Effects of Diets Combining Peanut Vine and Whole-Plant Corn Silage on Growth Performance, Meat Quality and Rumen Microbiota of Simmental Crossbred Cattle

Peanut vine is a typical peanut by-product and can be used as a quality roughage resource. Whole-plant corn silage is a commonly used roughage. However, few studies have investigated the effects of diets combining peanut vine and whole-plant corn silage on growth performance, antioxidant capacity, meat quality, rumen fermentation and microbiota of beef cattle. To investigate these effects, eighty Simmental crossbred cattle (body weight, 451.27 ± 10.38 kg) approximately 14 months old were randomly divided into four treatments for a 90-day feeding experiment. A one-way design method was used in this experiment. According to the roughage composition, the cattle were divided into a control treatment of 45% wheat straw and 55% whole-plant corn silage (WG), and three treatments of 25% peanut vine and 75% whole-plant corn silage (LPG), 45% peanut vine and 55% whole-plant corn silage (MPG), and 65% peanut vine and 35% whole-plant corn silage (HPG), and the concentrate was the same for all four treatment diets. The results showed that compared to the WG group, the MPG group experienced an increase in their average daily feed intake of 14%, an average daily gain of 32%, and an increase in SOD activity in the spleen of 33%; in the meat, dry matter content increased by 11%, crude protein by 9%, and ether extract content by 40%; in the rumen, the NH3-N content was reduced by 36%, the relative abundance of Firmicutes increased, and the relative abundance of Bacteroidetes decreased (p < 0.05). These results showed the composition of 45% peanut vine and 55% whole-plant corn silage in the roughage improved growth performance, antioxidant capacity, meat quality, rumen fermentation, and microbiota of beef cattle.

Effects of Roughage on the Lipid and Volatile-Organic-Compound Profiles of Donkey Milk

The lipid molecules and volatile organic compounds (VOCs) in milk are heavily influenced by diet. However, little is known about how roughage affects the lipid and VOC contents of donkey milk. Accordingly, in the present study, donkeys were fed corn straw (G1 group), wheat hulls (G2 group), or wheat straw (G3 group), and the lipid and VOC profiles of their milk were determined using LC-MS and GC-MS. Of the 1842 lipids identified in donkey milk, 153 were found to be differential, including glycerolipids, glycerophospholipids, and sphingolipids. The G1 group showed a greater variety and content of triacyclglycerol species than the G2 and G3 groups. Of 45 VOCs, 31 were identified as differential, including nitrogen compounds, esters, and alcohols. These VOCs were significantly increased in the G2 and G3 groups, with the greatest difference being between the G1 and G2 groups. Thus, our study demonstrates that dietary roughage changes the lipid and VOC profiles of donkey milk.

In Vitro Evaluation of Winged Bean (Psophocarpus tetragonolobus) Tubers as an Alternative Feed for Ruminants

The purpose of the current study is to determine the effects of the replacement of cassava chips with winged bean (Psophocarpus tetragonolobus) tubers (WBTs) on gas production parameters, in vitro degradability, and ruminal fermentation in ruminant diets. The study was performed using a 3 × 4 factorial arrangements and was designed using a completely random method. Factor A employed three various roughage sources that were frequently used by locals to feed ruminants: Oryza sativa L. (a1), Brachiaria ruziziensis (a2), and Pennisetum purpureum (a3). The levels of WBTs substitutions for cassava chips at 0%, 33%, 66%, and 100% in the diet were selected as factor B. The experiment's findings revealed that replacing the cassava chips in the diet with WBTs at levels of 66 and 100% enhanced the fermentation process by producing a high gas volume at 96 h when Ruzi grass (RZ) was used as the main source of roughage (p < 0.01). The interaction between the roughage source and WBTs showed that organic matter (OM) degradability improved markedly in the case of RZ grass in combination with WBTs at all levels. Both the total volatile fatty acids (TVFAs) at 8 h of incubation and the average value decreased when a complete substitution of casava chips with WBT (WBT 100%) was employed or when employing rice straw as the main source of roughage (p < 0.01). There was no interaction between WBTs and roughage source on the ammonia-nitrogen (NH₃-N) concentration (ml/dL) and rumen microbial count (p > 0.05). In summary, WBTs can be used effectively when combined with grass (Ruzi and Napier). The implementation of WBTs as a novel alternative feed may effectively replace cassava chips without affecting rumen function.

Effect of Dietary Corn Stalk Inclusion on the Performance of Non-Nutritive Oral Behaviors of Drylot-Housed Beef Steers

Dietary forage levels contribute to the performance of non-nutritive oral behaviors (NNOB) in cattle, yet the impact of varying forage levels on these behaviors is unknown. To evaluate the impact of dietary corn stalk inclusion (CSI) levels on NNOB, rumination time, and activity, pre-dominantly British-continental crossbred drylot-housed steers (n=27) were blocked by weight and randomly assigned to one of three dietary treatments (5%, 10%, or 15%) of CSI on a DM basis. Animals were fitted with a rumination collar upon arrival that measured rumination time and activity and video recorded. Cattle that spent more time bar licking had greater DMI, tended to have greater ADG and be more active. CSI in this study did influence NNOB performance; however, the impacts observed were not as expected. Cattle fed the 10% CSI performed the most bar licking and tongue rolling. This pilot investigation suggest that these CSI were insufficient to have a meaningful impact on NNOBs. Cattle spending more time bar licking and bar licked more frequently may be more orally motivated as reflected in their increased DMI and activity levels.

Effect of increasing corn silage inclusion in finishing diets cattle with or without tylosin on performance and liver abscesses

A pooled analysis was performed to evaluate whether corn silage fed at 15% or 45% of diet DM impacted liver abscesses prevalence at slaughter in five previous experiments. Cattle fed 15% corn silage had 7.8% abscessed livers compared to 4.1% for cattle fed 45% corn silage when all diets contained tylosin. While improved due to increased corn silage inclusion, the objective of the current finishing study was to determine the impact of silage inclusion in finishing diets with and without tylosin on performance and incidence of abscessed livers in beef cattle. A total of 640 (BW = 334 ± 25 kg) steers were used in a generalized randomized block design with a 2 × 2 factorial treatment design. Treatments included two concentrations of corn silage (15% and 45% of diet DM), with or without tylosin for liver abscesses. This study used 32 pens of cattle with 20 steers per pen and 8 pens per treatment. There was a tendency for an interaction for feed efficiency (G:F; P = 0.10) where cattle fed 15% corn silage had a 2% increase in G:F when tylosin was added to the diet, but no improvements in G:F were observed when tylosin was added to diets containing 45% silage. There was an interaction between silage and tylosin inclusion for abscessed livers (P = 0.05). Cattle fed 15% corn silage without tylosin had the greatest incidence of abscessed livers (34.5%) compared to other treatments (P = 0.05), and the incidence of abscessed livers was decreased to 19% if tylosin was fed with 15% corn silage. Feeding 45% silage was effective at lowering the incidence of abscessed livers (P = 0.05) which was 12.4%, regardless of whether tylosin was fed. Feeding corn silage at 45% of diet DM (77.5% concentrate) was as effective as feeding tylosin to cattle on a 92.5% concentrate diet. Feeding corn silage at greater inclusions decreased daily gain (P ≤ 0.01) but increased final body weight when fed to an equal fatness (cattle fed 45% CS were fed 28 d longer). Feeding corn silage at 45% was more economical compared to feeding 15% corn silage, especially as corn prices increase, provided shrink is well managed. Feeding elevated concentrations of corn silage may be an economically viable method to reduce incidence of liver abscesses without antibiotic use for smaller operations that can manage more corn silage in finishing diets.

Evaluation of similar dietary roughage equivalency fed to beef steers during the growing and finishing phase

The objective of this experiment was to determine the influence that similar dietary roughage equivalency offered in a single or two-diet system during a 210-d growing-finishing period has on growth performance, the efficiency of dietary net energy (NE) utilization, and carcass traits in beef steers. Beef steers (n = 46; initial shrunk [4%]; body weight [BW] = 281 ± 40.4 kg) were fed once daily, and bunks were managed according to a slick bunk management system across all 10 pens. Treatments included the following: 1) A single diet program that was formulated to provide 16% (dry matter [DM] basis) dietary roughage equivalency; SD) or 2) multiple diet programs (formulated to provide a dietary roughage equivalency (DM basis) of 25% for 98 d, 16% for 14 d, and 7% for 98 d; MD). Day 1 to 112 was considered the growing period, and day 113 to 210 (the day of harvest) was considered the finishing period, all steers were implanted on day 1 with a 100 mg trenbolone acetate (TBA) and 14 mg estradiol benzoate (EB) implant and implanted with a 200 mg TBA and 28 mg EB implant on day 112. Average daily gain tended (P = 0.06) to be 9.5% greater for SD compared to MD during the growing portion, and average daily gain (ADG) was greater by 11.3% (P = 0.01) for MD compared to SD during the finishing phase of the experiment. Cumulative ADG did not differ (P ≥ 0.86) between treatments (1.61 vs. 1.62 ± 0.046 kg) for SD and MD, respectively. Cumulative dietary NEm and NEg calculated based on performance did not differ (P ≥ 0.96) between treatments. There were no differences (P ≥ 0.18) detected between treatments for hot carcass weight, dressing percent, longissimus muscle area, rib fat, United States Department of Agriculture (USDA) marbling score, kidney, pelvic, heart fat, yield grade, retail yield, empty body fat, or body weight at 28% estimated empty body fat. These data indicate that feedlot producers can feed a single growing-finishing diet to beef steers with minimal effects on overall growth performance or carcass traits.

Effects of wood kraft pulp as a partial replacement for roughage on rumen fermentation and productivity in dairy cows

In this study, we evaluated the partial replacement of roughage with wood kraft pulp (KP) on rumen fermentation and productivity of dairy cows. Eighteen cows were divided into control and KP groups. The KP group started adaptation to KP 3 weeks before calving; after calving, they were fed a total mixed ration for 12 weeks, wherein 18% Timothy hay was replaced with KP. The dry matter intake, body weight, and milk yield and composition were similar in the control and KP groups. The average daily rumen pH was higher with KP feeding, and the average daily ruminal temperature remained lower at 16 days after calving (P < 0.05). The concentration of volatile fatty acids remained unaltered, the molar proportion of acetic acid decreased, and the molar proportion of propionic acid increased, indicating a low acetic acid:propionic acid ratio (P < 0.05). Lipopolysaccharide activity in the rumen fluid was higher in the KP group (P < 0.05); however, the rumen microbiota were unaffected. The digestibility of dry matter and neutral detergent fiber increased 12 weeks after calving, whereas excretion of urinary nitrogen decreased (P < 0.05). Partial replacement of roughage with KP did not suppress rumen fermentation and maintained postpartum productivity.

Spineless Cactus plus Urea and Tifton-85 Hay: Maximizing the Digestible Organic Matter Intake, Ruminal Fermentation and Nitrogen Utilization of Wethers in Semi-Arid Regions

The aim of this study was to evaluate the effect of replacing Tifton-85 hay (Cynodon spp. cv. Tifton 85) with 0, 150, 300, 450 and 600 g/kg dry matter (DM) of spineless cactus (SC, Nopalea cochenilifera Salm-Dyck) plus urea and ammonium sulfate (UAS; 9:1) on DM, digestible organic matter (DOM) and indigestible neutral detergent fiber (iNDF) intakes, as well as ruminal fermentation, N-balance, and microbial protein supply (MPS). Five rumen-fistulated and cannulated crossbred wethers, weighing 43.8 ± 5.80 kg, were randomized in a 5 × 5 Latin square design. Isonitrogenous diets (14% crude protein) were supplied with a roughage/concentrate ratio of 70:30. The DOM intake, N-retained, and MPS showed quadratic responses (p < 0.05), with maximum values estimated at the levels of SC+UAS of 414, 438 and 418 g/kg DM, respectively. Rumen pH and ammonia nitrogen, iNDF intake, N-urinary excretion, and serum urea and plasma ammonia reduced linearly (p < 0.05) with increasing SC+UAS inclusion. Ruminal acetate and propionate concentrations increased linearly with increasing SC+UAS inclusion. In wethers fed diets with a roughage/concentrate ratio of 70:30, roughage constituted of a SC+UAS/hay (Tifton-85) ratio of 41:29 is recommended in order to maximize the DOM intake, N-retention, and MPS.

Analysis of Housing Risk Factors for the Welfare of Lean and Heavy Pigs in a Sample of European Fattening Farms

Simple Summary

Animal welfare is a major challenge that most European pig producers have been facing in recent decades to comply with EU legislation and to meet the increasing societal and market demand for pork produced in a sustainable way. Pig welfare is ruled in terms of minimum requirements for housing and management, but stakeholders have considered that both farm-level and animal-based indicators are fundamental to monitor animal welfare. Some of the welfare issues still affecting fattening pigs are the lack of space, bedding and manipulable material, and the continued practice of routine tail docking of pigs. Tail docking is applied routinely across most European countries to reduce the occurrence of severe tail biting lesions, despite its ban in the EU. An observational study on 51 pig farms in seven EU countries, aimed at investigating housing risk factors for the welfare of finishing pigs, showed that body weight and presence of bedded solid floored resting area (BED) identify three clusters of farms. The outcomes of this study confirmed that BED and larger availability of space per pig, above the minimum requirement of EU legislation, can limit the occurrence of lesions in pigs with undocked tails.

Abstract

Pig welfare is affected by housing conditions, the minimum requirements of which are set up by EU legislation. Animal and non-animal-based measures are useful indicators to investigate housing risk factors for pig welfare. An observational study on 51 pig farms in seven EU countries, aimed at investigating housing risk factors for the welfare of finishing pigs, showed body weight and presence of bedded solid floored resting area (BED) identifying three clusters of farms. Farms with BED were featured by no or limited tail docking, larger availability of manipulable materials and lower number of pigs per farm and per annual work unit. In these farms, less skin and ear lesions were found, compared with lean pigs of farms without BED, which were characterized by lower pig space allowance, mortality rate and medication cost. In farms without BED, heavy pigs were featured by more space per pig, more pigs per drinker and higher mortality rate and medication cost per pig, compared to lean pigs. No statistical difference in tail lesions was found between the three farm clusters, although tail docking was performed in all farms without BED and not performed on most farms with BED.

Effects of grain adaptation programs and antimicrobial feed additives on performance and nutrient digestibility of Bos indicus cattle fed whole shelled corn

Two experiments were conducted to evaluate the effects of feed additives [monensin (MON); 30 mg/kg of dry matter (DM), and virginiamycin (VM); 25 mg/kg DM] and grain adaptation programs [adding roughage (ROU; sugarcane bagasse) or not (NO-ROU) during the 20-d adaptation period] on performance, carcass characteristics, and nutrient digestibility of Bos indicus cattle fed finishing diets containing 85% whole shelled corn and 15% of a pelleted protein-mineral-vitamin supplement. In Exp.1, 105 Nellore bulls [initial body weight (BW) = 368 ± 25 kg] were used in a complete randomized block design with a 2 × 2 factorial arrangement of treatments, consisting of two feed additives (MON and VM) associated with two adaptation programs (ROU or NO-ROU during the 20-d adaptation period). Effects of feed additives × adaptation programs were not detected (P ≥ 0.13). Feed additives did not affect dry matter intake (DMI), average daily gain (ADG), and feed efficiency (G:F) during the 20-d adaptation period (P ≥ 0.35). During the total feeding period (105 d), feeding MON decreased DMI (P ≤ 0.03) compared to VM. Adding sugarcane bagasse to finishing diets during the 20-d adaptation period (ROU) increased ADG (P = 0.05) and G:F (P = 0.03), and tended to increase BW (P = 0.09) compared to NO-ROU. In Exp. 2, 10 ruminally cannulated Nellore steers (BW = 268 ± 38 kg) were used in a completely randomized design to evaluate the effects of the two feed additives used in the Exp. 1 (MON and VM; 5 steers/treatment) on DMI, total apparent digestibility of nutrients, and ruminal fermentation characteristics. No differences in DMI, total tract apparent digestibility of nutrients, and ruminal fermentation characteristics were observed between MON and VM (P ≥ 0.32). An effect of sampling day (P < 0.001) was observed for ruminal pH, which was greater on day 0 compared to day 7, 14, and 21 of the experimental period (P ≤ 0.05). In summary, supplementing monensin and virginiamycin for finishing Nellore bulls fed whole shelled corn diets, resulted in similar growth performance and carcass characteristics. Including sugarcane bagasse to adapt finishing bulls to no-roughage diets containing whole shelled corn is an alternative to increase growth performance.

Basic Needs in Horses?-A Literature Review

Simple Summary

All animals have requirements that are essential for their welfare, and when these basic needs are not met, the animal suffers. In horses, it is claimed that these needs include social contact, social companionship, free movement and access to roughage in the form of grass, hay and/or straw. To validate this claim, this review examines 38 studies that reported on horses’ responses when one or more of these factors are restricted. We categorised the type of responses investigated: (a) Stress (e.g., increased stress hormones), (b) Active (e.g., increased aggression), (c) Passive (e.g., depressive-like behaviour) and (d) Abnormal Behaviour (e.g., stereotypies), and analysed the frequencies with which the investigated responses were shown. Overall, the studies reported that horses did react to restrictions in the described basic needs, especially to combinations of restricted social contact, free movement and access to roughage. The observation of passive responses and the development of abnormal behaviour provided compelling evidence that horses were suffering under these restrictions, and existing abnormal behaviours indicated that they had suffered at some time in the past. We conclude that the literature supports the claim that social contact, free movement and access to roughage are basic needs in horses and need to be taken into consideration to ensure their mental and physical welfare in management and training.

Abstract

Every animal species has particular environmental requirements that are essential for its welfare, and when these so-called “basic needs” are not fulfilled, the animals suffer. The basic needs of horses have been claimed to be social contact, social companionship, free movement and access to roughage. To assess whether horses suffer when one or more of the four proposed basic needs are restricted, we examined several studies (n = 38) that reported behavioural and physiological reactions to these restrictions. We assigned the studies according to the four types of responses investigated: (a) Stress, (b) Active, (c) Passive, and (d) Abnormal Behaviour. Furthermore, the number of studies indicating that horses reacted to the restrictions were compared with the number of studies reporting no reaction. The limited number of studies available on single management restrictions did not allow conclusions to be drawn on the effect of each restriction separately, especially in the case of social companionship. However, when combinations of social contact, free movement and access to roughage were restricted, many of the horses had developed responses consistent with suffering. Passive Responses, indicating acute suffering, and Abnormal Behaviour, indicating suffering currently or at some time in the past, were especially clearly demonstrated. This provides further evidence of the usefulness of assessing behavioural parameters in combination with physiological measurements when evaluating horse welfare. This meta-analysis of the literature confirms that it is justified to claim that social contact, free movement and access to roughage are basic needs in horses.

Aspergillus oryzae and Aspergillus niger Co-Cultivation Extract Affects In Vitro Degradation, Fermentation Characteristics, and Bacterial Composition in a Diet-Specific Manner

AOAN may provide enzymes to improve the digestibility of feeds and enhance rumen fermentation. This study determined the effects of AOAN on digestibility, fermentation characteristics, and bacterial composition using in vitro gas recording fermentation system. A total of 30 mg of AOAN was supplemented into 500 mg of TMR, corn silage, oat hay, and alfalfa hay. Fermentation parameters and bacterial communities were determined after 48 h fermentation, and digestibility was determined after 7, 24, 30, and 48 h fermentation. Gas production and dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility were significantly increased by AOAN supplementation at 48 h (p < 0.05), except for digestibility of CP of the TMR (p > 0.05). AOAN increased starch digestibility in corn silage (p < 0.05) and tended to increase that in TMR (0.05 < p < 0.10). AOAN supplementation increased total volatile fatty acid production (p < 0.05). The molar proportions of acetate and acetate to propionate ratio of oat hay and alfalfa hay were increased (p < 0.05). The 16S rRNA analysis revealed that the microbial richness of TMR and oat hay, and microbial evenness of TMR were increased (p < 0.05). AOAN did not affect the α diversity, β diversity, and bacterial composition of the corn silage. The relative abundance of Prevotella was increased and Ruminococcus was decreased in TMR, oat hay, and alfalfa hay. In conclusion, results suggest that AOAN has the potential to improve the utilization of diets differently, including providing enzymes with changing microbiota (TMR, oat hay, and alfalfa hay) or providing enzymes alone (corn silage).

Genetic parameters of forage dry matter intake and milk produced from forage in Swedish Red and Holstein dairy cows

High-yielding dairy cows are often fed high proportions of cereal grain and pulses. For several reasons, it would be desirable to replace these feed sources with forage, which is not suitable for human consumption. Feeding large amounts of forage to dairy cows could also make dairy production more publicly acceptable in the future. In this study, we estimated genetic parameters for total dry matter intake (DMI), DMI from forage (DMI_For), energy-corrected milk (ECM), and ECM produced from forage (ECM_For). A total of 1,177 lactations from 575 cows of Swedish Red (SR) and Holstein (HOL) dairy breeds were included in the study. Mixed linear animal random regression models were used, with fixed effect of calving season and lactation week nested within parity 1 and 2+, fixed effect of calving year, and random regression coefficients for breeding value (up to linear) and permanent environmental effect (up to quadratic) of the cow. Heritability for DMI and DMI_For was generally higher for HOL than for SR in all-parity data and in later parities; however, the opposite was true for first parity. Heritability for DMI and DMI_For during the first 8 wk averaged 0.11 and 0.15, respectively, in all-parity data for the 2 breeds. Corresponding values for ECM_For and ECM were 0.21 and 0.29, respectively. In first parity, values were 0.32, 0.36, 0.28, and 0.51, respectively. The genetic correlation between DMI and DMI_For was high, above 0.83, and fairly constant across the lactation. The genetic correlation between ECM_For and ECM was close to unity in the later part of lactation for both breeds, but was around 0.8 in the early lactation for both breeds; it decreased for HOL to 0.54 in wk 17. The genetic correlations between DMI and ECM_For and between DMI_For and ECM_For were low and negative for HOL (absolute value ∼0.2-0.3), but changed for SR from weakly positive in early lactation to negative values and back to positive toward the end of lactation. For most traits, the correlation between wk 1 and wk 8 into the lactation was very high; the lowest value was for DMI in HOL at 0.81. The genetic correlation between parities was rather high in the first part of the lactation. During the first 8 wk, the correlation was lower for HOL than for SR, except for ECM. We found that DMI_For and ECM_For showed reasonably large heritability, and future work should explore the possibility of genomic evaluations.

Effect of silage source, physically effective neutral detergent fiber, and undigested neutral detergent fiber concentrations on performance and carcass characteristics of finishing steers

This study was designed to evaluate the effect of silage source (barley vs. wheat silage) when harvested at two chop lengths (low vs. high physically effective neutral detergent fiber [peNDF]) and when barley silage was partially replaced with straw to increase the undigested neutral detergent fiber (uNDF) concentration on performance and carcass characteristics of finishing steers. Four hundred and fifty yearling commercial crossbred steers with an initial body weight (BW) of 432 ± 30.5 kg were allocated to 30 pens and fed diets containing 90% concentrate:10% forage for 123 d in a completely randomized block design with a 2 × 2 + 1 factorial arrangement. Treatments included 1) barley silage (BarS) with low peNDF (LpeNDF); 2) BarS with high peNDF (HpeNDF); 3) BarS with straw to yield a diet with LpeNDF + uNDF; 4) wheat silage (WhS) LpeNDF; and 5) WhS HpeNDF. There were no silage × peNDF interactions for dry matter intake (DMI), average daily gain (ADG), or gain to feed ratio (G:F), but cattle fed WhS LpeNDF had a lower (P < 0.01) proportion of yield grade 3 and a greater proportion in yield grade 2 carcasses than cattle fed BarS LpeNDF or HpeNDF and WhS HpeNDF. Cattle fed WhS LpeNDF had greater (P = 0.02) incidence of severe liver abscesses when compared with cattle fed BarS LpeNDF or HpeNDF and WhS HpeNDF. Cattle fed BarS consumed less (P < 0.01) uNDF as a percentage of BW, had increased (P = 0.02) ADG, heavier (P = 0.02) hot carcass weight, with greater (P = 0.01) back fat thickness, and (P < 0.01) incidence of minor liver abscesses when compared with cattle fed WhS. Feeding HpeNDF did not affect DMI, ADG, or G:F, but increased (P = 0.02) marbling score and reduced (P < 0.01) the proportion AA quality grade and increased (P < 0.01) those classified as AAA when compared with cattle fed LpeNDF. Cattle fed low uNDF had lesser (P < 0.01) uNDF intake as a percentage of BW, greater dressing percentage (P = 0.01), had a lower (P < 0.01) proportion of carcasses in yield grade 2, and a greater (P < 0.01) proportion of carcasses in yield grade 3 when compared with cattle fed high uNDF. Thus, silage source, peNDF, and uNDF content do not impact DMI or G:F when diets contain 10% forage, but BarS relative to WhS as well strategies increasing the peNDF concentration may increase ADG, HCW, back fat thickness, dressing percentage, marbling score, and carcasses classified as quality grade AAA. Future research is needed to evaluate the usefulness of peNDF and uNDF in rations for finishing cattle.

The Effects of Total Mixed Ration Feeding with High Roughage Content on Growth Performance, Carcass Characteristics, and Meat Quality of Hanwoo Steers

This study investigated the dietary effect of total mixed ration (TMR) based on high roughage content on the growth performance, carcass characteristics, and meat quality of Hanwoo steers. Twenty-four Hanwoo steers (average body weight, 195.3±4.7 kg; age, 8.5 mon) were randomly allocated to three experimental groups according to forage and concentrate ratio (DM basis): 25:75 (control), 50:50 (T₅₀), and 70:30 (T₇₀). Productivity in the fattening period and final body weight were significantly higher in the control. Average daily gain and feed conversion ratio were the same among treatments. Serum parameters, cholesterol, blood urea nitrogen, and total protein were higher in the control. Carcass weight was comparable in the control and T₅₀ but feeding more roughage was significantly correlated with a higher intramuscular fat. Shear strength and drip loss were higher while n-6/n-3 was lower in T₇₀ compared to the other groups. However, meat color was not significantly different among treatments. In terms of free amino acid contents, glutamic acid and glycine were higher in the control than T₅₀ and T₇₀. Overall, feeding Hanwoo steers with high forage content TMR had the lowest n-6/n-3 ratio of fatty acid content but highest intramuscular fat, shear strength, and drip loss. High forage content TMR is the best feed for Hanwoo steers that gives more benefits for human health and consumption but also provides the best meat grade and quality, which is important in the beef market in Korea.

Optimum roughage proportion in barley-based feedlot cattle diets: total tract nutrient digestibility, rumination, ruminal acidosis, short-chain fatty absorption, and gastrointestinal tract barrier function

Cattle need physically effective fiber to promote rumination and maintain rumen health, but economics favor the use of low-roughage feedlot diets. The study investigated the optimum barley silage proportion in barley-based finishing diets. Apparent total-tract digestibility (4-d total fecal collection), chewing behavior (6-d video recording), ruminal pH (6-d indwelling pH recording), and fermentation (1 day, sampling 0, 3, 6, 12, and 18 h postfeeding), short-chain fatty acid (SCFA) absorption (washed reticulo-rumen technique), gastrointestinal tract barrier function (marker infusion), and blood variables (catheters) were measured. Eight ruminally fistulated crossbred beef heifers (653 ± 44.2 kg; mean starting body weight [BW] ± SD) were used in a replicated 4 × 4 Latin square design with 28-d periods. Dietary treatments were 0%, 4%, 8%, and 12% of dietary dry matter (DM) as barley silage, with diets containing 80%, 76%, 72%, and 68% barley grain, respectively. Increasing silage proportion decreased dietary starch content from 49.0% to 43.1% DM, while neutral detergent content increased from 22.7% to 25.1% DM. Silage proportion had no effect on DM intake, but apparent DM digestibility decreased quadratically (86.0%, 82.1%, 81.1%, 79.5% for the four diets, respectively; P < 0.001). Although, silage proportion had no effect on eating activity, rumination time increased quadratically (246, 289, 302, 316 min/d; P = 0.04). Increased silage proportion increased minimum (5.07, 5.27, 5.29, 5.41; quadratic, P = 0.011) and mean (5.61, 5.87, 5.93, 5.95; quadratic, P = 0.007) ruminal pH, and there was a quadratic (P ≤ 0.047) decrease in duration and area under the pH acidosis threshold curves of 5.8, 5.5, and 5.2. Although increasing silage proportion decreased ruminal acidosis, it was not completely eliminated even with a diet containing 12% silage DM. SCFA concentration in ruminal fluid was not affected by diet, but silage proportion quadratically (P ≤ 0.088) increased ruminal acetate:propionate. There was no effect of diet on absolute or fractional rates of absorption of acetate, propionate, butyrate or total SCFA, and no effect on gastrointestinal barrier function or blood measurements. In conclusion, responses to roughage level were mostly quadratic with greatest improvements in acidosis variables between 0% and 4% barley silage, with incremental improvements with further increases in silage levels. The study showed a trade-off between maximizing digestibility and energy intake to promote animal performance and minimizing the risk of acidosis.

Effects of source and concentration of neutral detergent fiber from roughage in beef cattle diets on feed intake, ingestive behavior, and ruminal kinetics

The objectives of this research were to evaluate the effects of source and concentration of α-amylase-treated neutral detergent fiber (aNDF) from roughage on feed intake, ingestive behavior, and ruminal kinetics in beef cattle receiving high-concentrate diets. Six ruminally cannulated Nellore steers (408 ± 12 kg of body weight) were randomly assigned to a 6 × 6 Latin square design with six diets: 10% aNDF from corn silage (10CS); 20% aNDF from corn silage (20CS); or four diets containing 10% aNDF from corn silage and 10% aNDF from one of the following sources: sugarcane (SC), sugarcane bagasse (SCB), soybean hulls (SH), or low oil cottonseed hulls (LOCH). The parameters of passage and degradation kinetics were estimated based on a two-compartmental model with gamma- and exponential-distributed residence times. The nonlinear models were fitted by nonlinear least squares, and a linear mixed-effects model was fitted to all variables measured from the Latin square design that were related to intake, digestibility, digestion kinetic parameters, and residence times. Mean particle size (MPS) between roughage sources (CS, SCB, and SC) and coproducts (SH and LOCH) was affected (P < 0.05). Dry matter intake (DMI) was not affected (P > 0.05) by 20CS, SC, SH, or LOCH. Steers fed 20CS or LOCH diets had 16% and 20% greater DMI, respectively, (P < 0.05) than steers fed 10CS diet. Steers fed SCB consumed the least dry matter (DM). The SH and LOCH diets had lower MPS values (about 8.77 mm) in comparison to 20CS, SCB, and SC diets (about 13.08 mm) and, consequently, affected (P < 0.05) rumen content, ruminal in situ disappearance, nutrient digestibility, and solid fractional passage rate. Chewing time was affected (P < 0.05) by roughage sources and concentration. Lower values of distance travel inside the rumen (min/cm) were observed (P < 0.05) for the SCB and SC diets in comparison with any other diet. Except for SCB, there was no difference (P > 0.05) in rumen fill, among other treatments. Mean daily ruminal pH was not affected (P > 0.05) by 20CS, SCB, SC, and LOCH diets, and it ranged from 6.1 to 6.23. Total short-chain fatty acids concentration was affected (P < 0.05) by roughage source and concentration. Based on our results, we recommend that under Brazilian finishing diets, replacing roughage sources, except for SCB, based on aNDF concentration of the roughage in high-concentrate diets containing finely ground flint corn does not affect DMI.

The Effect of Feeding Roughages of Varying Digestibility Prepartum on Energy Status and Metabolic Profiles in Beef Cows around Parturition

Simple Summary

Grass silages based on timothy-meadow fescue are commonly fed to pregnant beef cows during winter. As beef cows usually are given free access to roughage for rational reasons, the use of these silages has been questioned due to their relatively high nutritional value, which may result in nutrient intakes above animal requirements and, hence, a waste of resources. Therefore, other roughage alternatives are requested, but their effects on cow intake and energy status before calving must be evaluated before applied in practice. Four diets based on timothy-meadow fescue silage, festulolium silage plus urea, reed canarygrass silage or barley straw supplemented with urea and rapeseed meal were fed in free access to mature pregnant beef cows. Timothy-meadow fescue and festulolium diets resulted in overfeeding of energy and protein and in body weight and body condition gains, whereas the opposite was observed for cows fed the other two diets. Hence, reed canarygrass or barley straw supplemented with urea and rapeseed meal prepartum may be suitable alternatives to the traditional timothy-meadow fescue diet, if cows are able to regain lost BCS during the grazing period, and may reduce winter feed costs of the cow-calf producer due to the low intakes of these diets.

Abstract

Resource efficient winter-feeding of mature pregnant beef cows requires knowledge of how different roughage-based feeding strategies affect cow intake and energy status. Four diets based on traditional timothy-meadow fescue silage (TM), festulolium silage plus urea (FE), reed canarygrass silage (RC) or barley straw supplemented with urea and rapeseed meal (BR), were fed ad libitum for 16 weeks prepartum to 36 Hereford cows. Postpartum, cows were fed the same diet before release on pasture. Individual data on cow intake, changes in body weight (BW), body condition score (BCS) and plasma metabolites, calf birth and weaning weights were recorded. The TM and FE diets resulted in increased BW and BCS prepartum (p < 0.001), while the RC and BR diets resulted in a catabolic state, as indicated by a loss of BCS, lower insulin levels and higher non-esterified fatty acid levels in cows fed BR (p < 0.001). There were no dietary effects on calf parameters (p > 0.29). Feeding RC or BR prepartum might be a possible alternative to traditional timothy-meadow fescue silage if cows are allowed to regain lost BCS during the grazing period. The influence on cow reproductive- and calf performance should be considered before making this management change.

Common Feeding Practices Pose A Risk to the Welfare of Horses When Kept on Non-Edible Bedding

During the evolution of the horse, an extended period of feed intake, spread over the entire 24-h period, determined the horses' behaviour and physiology. Horses will not interrupt their feed intake for more than 4 hours, if they have a choice. The aim of the present study was to investigate in what way restrictive feeding practices (non ad libitum) affect the horses' natural feed intake behaviour. We observed the feed intake behaviour of 104 horses on edible (n = 30) and non-edible bedding (n = 74) on ten different farms. We assessed the duration of the forced nocturnal feed intake interruption of horses housed on shavings when no additional roughage was available. Furthermore, we comparatively examined the feed intake behaviour of horses housed on edible versus non-edible bedding. The daily restrictive feeding of roughage (2 times a day: n = 8; 3 times a day: n = 2), as it is common in individual housing systems, resulted in a nocturnal feed intake interruption of more than 4 hours for the majority (74.32%, 55/74) of the horses on shavings (8:50 ± 1:25 h, median: 8:45 h, minimum: 6:45 h, maximum: 13:23 h). In comparison to horses on straw, horses on shavings paused their feed intake less frequently and at a later latency. Furthermore, they spent less time on consuming the evening meal than horses on straw. Our results of the comparison of the feed-intake behaviour of horses on edible and non-edible bedding show that the horses' ethological feeding needs are not satisfied on non-edible bedding. If the horses accelerate their feed intake (also defined as "rebound effect"), this might indicate that the horses` welfare is compromised. We conclude that in addition to the body condition score, the longest duration of feed intake interruption (usually in the night) is an important welfare indicator of horses that have limited access to roughage.

Pleurotus Ostreatus and Volvariella Volvacea Can Enhance the Quality of Purple Field Corn Stover and Modulate Ruminal Fermentation and Feed Utilization in Tropical Beef Cattle

This objective is to elucidate the effect of purple field corn stover treated with Pleurotus ostreatus and Volvarialla volvacea on feed utilization, ruminal ecology, and CH4 synthesis in tropical beef cattle. Four male Thai native beef cattle (100 ± 30 kg of body weight (BW) were assigned randomly as a 2 × 2 factorial arrangement in a 4 × 4 Latin square design. Factor A (roughage sources) was rice straw and purple field corn stover and factor B was species of white-rot fungi (P. ostreatus and V. volvacea). After fermentation, crude protein (CP) was increased in rice straw and purple field corn stover fermented with P. ostreatus and V. volvacea. The unfermented purple field corn stover contained 11.8% dry matter (DM) of monomeric anthocyanin (MAC), whereas the MAC concentration decreased when purple field corn stover was fermented with white rot fungi. There were no changes (p > 0.05) in DM intake of body weight (BW) kg/d and g/kg BW0.75 among the four treatments. The organic matter (OM), CP, and acid detergent fiber (ADF) intake were different between rice straw and purple field corn stover and were the greatest in the purple field corn stover group. Moreover, the current study showed that neutral detergent fiber (NDF) and ADF digestion was higher in purple field corn stover than in rice straw, but there were no significant differences between P. ostreatus and V. volvacea. There were significant effects of roughage sources on ammonia nitrogen (NH3-N) at 4 h after feeding. Bacterial population was changed by feeding with purple field corn stover fermented with P. ostreatus and V. volvacea. On the other hand, the number of protozoa was reduced by approximately 33% at 4 h after feeding with purple field corn stover (p < 0.01). Propionic acid concentration was different between roughage sources (p < 0.01) enhanced with purple field corn stover fermented with P. ostreatus and V. volvacea. In addition, methane production decreased by 15% with purple field corn stover fermented with P. ostreatus and V. volvacea compared to rice straw. There were significant differences on all nitrogen balances parameters (p < 0.05), except the fecal N excretion (p > 0.05) were not changed. Furthermore, microbial crude protein and efficiency of microbial N synthesis were enhanced when purple field corn stover fermented with P. ostreatus and V. volvacea was fed compared to rice straw group. Base on this study, it could be summarized that P. ostreatus or V. volvacea can enhance the quality of purple field corn stover and modulate rumen fermentation and feed digestion in Thai native beef cattle.

BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: Energy and roughage levels in cattle receiving diets and impacts on health, performance, and immune responses1

Transition of newly received feedlot cattle from a forage- to grain-based diet is challenging, and the appropriate roughage level in receiving diets is debatable. Nutritionists must consider the paradox of dietary transition and roughage level to mitigate ruminal acidosis, yet concomitantly low feed intake presents difficulty in achieving nutrient requirements when metabolic demand is increased due to inherent stress and disease challenge during the receiving period. Previous research suggests that performance is improved at the expense of increased morbidity for newly received cattle consuming diets with less roughage and greater starch concentration. The clinical signs of bovine respiratory disease (BRD) and acute acidosis are analogous; therefore, it is probable that acidotic cattle are incorrectly diagnosed with BRD in both research and production settings. Additional research efforts have attempted to elucidate alterations in microbial populations and digestion, physiological response to inflammatory challenge, and immunological response to infectious bovine rhinotracheitis virus challenge in cattle consuming diets of various roughage levels. Furthermore, our understanding of the rumen microbiome is improving rapidly with culture-independent assays, products such as direct-fed microbials are available, and increased availability and use of fibrous byproduct ingredients requires further attention. Beef cattle nutritionists and producers should consider that the health benefit of receiving diets containing greater levels of roughage and lower energy may not compensate for the reduction in performance compared with feeding receiving diets with lower roughage and greater energy.

Alkali addition and roughage inclusion effect on performance and carcass characteristics of feedlot steers fed diets containing 60% dried distillers grains with solubles

Three experiments were conducted to determine the effectiveness of calcium hydroxide (Ca(OH)₂) addition and roughage inclusion on digestibility, performance, and carcass characteristics of steers fed 60% dried distillers grains with solubles (DGS). Statistical analyses for studies were conducted using the MIXED procedures of SAS. In experiment 1, 48 steers (353.5 ± 7.55 kg) were allotted to individual pens and fed 1 of 3 diets (dry matter [DM] basis) containing 60% dried DGS, 20% corn silage, and 4% supplement with: 1) 14.5% corn and no Ca(OH)₂; 2) 14% corn and 2% Ca(OH)₂; and 3) 14.5% additional corn silage and no Ca(OH)₂. Steers fed Ca(OH)₂ consumed the least (P = 0.03) and steers fed added corn silage consumed the most and had the least gain:feed (P = 0.02). Gain and carcass quality were not affected by treatment (P ≥ 0.48). In experiment 2, 112 steers (375.3 ± 19.25 kg) were allotted to pens (four pens per treatment; seven steers per pen) arranged as a 2 × 2 factorial (roughage × Ca(OH)₂) and fed one of four diets (DM basis) containing 60% dried DGS, 17% corn silage, and 4% supplement with: 1) 17.5% corn silage and no Ca(OH)₂; 2) 17% corn silage and 2% Ca(OH)₂; 3) 17.25% corn stover and no Ca(OH)₂; and 4) 17% corn stover and 2% Ca(OH)₂. Added stover decreased average daily gain (ADG) compared to added corn silage (P = 0.04). Ca(OH)₂ increased ADG when steers were fed stover, but not when steers were fed only corn silage (P = 0.05; interaction). In experiment 3, six ruminally cannulated steers (initial body weight = 352 ± 14.8 kg) were randomly allotted to a 6 × 6 Latin square design to determine the effects of roughage inclusion (corn, corn silage, stover) and Ca(OH)₂ addition (0% or 2%) on ruminal characteristics. Feeding stover decreased total volatile fatty acid(s) (VFA) concentration and DM digestibility compared to corn silage or corn (P < 0.01), whereas Ca(OH)₂ resulted in greater total VFA concentrations and DM digestibility (P ≤ 0.02). Stover increased rate of DM degradation (K_d) and rate of particle outflow from the rumen (P ≤ 0.04) but decreased extent of DM digestion and mean retention time (P ≤ 0.02) compared to corn or silage. Ca(OH)₂ increased K_d (P < 0.01) and tended to increase (P = 0.06) liquid passage rate. In conclusion, added roughage did not improve performance of cattle fed 60% dried DGS. Ca(OH)₂ may decrease intake and maintain performance of cattle fed 60% dried DGS with corn silage as the roughage source and increases ADG when corn stover replaces a portion of the corn silage.

90 The effect of removing tylosin from finishing diets with increasing roughage concentration on growth performance, carcass characteristics, and prevalence of liver abscesses of finishing cattle

A trial utilizing 3,340 beef steers (initial BW = 387 ± 14.2 kg; DOF = 161 ± 7) was conducted to evaluate the effects of tylosin removal from finishing diets with increasing roughage concentration. A randomized complete block design with 8 pen replications (70 steers/pen) and 4 treatments were used. Dietary treatments were: 1) 7.1% corn stalks with tylosin (7.1TYL), 2) 7.1% corn stalks with no tylosin (7.1NT), 3) 13.1% corn stalks with no tylosin (13.1NT), or 4) 19.1% corn stalks with no tylosin (19.1NT). Corn stalks replaced steam flaked corn on a DM basis. Data were analyzed using the ANOVA procedure of Stata 15 with fixed effects of treatment and block and pen was the experimental unit. Categorical data (carcass grade distributions and liver scores) were analyzed using logistic regression (binreg; Stata 15). Single degree of freedom contrasts were used to compare 7.1TYL vs. 7.1NT; 7.1TYL vs. 13.1NT and 19.1NT; and the linear effect of increasing roughage without tylosin. Increased roughage resulted in a linear increase in DMI (P < 0.001). Increased roughage linearly reduced final BW, ADG, and resulted in poorer G:F (P ≤ 0.001). Final HCW was similar between 7.1TYL and 7.1NT (411 vs. 410 kg, respectively; P = 0.49); however, HCW linearly decreased as roughage increased (410, 408, or 401 kg, respectively; P < 0.001). Tylosin inclusion reduced liver abscess occurrence by 32.1% (13.03 vs. 19.18%, respectively; P = 0.001). Liver abscess occurrence decreased linearly with increased roughage (19.18, 11.88, or 14.40%, respectively; P = 0.009). Increased roughage did not improve liver abscess severity (P ≥ 0.13).These data indicate that replacing steam flaked corn with corn stalks in diets without tylosin may reduce liver abscess occurrence but not severity. However, decreased dietary energy led to increased DMI and lighter HCW in cattle fed to the same DOF.

Digestibility and performance of steers fed varying inclusions of corn silage and modified distillers grains with solubles to partially replace corn in finishing diets

Two finishing and 1 digestibility experiment evaluated the partial substitution of corn with corn silage and corn modified distillers grains with solubles (MDGS). Steers were used in Exp. 1 (n = 295; 467 ± 52 kg) and Exp. 2 (n = 225; BW = 348 ± 27 kg) in a 2 × 2 + 1 factorial arrangement of treatments with factors including corn silage (15 or 45%) and MDGS (20 or 40%) plus a control diet consisting of 5% cornstalks and 40% MDGS. In Exp. 1, there were tendencies for a corn silage × MDGS interaction for ADG, final BW, and G:F (P ≤ 0.08). In the overall F-test for G:F, there were no differences between the control treatment and 15:20, 15:40, or 45:40 (P ≥ 0.15), however, steers fed the control treatment had increased G:F compared to steers fed 45:20 treatment diets (P = 0.03). In Exp. 2, there were no corn silage × MDGS interactions (P ≥ 0.12). As corn silage increased in the diet, ADG, final BW, and G:F decreased (P ≤ 0.01). As MDGS increased from 20 to 40%, ADG and G:F tended to improve (P ≤ 0.07). In the overall F-test, the control was not different for G:F from 15:20, 45:20, or 45:40 (P ≥ 0.15), but had a 4.8% poorer G:F compared to 15:40 (P < 0.01). In Exp. 3, ruminally fistulated steers (n = 6) were used in a 5 × 6 Latin rectangle design and fed 15 or 45% corn silage with 20 or 40% MDGS as a 2 × 2 factorial. An additional diet consisting of 95% corn silage and 5% supplement was fed. There were no corn silage × MDGS interactions for nutrient intake, total tract digestibility, ruminal pH measurements, acetate: propionate ratio (A:P), or in-situ disappearance data (P ≥ 0.31) for the 2 × 2 factorial. As corn silage increased in the diet, DMI, NDF intake, ruminal pH, A:P, in-situ NDF disappearance of corn bran, and DM disappearance of corn increased (P ≤ 0.09) with decreases in DM and OM digestibility (P ≤ 0.03). As MDGS increased in the diet, there was an increase in NDF intake, total volatile fatty acid concentration, and NDF disappearance of corn bran (P ≤ 0.03) with no differences for any other tested variables (P ≥ 0.13). In general, increasing corn silage in place of corn in finishing diets containing MDGS results in a modest reduction in ADG and G:F with increases in ruminal pH.

Behavior of sheep fed babassu cake (Orbygnia speciosa) as a substitution for elephant grass silage

This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia - UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage-to-concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency.

Manipulation of ruminal fermentation and methane production by dietary saponins and tannins from mangosteen peel and soapberry fruit

Four fistulated Holstein Friesian heifers were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement. The main factors were two roughage-to-concentrate ratios (R:C, 70:30 and 30:70) and two supplementation levels of soapberry fruit-mangosteen peel (SM) pellets (0 and 4% tannins-saponins of total diets). Rice straw was used as a roughage source. The diet was fed ad libitum as a total mixed ration. SM pellets contained crude tannins and saponins at 12.1 and 15.7% of DM, respectively. It was found that at R:C 30:70 the DM intake and the digestibility of DM, CP and NDF were increased (p < 0.05), while SM pellet supplementation reduced the DM digestibility (p < 0.05). Ruminal pH was decreased at R:C 30:70. Total VFA and propionate was increased at high concentrate level and after SM pellet supplementation (p < 0.05); simultaneously, the acetate concentration and the acetate-to-propionate ratios were decreased (p < 0.05). Methane production was decreased at R:C 30:70 and additionally when SM pellets were supplemented (p < 0.05). This was in agreement with the percentage of methanogens in total ruminal DNA. Furthermore, the number of fungal zoospores were reduced at a higher concentrate proportion (R:C 30:70) and by SM-pellet supplementation (p < 0.05). Protozoal populations were diminished when SM pellets were supplemented (p < 0.05). In this study, it was shown that the roughage-to-concentrate ratio, as well as the supplementation of SM pellets containing condensed tannins and saponins, caused changes in ruminal microorganisms and their fermentation end-products.

Intake, digestibility, nitrogen efficiency, and animal performance of growing and finishing beef cattle fed warm-season legume (Stylosanthes capitata plus Stylosanthes macrocephala) silage replacing corn silage

It was hypothesized that Stylosanthes cv. Campo Grande (ES) silage could be used as the single source of dietary forage for beef cattle and that performance on ES would be similar to corn silage (CS) at a 50:50 forage:concentrate. The objectives of this study were to evaluate intake, total and partial digestibility of nutrients, ruminal pH, ruminal ammonia, and productive performance in growing beef cattle fed diets with varying proportions of ES silage replacing CS. Treatments consisted of diets with ratios of 0:100, 25:75, 50:50, 75:25, and 100:0% ES:CS. Two experiments were conducted simultaneously. In the first experiment, 10 crossbred Holstein-Zebu bulls with an average initial weight of 272 ± 86 kg were used. The bulls were rumen and abomasums fistulated. An experimental design of two 5 × 5 Latin squares (Exp. 1) was used. The second experiment used 40 Nellore bulls with an average BW of 386 ± 30 kg in a completely randomized design (Exp. 2). Results showed a linear increase in CP intake (P < 0.05) in response to increased dietary ES. An increase in the proportion of ES in the diet had a negative linear effect on TDN. Apparent ruminal digestibility of CP increased linearly, and apparent intestinal digestibility of nonfibrous carbohydrates increased with the addition of ES to the diet (P < 0.05). Intestinal digestibility of DM exhibited a quadratic response (P < 0.05). Nitrogen balance, excretion of urinary urea, and plasma urea nitrogen did not respond to the inclusion of ES in the diet (P > 0.05). There was also no effect (P > 0.05) of ES inclusion on animal performance. Ruminal pH was not affected by an increased proportion of ES in the diet (P > 0.05), but ruminal pH was affected (P < 0.05) by the time of collection, for which a cubic model fit the data. There was an interaction (P < 0.05) between treatment and collection time for ruminal ammonia nitrogen concentration. It can be concluded that ES silage can be used as a source of roughage in the diet of beef cattle during the growing and finishing phases at a proportion of 50% of DM in the total diet. Therefore, ES silage is a promising alternative dietary ingredient and the use of this alternative source of silage will depend on availability and economic factors.

Increasing dietary neutral detergent fiber concentration decreases ruminal hydrogen sulfide concentrations in steers fed high-sulfur diets based on ethanol coproducts

Cattle feedlot diets commonly contain ethanol coproducts that are high in S. This dietary S is reduced in the rumen by sulfate reducing bacteria, resulting in an accumulation of hydrogen sulfide (H2S), increasing the risk for S toxicity. A negative correlation between H2S and ruminal pH has been observed previously. The objective of this study was to determine the effect of varying dietary NDF from chopped bromegrass hay (66% NDF) on performance, ruminal pH, and ruminal H2S gas concentration of steers fed a high-S finishing diet. One hundred fifty crossbred steers (359 ± 51 kg BW) were blocked by BW into pens of 5 steers and randomly assigned within block to 1 of 5 treatments (n = 6 pens per treatment) and fed for 84 d. Dietary treatments included 3.5, 5.7, 7.9, 10.1, or 11.4% roughage NDF (rNDF) from bromegrass hay and contained 0.46% dietary S from a combination of dried distillers grains with solubles and condensed corn distillers solubles. In all diets, hay was added at the expense of dry-rolled corn. Effective NDF increased linearly (P < 0.01) with increased inclusion of rNDF. Final BW was not affected by rNDF (P ≥ 0.12). The addition of roughage did not affect ADG (P ≥ 0.13) or gain efficiency (P ≥ 0.12). Dry matter intake increased linearly (P < 0.01) as rNDF concentration increased. There was a treatment × month interaction for S intake (P < 0.01), explained by steers fed 3.5 or 11.4% rNDF increasing S intake each month whereas the middle rNDF inclusions had similar S intake between months 1 and 2 and increased in month 3. Ruminal H2S concentrations and ruminal fluid pH were measured at 6 h postfeeding on d 7, 14, 21, 29, and 84. Ruminal pH increased linearly (P < 0.01; 5.48, 5.61, 5.71, 5.74, and 5.80 ± 0.041 for 3.5, 5.7, 7.9, 10.1, and 11.4% rNDF, respectively) and ruminal H2S concentrations decreased linearly (P < 0.01; 1.00, 0.86, 0.76, 0.70, and 0.62 ± 0.037 g/m(3) for 3.5, 5.7, 7.9, 10.1, and 11.4% rNDF, respectively) as rNDF inclusion increased. Using mixed model regression analysis, ruminal pH had a strong negative relationship with ruminal H2S concentrations (β = -0.63; P < 0.01). Under conditions of this study, increasing roughage did not affect cattle gains but helped maintain greater ruminal pH and decreased H2S concentration, suggesting that this dietary strategy may lessen the risk of S toxicity in feedlot cattle.

Effects of supplementary urea-minerals lick block on the kinetics of fibre digestion, nutrient digestibility and nitrogen utilization of low quality roughages

Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block (ULB) on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen (N) utilization of rice straw (RS), ammonia bicarbonate (AB)treated RS (ABRS) and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% (P<0.05) when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion (PED) and digestion rate of PED (kd) of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED (P<0.05) and kd (P<0.05) of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.