Pro = concentrate + 10% alfalfa hay + 5% sodium propionate (DM basis). All calves were housed in individual pens bedded with sawdust until 10wk of age. They were given ad libitum access to water and starter throughout the experiment and were fed 2L of milk twice daily. Dry matter intake was recorded daily and body weight weekly. Calves from the control, 10% AH, and 10% AH + Pro treatments were euthanized after wk 10, and rumen wall samples were collected. Feeding of forage was found to increase overall dry matter intake, average daily gain, and final weight; supplementing sodium propionate had no effect on these parameters. Calves consuming forage had lower feed efficiency than those on the Pro diet. Rumen fluid in calves consuming forage had higher pH and greater concentrations of total volatile fatty acids and molar acetate. Morphometric parameters of the rumen wall substantiated the effect of AH supplementation, as plaque formation decreased macroscopically. Overall, the interaction between forage and sodium propionate did not affect calf performance parameters measured at the end of the experiment. Furthermore, inclusion of AH in starter diets positively enhanced the growth performance of male Holstein calves and influenced both the macroscopic and microscopic appearances of the rumen wall. These benefits, however, were small when only sodium propionate was offered.

Interactive effects of bulk density of steam-flaked corn and concentration of Sweet Bran on feedlot cattle performance, carcass characteristics, and apparent total tract nutrient digestibility1

Two hundred twenty-four steers (initial BW = 363 ± 1.57 kg) were used in a 2 × 3 + 1 factorial arrangement of treatments to evaluate the interactive effects of concentration of wet corn gluten feed (WCGF) and bulk density (BD) of steam-flaked corn (SFC) on feedlot performance, carcass characteristics, and apparent total tract digestibility. Diets consisted of 0, 15, or 30% WCGF (DM basis) with a BD of SFC at 283 or 360 g/L. The additional treatment consisted of 15% WCGF, SFC at 283 g/L, and a 6% inclusion of alfalfa hay vs. 9% for all other treatments. Steers were fed once daily for an average of 163 d. During a 5-d digestion period, DMI was measured, and fecal samples were collected for measurement of nutrient digestibility using dietary acid insoluble ash as a marker. There were few WCGF × BD interactions for feedlot performance, carcass characteristics, and digestibility. Similarly, contrasts between the treatment containing 15% WCGF/360 g/L SFC and 15% WCGF/360 g/L with 6% hay yielded few differences for performance and carcass data. Final BW responded quadratically (P ≤ 0.02) to WCGF inclusion and showed increased (P ≤ 0.007) BW for greater BD. As WCGF inclusion increased, G:F and calculated NE values (P ≤ 0.03) decreased quadratically. Steers consuming 360 g/L SFC had greater (P < 0.05) G:F than those fed 283 g/L SFC. Marbling score, HCW, 12th-rib fat thickness, and calculated yield grade increased quadratically (P ≤ 0.04) with increased inclusion of WCGF. Percentage of cattle grading premium Choice or greater responded quadratically (P = 0.04) to WCGF concentration. Increasing BD increased (P ≤ 0.01) HCW, dressing percent, marbling score, and 12th-rib fat thickness and decreased calculated yield grade and percentage of cattle grading Select; however, lower BD tended (P = 0.09) to increase LM area. Intake of DM, OM, CP, and NDF and fecal output during the digestibility period increased linearly (P ≤ 0.01) with increasing WCGF, and greater BD increased (P ≤ 0.04) intake of DM, OM, starch, and CP. Starch digestibility decreased quadratically (P = 0.008) as WCGF increased; however, digestibility of CP and NDF increased (P ≤ 0.02) linearly as WCGF increased. The 283 g/L BD increased (P ≤ 0.02) starch and CP digestibility compared with 360 g/L. These data suggest that increasing WCGF in feedlot diets with a greater BD of SFC can increase performance and carcass characteristic, but it might not be ideal for starch digestibility.

Effects of decreased dietary roughage concentration on energy metabolism and nutrient balance in finishing beef cattle1

The optimal roughage concentration required in feedlot diets changes continuously for many reasons such as source, availability, price, and interaction with other ingredients in the diet. Wet distillers grains and solubles (WDGS) are common in finishing diets and they contain relatively high amounts of fiber compared with other grains they replace. Therefore, concentration of roughage could be altered when WDGS are included in feedlot diets. There has been very little data published regarding the effects of roughage concentration on energy metabolism and nutrient balance in beef steers. Therefore, the effects of roughage concentration in dry-rolled corn (DRC)-based diets containing 25% WDGS were evaluated in 8 steers (BW = 362 ± 3.71 kg) using a replicated Latin square. Data were analyzed with the fixed effects of dietary treatment and period and random effects of square and steer within square were included in the model. Diets consisted of 25% WDGS and the balance being DRC and coarsely ground alfalfa hay (AH) replacing corn at 2% (AH-2), 6% (AH-6), 10% (AH-10), and 14% (AH-14) of dietary dry matter. As a proportion of GE intake, fecal energy loss increased linearly (P = 0.02), and DE decreased linearly (P = 0.02) as dietary level of AH increased. Methane energy loss, as a proportion of GE intake, increased linearly (P < 0.01) and ME decreased linearly (P < 0.01) as dietary concentration of AH increased. Heat production tended (P = 0.10) to decrease reaching a minimum of 10% AH and increased from 10 to 14% AH inclusion. Moreover, as a proportion of GE intake, retained energy (RE) decreased (P < 0.01) as AH level increased in the diet. Reasons for the decrease in RE are 1) the increase in fecal energy loss that is associated with decreased ruminal digestibility of NDF when AH replaced DRC and the shift in ruminal VFA produced, 2) the decreased energy available for animal retention when NDF increased linearly as AH increased in the diet, and 3) the methane and heat energy associated with digestion of the fibrous portion of the AH. Neutral detergent fiber and OM excretion also increased linearly (P < 0.01) with increasing AH in the diet. The increased NDF and OM excretion were likely caused by the difference in digestibility of AH and DRC.

Effects of roughage concentration in dry-rolled corn-based diets containing wet distillers grains with solubles on performance and carcass characteristics of finishing beef steers1

Distillers grains and distillers solubles are by-products of grain fermentation used to produce ethanol and contain greater concentrations of NDF and ADF, compared with other grains and concentrates they replace in feedlot diets. Typical finishing diets in the United States contain 8.3% and 9.0% roughage. Therefore, it is plausible that the dietary concentration of roughage can be altered when distillers grains are included in feedlot diets. The effects of roughage concentration in dry-rolled, corn-based diets containing wet distillers grains with solubles (WDGS) were evaluated in steers (n = 128; initial BW = 339 kg), using Calan gates. Each diet was based on dry-rolled corn and contained 25% WDGS with coarsely ground alfalfa hay (AH), replacing corn at 2% (AH-2), 6% (AH-6), 10% (AH-10), and 14% (AH-14) of DM. Feed offered was recorded daily, orts were measured weekly, and BW was measured on d 0, 1, 35, 70, 105, 140, 174, and 175. After commercial harvest and chilling, carcasses were evaluated on-line with a beef carcass grading camera to assess marbling and yield grade traits. The data were analyzed using the Mixed Procedure of SAS, in which contrast statements were used to separate linear and quadratic effects of AH inclusion. Decreasing concentrations of AH in the finishing diet resulted in a tendency for a quadratic response (P = 0.07) in final BW, where BW increased from 2 to 6% AH inclusion but then decreased from 6 to 14% inclusion. Similarly, ADG from d 0 to end responded quadratically (P < 0.01), in which ADG increased from 2 to 6% yet subsequently decreased from 6 to 14% AH inclusion. Dry matter intake from d 0 to end increased linearly (P = 0.02) as AH inclusion increased in the diet, whereas G:F increased from 2 to 6% AH inclusion and then decreased linearly (P < 0.01) from 6 to 14% AH inclusion. Concentration of AH in the finishing diet did not affect HCW, marbling score, or the proportion of cattle grading USDA choice (P ≥ 0.18). However, dressing percent and LM area did respond in a quadratic manner (P < 0.02), in which they decreased from 2 to 10% AH inclusion and increased from 10 to 14% AH in the diet. Yield grade and adjusted 12th rib fat responded quadratically (P < 0.01), in which both increased from 2 to 6% AH inclusion and decreased from 6 to 14% inclusion. Analysis of responses of G:F and ADG on AH predict the apex at 3% and 7% for G:F and ADG, respectively, when fed in diets containing 25% WDGS.

Wet corn gluten feed and alfalfa hay levels in dry-rolled corn finishing diets: Effects on finishing performance and feedlot nitrogen mass balance1

One-hundred ninety-two crossbred steers (initial BW = 351 +/- 11 kg) were used to determine the effects of removing alfalfa hay (AH) from dry-rolled corn-based diets containing wet corn gluten feed (WCGF) on animal performance and nutrient (N and OM) mass balance in open feedlot pens. Steers were stratified by weight and assigned randomly to 24 pens (2 x 3 factorial) and fed for 132 d from June to October 2002. Experimental diets contained either 0 or 35% WCGF and 0, 3.75, or 7.5% AH, and were formulated to be isonitrogenous. For efficiency of gain, an interaction occurred (P = 0.09) between AH and WCGF. Feed efficiencies of cattle fed 35% WCGF were improved 4.4% (P = 0.10) compared with efficiencies of cattle fed no WCGF at 0% AH; there was a marked improvement in ADG for cattle fed WCGF compared with no WCGF in diets with 0% AH. Within 35% WCGF diets, efficiency decreased as AH inclusion increased (P = 0.06). Efficiency was equal across AH levels when 0% WCGF was fed; however, ADG was decreased when AH was removed. Interactions between AH and WCGF were not detected for other performance or carcass criteria; therefore, main effects of AH and WCGF are discussed. Daily intake, ADG, and HCW increased linearly (P < 0.05) as dietary AH level increased. Feeding 35% WCGF also resulted in greater DMI (P < 0.01) and a tendency for greater ADG and HCW (P < or = 0.10) compared with steers fed no WCGF. Interactions between AH and WCGF were not observed for feedlot N mass balance. As level of AH increased across diets, N intake, N retention, and N excretion increased (P < 0.05). Steers fed 35% WCGF consumed and excreted more N (P < 0.01) than those fed no WCGF. More manure DM (P = 0.11), OM, and N (P < 0.01) were removed from pens housing steers fed 35% WCGF as well as greater OM and N recovery in finished compost. More N (kilogram/steer) was also lost to volatilization as a result of greater N excretion when WCGF was fed. Expressed as a percentage of N excretion, loss of N from pens housing steers fed 0 and 35% WCGF was not different, averaging nearly 80%. These data suggest that AH has less value when dry-rolled corn-based diets contain 35% WCGF and can be decreased from conventional levels. Furthermore, loss of N from open feedlot pens is high during the summer months, and feeding WCGF may not reduce N losses during these times of year.

Intake and digestibility of alkaline hydrogen peroxide-treated wheat straw-alfalfa hay combinations fed to sheep

A 5 × 5 Latin square experiment utilizing mature wethers (78 kg) was conducted to investigate the effects of feeding combinations of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) and alfalfa hay on intake and nutrient digestibility. Diets consisted of an 80:20 forage to concentrate ratio on a dry matter (DM) basis. Dietary designations were based on ratios of AHP-WS: alfalfa hay in the diet. Quadratic responses (P &lt; 0.05) were noted for both DM intake (DMI) as a percentage of body weight and organic matter intake (OMI) expressed as g d−1. Greater DMI and OMI were noted when wethers were fed diets containing combinations of AHP-WS and alfalfa (40:40 and 20:60) than when fed those containing AHP-WS or alfalfa as the sole forage (80:0 or 0:80). No effects of diet on digestibilities of dietary components were observed, with digestibility of DM and OM averaging 67 and 69%, respectively, across diets. Wethers consumed greater amounts of digestible OM when fed combinations of the two forages than when either was fed alone. Molar proportions of all ruminal volatile fatty acids (VFA) except acetate responded in a quadratic (P &lt; 0.05) manner due to diet. Molar proportion of propionate decreased while molar proportions of other VFA increased with increasing level of alfalfa. Ruminal liquid and particulate dilution rates were not affected by diet. Time spent ruminating by sheep was increased linearly (P &lt; 0.05) by inclusion of alfalfa hay in the diet. Favorable comparisons of AHP-WS to high quality alfalfa hay demonstrate the effectiveness of the AHP treatment process to enhance the nutritive value of WS. Key words: Intake, digestibility, treated wheat straw, alfalfa, sheep