Hay Intake Research Articles

Effect of protein source and nonroughage NDF content in finishing diets of feedlot cattle fed free-choice hay on growth performance and carcass characteristics.

One-hundred twenty crossbreed steers (initial body weight (BW) 566 ± 42 kg) were used to evaluate the interaction of protein source (PS) and nonroughage NDF content (NRFC) in finishing diets of feedlot cattle fed free-choice hay on performance and carcass characteristics. Steers were stratified by BW and randomly assigned to 8 pens (2 × 2 factorial) and fed for 104 ± 10 d. Four dietary treatments were investigated: (1) distillers’ dry grains with solubles (DDGS) and a low NRFC (DLF), (2) DDGS and a high NRFC (DHF), (3) soybean meal (SBM) and a low NRFC (SLF), (4) SBM and a high NRFC (SHF). Free-choice grass hay and concentrates were offered in a different bunk. Data were analyzed as a randomized complete block design. Do to the confounded effect of PS and protein intake, a linear regression was used to evaluate the effect of protein intake in growth performance. For gain to feed ratio (G:F) an interaction tended to occur (P = 0.10) between PS and NRFC. Steers on the DHF treatment had a lower G:F compared with SLF and SHF. Feeding SBM increased (P = 0.05) final BW, tended to increase (P = 0.06) average daily gain (ADG), and decreased (P = 0.05) hay intake (HI) compared with steers fed DDGS. There was a positive association (P ˂ 0.01) of crude protein intake with ADG and FBW. Dietary NRFC did not change (P ≥ 0.3) final BW, ADG, DMI, and HI. Protein source did not affect (P ≥ 0.16) hot carcass weight (HCW), longissimus muscle (LM) area, dressing, 12th rib fat thickness, or marbling score (MS). No differences were detected between NRFC for dressing, HCW, LM area, or MS (P ≥ 0.18); but diets with greater NRFC decreased (P = 0.03) the 12th rib fat thickness. Steers in the SHF treatment presented the lesser kidney-pelvic-heart fat compared with the remaining treatments (PS × NRFC interaction, P = 0.04). Soybean meal inclusion/increase in protein intake improved growth performance of feedlot steers compared with DDGS, despite protein intake meet the protein requirement. Increasing the NRFC did not affect growth or HI but decreased feed efficiency of steers fed DDGS.

Tributyrin supplementation in pasteurized waste milk: Effects on growth performance, health, and blood parameters of dairy calves

This study evaluated the effects of incremental tributyrin supplementation in pasteurized waste milk on growth performance, health, and blood metabolism of dairy calves before and after weaning. Forty-eight newborn female Holstein dairy calves (39.6 ± 2.75 kg; mean ± standard deviation) were blocked by age and randomly assigned to 3 treatments: pasteurized waste milk (1) without supplementation, (2) with 1 g/L of tributyrin products (unprotected solid powder; containing 35% tributyrin), or (3) with 2 g/L of tributyrin products. The calves were weaned on d 56 and were raised until d 77. Data were analyzed for the preweaning, postweaning, and overall periods. The results showed that starter intake and hay intake were not different among treatments in any period of the trial, but the crude protein intake tended to increase linearly with tributyrin supplementation during the overall period. Although tributyrin supplementation had no effects on body weight during preweaning and overall periods, body weight increased linearly with tributyrin supplementation postweaning. The average daily gain tended to increase linearly during postweaning and overall periods. No effects were observed on feed efficiency in any period. A positive linear relationship between body length and tributyrin supplementation was observed during the postweaning period, but no differences were found for the other body structural measurements in any period. The results of diarrhea showed that tributyrin concentration had a negative linear relationship with diarrhea frequency during preweaning and overall periods. The rectal temperature did not differ among treatments in any period, but a treatment × week effect for rectal body temperature was observed. For blood metabolism, tributyrin supplementation had no effects on insulin, growth hormone, total protein, albumin, or globulin. No differences were found in serum amyloid A concentration in any of the periods, yet haptoglobin concentration decreased linearly with increasing tributyrin concentration during postweaning and overall periods. Endothelin concentration showed a tendency to decrease linearly during preweaning and postweaning periods and decreased linearly with tributyrin supplementation during the overall period. An increasing tributyrin concentration was associated with a negative linear relationship with IL-1β concentration during the preweaning period, and no differences were found in the other periods. The concentration of IL-6 and tumor necrosis factor α were not different among treatments in any of the periods. These data suggest that increasing the concentration of tributyrin in pasteurized waste milk could increase growth performance and health of dairy calves, and incremental tributyrin supplementation could linearly reduce haptoglobin, endothelin, and IL-1β concentrations, indicating a positive effect of tributyrin on alleviating oxidative stress and inflammatory status of dairy calves. Calves fed pasteurized waste milk supplemented with tributyrin products (containing 35% tributyrin) at 2 g/L compared with 1 g/L of milk had more improved growth and health.

Feed Intake Parameters of Horses Fed Soaked or Steamed Hay and Hygienic Quality of Hay Stored following Treatment.

Simple SummaryDusty hay is particularly harmful to horses with equine asthma, where the dust mainly consists of microbial deposits in addition to abiotic ones. Soaking and steaming hay can improve its hygienic quality by rinsing off dust, but also reducing the viability of microorganisms. In this study, we investigated whether the treated hay remains stable during subsequent storage, and how the horses’ feed intake as well as chewing activity change with treated hay. Microbial counts were determined by culture methods in meadow hay before and after soaking or steaming, and subsequent storage at 10 and 25 °C for 6, 12 and 24 h. Chewing activity was monitored while horses consumed native or treated hay. Steaming effectively reduced yeasts and typical mold. Steamed hay was almost stable during storage, but storing soaked hay increased yeasts, and typical bacteria and mold. The intake of soaked hay was characterized by a particularly low consumption rate and high chewing intensity, but these per se positive effects seemed to be biased by a lower acceptance. However, steaming can be used to reduce counts of viable microorganisms. The feeding of soaked hay is recommended directly after treatment, to avoid hygienic problems.Horses suffering from equine asthma must consume low-dust forage, with soaking and steaming being suitable methods of hay treatment. The impacts of this treated hay’s subsequent storage and effects on the horses’ chewing activity are largely unknown. Meadow hay was soaked (10–15 °C, 15 min) or steamed (100 °C, 60 min). Microbial counts (colony forming units (CFU)) were determined by culture before and after soaking or steaming, and subsequent storage at 10 and 25 °C for 6, 12 and 24 h (three replicates each). Six horses were fed native, soaked and steamed hay, according to a cross-over design, and chewing parameters were measured. Steaming reduced (p < 0.05) typical mold vs. soaking (0 vs. 50 CFU/g) and yeasts vs. native and steamed hay (0 vs. 102 and 90 CFU/g). Storing soaked hay elevated bacteria, mold, and yeasts (p < 0.05). Within the first 60 min of hay intake, the steamed hay and soaked hay were eaten slower (19.5 and 21.5 g dry matter/min, respectively; p < 0.05) and the steamed hay was chewed more intensely (steamed hay: 3537; native: 2622; and soaked: 2521 chewing cycles/kg dry matter, p < 0.05). Steaming particularly improves the hygienic quality of hay. Soaked hay is not stable when stored and is less accepted by horses.

Effects of bale feeder design on hay waste, intake, and apparent diet digestibility in gestating beef cows.

Two experiments were conducted to determine the effects of feeder design on hay intake, apparent diet digestibility, and hay waste in gestating beef cows. Native tallgrass prairie hay and a protein supplement was fed throughout both experiments. In Exp. 1, 56 crossbred cows were used in a Latin square arrangement. Feeder design treatments included a conventional open bottom steel ring (OBSR), an open bottom polyethylene pipe ring (POLY); a sheeted bottom steel ring (RING), and a sheeted bottom steel ring with a basket (BASK). Cows were weighed and allotted based on BW to one of four previously grazed 2.0 ha paddocks equipped with a concrete feeding pad. Fourteen cows were assigned to each paddock and three round bales were fed consecutively within each treatment period. The cows acclimated to the feeders while the first bale was being consumed. Subsequently, hay waste data were collected while the second and third bale within each period were being consumed. Waste was measured for each bale at 24, 48, 72, and 96 h after each bale was introduced into the pen. Hay waste was significantly affected by hay feeder design with 19.7, 21.1, 12.4, and 5.5% of original bale weight wasted for OBSR, POLY, RING, and BASK, respectively (P < 0.01). There was a feeder design × day interaction (P < 0.01) with greater waste when the bale was first introduced into the pen in OBSR, POLY, and RING feeders and gradually declining thereafter, while waste from the BASK feeder was consistently low. There was a tendency (P = 0.06) for cows eating from OBSR feeders to consume less hay than cows eating from RING feeders. Feeder design did not influence apparent diet digestibility (P = 0.46). In Exp. 2, 64 crossbred cows (body weight = 590 ± 59 kg) were used to determine waste, forage intake, and apparent diet digestibility when hay was fed from a sheeted bottom steel ring (RING) or a RING feeder with a cone insert (CONE). More hay was wasted when cows were fed from RING feeders compared to CONE feeders (11.9% vs. 4.8%, P < 0.01). Feeder design had no effect on DMI or apparent digestibility (P > 0.45). Hay savings from adopting a more conservative feeder design can have a dramatic influence on hay utilization by beef cows and thus on cost of production.

Effect of sugar and starch supplementation on feed intake and nutrient digestibility in addax (Addax nasomaculatus) and Reeves's muntjac (Muntiacus reevesi).

Two studies were conducted to determine the effect of the supplementation of sugar, starch or both on feed, nutrient and energy intake and total tract digestibility in four adult female addax (Addax nasomaculatus) and four adult male Reeves's muntjac (Muntiacus reevesi) - representatives of grazing and browsing ruminants, respectively. Studies in both species were conducted according to 4×4 Latin Square Design. Animals had free access to meadow hay (addax) or dehydrated chopped lucerne (muntjac), and were fed a restricted amount of a 'basal diet' consisting of: (1) wheat bran; (2) wheat bran and sucrose (source of sugar); (3) wheat bran and wheat (source of starch); or (4) wheat bran, sucrose and wheat. The amounts of supplemental sucrose and wheat were set to account for 2% and 15%, respectively, of dry matter (DM) consumed. There was no effect of the ~2% sugar supplementation on DM intake of hay by addax, while the ~10% starch supplementation reduced DM intake of hay by 13% (p<0.01); total DM intake (of hay and the basal diet) was not affected neither by sugar nor starch supplementation. When the diet for addax included wheat, this resulted in a greater intake of crude protein by 15%, lower intake of ADF by 9%, and greater crude protein digestibility by 10% (p≤0.05). The ~2% sugar supplementation did not affect intake of lucerne and total DM intake by muntjac, but the ~10% starch supplementation decreased DM intake of lucerne by 25% (p<0.01), total DM intake by 7% (p=0.02) and intake of all nutrients (p≤0.10). In summary, if high intake of roughages by captive ruminants is fundamental for their gastrointestinal functions and health, then starchy feeds supplementation should be limited, as they have an especially negative impact on roughage intake.

Relationship Between Gas Emissions and Dry Matter Intake in Mature Angus Cows

Abstract The objective of this study was to examine the effects of diet quality on greenhouse gas emissions and dry matter intake (DMI). We used 42 mature, gestating Angus cows (600±69 kg; and BSC 5.3±1.1) with a wide range in DMI EPD (-1.36 to 2.29). Cows were randomly assigned to 2 diet sequences forage-concentrate (FC) or concentrate-forage(CF) determined by the diet they consumed in each period (forage or concentrate). The cows were adapted to the diet and the SmartFeed individual intake units for 14 d followed by 45 d of intake data collection for each period. Body weight was recorded on consecutive weigh days at the beginning and end of each period and then once every two wk for the duration of a period. Cows were exposed to the GreenFeed Emission Monitoring (GEM) system for no less than 9 d during each period. The GEM system was used to measure emissions of carbon dioxide (CO2) and methane (CH4). Only cows with a minimum of 20 total &amp;gt;3-m visits to the GEM were included in the data set. Data were analyzed in a crossover design using GLIMMIX in SASv.9.4. Within the CF sequence there was a significant, positive correlation between TMR DMI and CH4 (r=0.81) and TMR DMI and CO2 (r=0.69), however, gas emissions during the second period on the hay diet were not correlated with hay intake. There was a significant, positive correlation between hay DMI and CO2 (r=0.76) and hay DMI and CH4 (r=0.74) when cows first consumed forage (FC). In comparison to the CF sequence, cows on the FC sequence showed a positive correlation between CO2 and TMR DMI during the second period. There was also a significant positive correlation between hay and TMR DMI when assessed across (r=0.43) or within sequence (FC r=0.41, CF r=0.47).

PSIV-3 Effect of Protein Source and Soy Hulls Inclusion in Finishing Diets of Feedlot Cattle Fed Free-choice Hay, on Performance and Carcass Characteristics

Abstract To evaluate the effect of soy-hulls (SH) inclusion in a ground corn-based diet with either distillers dry grains with solubles (DDGS) or soybean meal (SBM) as the protein source (PS), on growth and carcass characteristics of feedlot cattle offered free-access hay; one-hundred and nineteen crossbreed steers (initial BW 566 ± 42kg) were blocked by weight, randomly assigned to 8 pens, and fed for 104 ± 10d. Four dietary treatments were evaluated: 1) DDGS without SH inclusion, 2) DDGS and high inclusion of SH, 3) SBM and low inclusion of SH, and 4) SBM and high inclusion of SH. Diets were formulated to be isonitrogenous. Grass-hay was offered ad-libitum and separate from the concentrates in a different bunk (GrowSafe system). Data was analyzed as a 2×2 factorial considering the fixed effects of treatments and their interaction, and the random effects of block and steer within block. For gain to feed and kidney-pelvic-heart fat (KPH), an interaction occurred (P ≤ 0.10) between PS and SH inclusion (Table 1 and 2, respectively). With greater inclusion of SH, feed efficiencies of steers fed SBM improved compared with feed efficiencies of steers fed DDGS. Steers fed SBM and high SH had the lower KPH content. Feeding SBM increased (P = 0.05) final body weight, tended to increase (P = 0.06) the average daily gain, and decreased (P = 0.05) hay intake compared with steers fed DDGS (Table 1). No differences were observed (P ≥ 0.14) in carcass characteristics between PS and SH inclusion, except for backfat thickness which increased (P = 0.03) with lower SH inclusions (Table 2). These data suggest that opting for SBM as an alternative of DDGS as the protein source of ground corn-based diets, could conceivably enhance the finishing performance of feedlot steers regardless of the SH inclusion levels, and improve feed efficiency with greater levels of dietary SH.

83 Acceptability of red clover hay and associated eating behaviors of horses when compared to timothy hay

Forage preference and eating behaviors are influenced by prior exposure to a forage species and forage maturity. Therefore, introducing new forages to horses can be challenging. This study aimed to compare horse behavior and acceptance of hay, when given a choice between timothy hay (TH) and red clover hay (RCH); a subobjective of a study also evaluating in vitro fermentation. Twelve Thoroughbred horses were blocked by weight and sex and randomly assigned to TH (n = 8) or TH + 20% RCH (n = 4) diet, the unbalanced design due to a dietary treatment not reported here. The study included 2 periods of 4 weeks (n = 6/period) to accommodate the 12 horses. Horses were housed and fed in partially covered individual runs (3 × 12m) and turned out daily in paddocks with muzzles (9:00–15:00) that allowed water consumption. Horses participated in 3 preference tests (PF): one in wk 2 and 2 in wk 4. Horses were on pasture before the study, and transitioned to hay only diets during wk 1. Each successive PF served to test acceptability with continued exposure. On PF days horses were brought inside from turnout, but instead of receiving a full allotment of hay, were provided with a pre-weighed amount of hay in bins and observed for 1 h. Orts was weighed back. Horses (n = 8) allocated to TH diet received TH in both bins, serving as controls. Horses (n = 4) allocated to TH + RCH treatment received TH in one bin, and RCH in the other. Each PF occurred over 2 consecutive days, where hays were switched between bins and results averaged between days. Behavior assessment included the first bin approached, sniffed and consumed from, drinking water, switching bins, or no eating. Data were analyzed as repeated measures ANOVA (SAS 9.4). Bin placement had no effect ( P > 0.05). The PF total hay intake did not differ between TRT or time ( P > 0.05). Consumption of RCH decreased from PF 1 to 2 ( P < 0.01) and then remained the same ( P = 0.71). Horses consumed 47%, 26%, and 20% of total intake as RCH during each PF respectively, therefore replacing RCH with TH over time. Horses first approached and sniffed RCH 86% and 79% of the time, but only consumed RCH first 50% of the time. Horses on average drank twice, the first drink within 27 min of PF. Horses stopped eating (>1 min) on average 3 times. Behavior observations indicated a willingness to eat both hays, but TH was preferred over the long-term, whether due to differences in maturity or other sensory factors. Average voluntary RCH intake was 30.7%. In practice RCH will likely be fed at 15–20% of total intake. Thus, willingness to consume RCH at these reported levels is a valuable outcome for practical application.

Determination of maintenance energy requirement and responses of dry ewes to dietary inclusion of lucerne versus concentrate meal

An accurate value for metabolizable energy (ME) requirement for maintenance (MEm) is essential to enable sheep husbandry practice to reach its potential. The objectives of the study were to use calorimetry chamber data of dry ewes (Hu × thin-tail Han F1 crossbred) to develop updated MEm, examine effects of substituting concentrate feed with lucerne hay on energy partitioning, and explore the relationships between energy utilization and fasting heat production (FHP). Data were collected from three experiments. In Exps. 1, 2a and 2b, lucerne hay was used to replace concentrates in three levels (0:40%, 15:25% and 30:10%), with diets containing 60% maize stover (Exp. 1), fresh rye forage (Exp. 2a) or dry rye forage (Exp. 2b). Within each experiment, diets were isoenergetic (digestible energy, DE) and isonitrogenous. Exp. 3 aimed at evaluating effects of three BW levels on nutrient utilization of dry ewes offered diets containing 60% maize stover, 15% lucerne hay and 25% concentrates. Energy metabolism data were measured using the respiration calorimeter chamber technique in all three experiments, followed by the measurement of FHP in Exps. 1, 2b and 3. The MEm derived from the linear regression between energy balance (EB) and ME intake was 0.440 MJ/kg BW0.75. The average FHP was 0.326 MJ/kg BW0.75. The fasting metabolism, net energy requirement for maintenance (NEm) and MEm were estimated to be 0.336, 0.359 and 0.511 MJ/kg BW0.75, respectively, through adjustment of FHP using fasting urinary energy output, activity allowance and efficiency of ME use for maintenance. The FHP was negatively correlated to EB/metabolic BW, ME/gross energy (GE), ME/DE, EB/GE intake and EB/ME intake, while positively correlated to HP/GE intake, HP/ME intake and CH4-E/GE intake. Compared to zero lucerne hay diet, the 15% lucerne hay intake decreased HP (MJ/d), and had no negative effects on EB (MJ/d) or energy utilization efficiencies. The results indicate that nutrient requirement standards currently used across the world are likely to underestimate MEm for dry ewes, and the selection of low FHP ewes for breeding has the potential to improve sheep production efficiency.

Effects of crude protein content on intake and digestion of coastal bermudagrass hay by horses.

This study was conducted to determine the effects of forage crude protein (CP) level on intake and digestion of Coastal bermudagrass hay by horses. Four cecally fistulated geldings were used in a 4 × 4 Latin square design with four treatments and four periods. Horses were fed one of four Coastal bermudagrass hays consisting of 7%, 10%, 13%, or 16% CP during each of the four 15-d periods. Intake and apparent digestibility were determined for each horse at the end of each period by total fecal collection. In addition, cecal fluid and blood samples were collected on the last day of each period for the determination of cecal ammonia, cecal pH, plasma urea nitrogen (PUN), and plasma glucose concentrations. Data were analyzed using PROC MIXED of SAS. CP concentration of Coastal bermudagrass hay influenced equine intake and digestion. Increasing CP concentration linearly increased digestible organic matter intake (DOMI) from 3.79 to 5.98 kg/d for 7% and 16% CP hay, respectively (P = 0.04). Furthermore, as the forage CP level increased, CP intake increased linearly (P < 0.01). The forage CP level had no effect on forage dry matter intake. Quadratic effects (P ≤ 0.05) were observed for forage OM, neutral detergent fiber, acid detergent fiber, and digestible energy. Overall digestibility was lowest for the 7% CP hay and highest for the 10% CP hay. Cecal pH remained above 6.62 irrespective of treatment and time, indicating that cecal pH was suitable for microbial growth. As the forage CP level increased, cecal ammonia concentration increased linearly from 0.03 mM for the 7% to 1.74 mM for the 16% CP hay (P < 0.01). Concentration of plasma glucose also linearly increased (P = 0.04) from 68.77 to 73.68 mg/dL as CP concentration increased from 7% to 16% CP. PUN exhibited a quadratic effect as concentration increased (P < 0.01) from 4.34 to 5.61 mM for the 7% and 16% CP hays, respectively. Overall, the 10% CP hay had the highest digestibility due to its higher OM digestion. As forage OMI increased, digestible OM increased until physiological capacity for digestion is exceeded. At that point, digestion will decline with the decrease in OMI, explaining the lower digestion for other forages fed.

The use of an impeller mowing conditioner during haymaking had no effects on feeding behavior, feed intake or performance of organic dairy cows

AbstractImpeller mowing conditioners are commonly used to speed up the drying process on the field, making forage preservation (haying, ensiling) less dependent on weather conditions. However, the effects of this technique on the nutritive value of the forage and dairy cows' responses have not been investigated yet. Each half of two fields of grass-dominated swards, first regrowth, was cut either with or without the use of an impeller mowing conditioner (experimental hay and control hay, respectively).Ceteris paribusconditions were guaranteed by the same cutting and wilting times (roughly 48 h), number of teddings, field pickup technique and barn-drying method. At the beginning of the feeding trial, 19 lactating Holstein cows were allocated to one of two groups, one control (nine cows) and one experimental group (10 cows) and were fed the respective forage plus a fixed amount of concentrate [3.6 kg d−1; dry matter (DM) basis]. After a 14-d adaptation period, data were collected over 21 consecutive days. Covariate data of cows were collected prior to the experimental feeding period, over a time span of 9 d, and included in the statistical model. Results revealed that control and experimental hay showed significant (P&lt; 0.05) differences in the nutrient profile. However, the magnitude of these differences was not enough to affect intakes of hay (18.4 ± 0.29 kg DM d−1), total dietary energy or chewing activity, but did lead to a decreased intake of water-soluble carbohydrates and an increased crude protein intake, thus affecting ruminal nitrogen balance (P&lt; 0.01). This resulted in a higher milk urea content [23.3vs17.9 mg (100 mL)−1;P&lt; 0.01] in cows fed the experimental hay, whereas other milk performance parameters remained unaffected. In conclusion, the use of the impeller mowing conditioner did not affect the overall forage utilization by cows when the diet contained about 16% concentrate (DM basis). As this is the first study dealing with the effects of an impeller mowing conditioner on cows' responses, future research should consider investigating the effects of mowing conditioners when cows are fed only forage or diets with lower concentrate amounts.

Effects of a nitrogen-based supplement on intake, live weight and body energy reserves in breeding &lt;i&gt;Bos indicus&lt;/i&gt; cross cows

Breeding cows grazing seasonally dry rangelands usually lose substantial live weight (LW) during the dry season, when in late pregnancy. An experiment investigated the effects of feeding a N-based supplement to cows in late pregnancy on voluntary intake, total live weight (T-LW), body condition score (CS) and estimated body net energy content (Body-NE), as well as carry-over effects during lactation. In Phase A for 139 days from mid-pregnancy, mature Bos indicus cross breeders [initially 438 kg T-LW and 5.7 CS units (9-point scale)] were fed in pens on low quality tropical grass hay alone (Control) or with a N supplement (Supplemented). Most (17/22) of the cows calved during this interval. Voluntary hay intake averaged 6.74 g DM/kg T-LW/d in Control cows, and was increased by 35% (P&lt;0.001) when supplement was fed. As a result, feeding supplement reduced loss in conceptus-free live weight (CF-LW) by 30% (from 1.11 kg/d to 0.78 kg/d; P&lt;0.001) and in Body-NE by 20% (from 26.6 to 21.2 MJ NE/d; P = 0.007). Control cows mobilized 24% of maternal LW and 32% of body energy when fed low quality hay during late pregnancy, and these losses were substantially reduced when a N-based supplement was fed. During Phase B, when the lactating cows with their calves grazed a high quality rainy season grass-Stylosanthes pasture, the previously supplemented cows produced more milk (P = 0.065) and their calves grew faster (P = 0.077) in early lactation than Control cows. In addition, during early lactation Control cows exhibited compensatory LW gain relative to the Supplemented cows (0.80 vs. 0.43 kg/d, respectively; P&lt;0.001) and there was no discernable weight difference between the groups by 205 days of lactation. In conclusion the losses in LW and body energy reserves by late pregnant cows fed low quality tropical grass hay were substantially reduced by a N supplement, but the differences were not maintained when the cows subsequently grazed high quality pasture.

EFFECTS OF ENERGY AND PROTEIN LEVELS ON FEED INTAKE AND NUTRIENT UTILIZATION BY YANKASA LAMBS

TWENTY yearling Yankasa lambs were fed 2 levels of energy (2.4 and 2.9 ME Mcal/kg) and 2 levels of protein (11.3 and 16. 1%) under each energy level for 100 days to study the effects of feed intake, digestibility and nutrient utilization. Groundnut top hay was the basal roughage while maize, wheat bran and cotton seed cake were the energy and protein supplements in different proportions. Hay intake decreased with increase in protein level. Dry matter digestibility significantly (P/0.05) increased with increase in both energy and protein levels. Crude protein digestibility was significantly (P/0.01) affected by protein level but not by energy level. Crude fibre digestibility was depressed in the high-energy-high protein diet. The consumption of nutrients tended to be more on the high energy rations. Nitrogen retention was also significantly (P/0.05) higher on the high energy rations. Liveweight gain was highest in the low energy/high protein group (79.4g/day) and lowest in the low energy/low protein group (56.4g/day). Within each energy level, liveweight gains increased with increase in protein level. Animals fed high energy rations required more protein than those on low energy rations.

Evaluating digestibility and toxicity of native warm-season grasses for equines.

Introduced cool-season grasses are dominant in Virginia’s grasslands, but their high digestible energy and nonstructural carbohydrate (NSC) levels pose a risk for horses prone to obesity and laminitis. Native warm-season grasses (NWSGs) have lower digestible energy and NSC levels that may be more suitable for horses susceptible to laminitis. Although NWSGs have desirable characteristics, they are novel forages for horses. Little is known about NWSG intake or potential toxicity to horses or how grazing by horses may affect NWSG swards. The overall objectives of this research were to 1) assess voluntary intake, toxicological response, and apparent digestibility of NWSG hays fed to horses; and 2) evaluate the characteristics of three NWSG species under equine grazing. For the first objective, a hay feeding trial using indiangrass (IG) (Sorghastrum nutans) and big bluestem (BB) (Andropogon gerardii) was conducted with nine Thoroughbred geldings in a replicated 3 × 3 Latin square design. Voluntary dry matter intake of IG and BB hays by horses were 1.3% and 1.1% of BW/d, lower than orchardgrass (Dactylis glomerata), an introduced cool-season grass, at 1.7% of BW/d (P = 0.0020). Biomarkers for hepatotoxicity remained within acceptable ranges for all treatments. Apparent dry matter digestibility (DMD) did not differ among hays, ranging from 39% to 43%. NSC levels ranged from 4.4% to 5.4%, below maximum recommended concentrations for horses susceptible to laminitis. For the second objective, a grazing trial was conducted comparing IG, BB, and eastern gamagrass (EG) (Tripsacum dactyloides) yields, forage losses, changes in vegetative composition, and effects on equine bodyweight. Nine, 0.1-ha plots were seeded with one of the three native grass treatments, and each plot was grazed by one Thoroughbred gelding in two grazing bouts, one in July and another in September 2019. IG had the greatest available forage, at 4,340 kg/ha, compared with 3,590 kg/ha from BB (P < 0.0001). EG plots established poorly, and had only 650 kg/ha available forage during the experiment. Grazing reduced standing cover of native grasses in IG and BB treatments by about 30%. Horses lost 0.5–1.5 kg BW/d on all treatments. Findings suggest IG and BB merit further consideration as forages for horses susceptible to obesity and pasture-associated laminitis.

PSX-36 Late-Breaking Abstract: Effect of increasing levels of soy hulls in finishing diets of feedlot cattle offered free-choice hay on performance, roughage intake and carcass characteristics

Abstract The objective of this study was to evaluate the effect of increasing quantity of soy-hulls in diets of feedlot cattle offered free-choice hay on finishing performance, roughage intake, and carcass characteristics. Sixty heifers and 54 steers, Angus*Simangus-crossbreds, were used in a randomized complete block design. Cattle were stratified by sex and weight and randomly assigned to 1 of 12 pens. Treatment 1 consisted of 5% soy hulls (SH; 5%SH), 70% cracked corn (CC), 15% dry distiller grains with soluble (DDGS), 10% mineral supplement (SUP). Treatments 2 (10%SH) and 3 (15%SH) included an additional 5% and 10% SH in place of CC, respectively. Hay was offered ad libitum and separate from the concentrates in different bunks, both concentrate and forage were fed in GrowSafe units. Data were analyzed as a complete block design and mean differences in group means were determined using polynomial contrast [lineal (L) and quadratic (Q)]. There was a quadratic effect of soy hull inclusion on final body weight (fBW) and concentrate intake (Q-P ˂ 0.05); 5%SH and 15%SH had a greater fBW and concentrate intake compared to those fed 10%SH. Gain to feed ratio was not affected by treatments (L-P ≥ 0.33). There was a linear effect of SH on hay intake (L-P ˂ 0.05) with cattle fed 5%SH consuming less hay than those fed 15%SH. There was no effect on ribeye area, yield grade, or backfat (L-P ≥ 0.35; Q-P ≥ 0.14). Hot carcass weight tended to quadratically respond to dietary treatments (Q-P &amp;lt; 0.10), while marbling score tended to be linearly decreased by increased SH inclusion (L-P = 0.09). Kidney-pelvic-heart fat was linearly decreased by increased SH inclusion (L-P ˂ 0.05). Results indicate that non-roughage NDF from by-products can effectively contribute to a reduction of roughage utilization in feedlot diets without compromising growth performance or carcass characteristics.

PSVII-23 Using low-moisture molasses-based blocks to supplement Ca salts of soybean oil to forage-fed beef cows

Abstract This experiment compared plasma fatty acid (FA) profile of forage-fed beef cows receiving a molasses-based supplement enriched with Ca salts of soybean oil [(CSSO); 24.7% of dry matter (DM)] via a self-fed low-moisture block (LMB) or hand-fed granular concentrate daily (CONC). Thirty-six cows were allocated to 1 of 9 drylot pens, which were enrolled in a replicated 3 x 2 Latin square design with 2 periods of 42 d. Pens were randomly assigned to receive 1 of the 3 treatments, in a manner that pens did not receive the same treatment in both periods. Cows received hay for ad libitum consumption during the study. Hay intake was recorded daily from d 0 to 42, and LMB intake was recorded from d 14 to 42. The CONC was offered at 0.420 kg/cow daily (DM basis) from d 0 to 13, and then adjusted (d 14 to 42) to match LMB intake. Average LMB intake during the initial 13 d was 0.846 ± 0.107 kg/cow daily (DM basis). Supplement DM intake did not differ (P = 0.39) between LMB and CONC cows from d 14 to 42. No treatments effects were noted (P ≥ 0.40) for hay intake, BCS, and BW. Plasma FA profile did not differ (P ≥ 0.20) between treatments on d 0. From d 14 to 42, plasma concentrations of linoleic acid, ω-6 polyunsaturated FA, and total FA were greater (P &amp;lt; 0.01) in CONC and LMB vs. NOSUPP cows. Plasma concentrations of these FA were also greater (P ≤ 0.03) in LMB vs. CONC cows on d 14, but did not differ (P ≥ 0.35) on d 28 and 42. Inclusion of CSSO into LMB resulted in similar incorporation of ω-6 polyunsaturated and total FA in the circulation compared with CONC offered at the same daily rate.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ВЫРАЩИВАНИЯ ТЕЛЯТ В РАЗНЫХ ХОЗЯЙСТВАХ

Numerous studies have shown that animals with the same genetic potential can differ in productiveness. In this regard, specialists in this industry, when predicting the milk productivity of adult animals in the process of raising young cattle, divide rearing into separate periods. In order to study the conditions for growing dairy calves, a comparative analysis of the conditions for keeping and feeding calves in two farms of the Republic of Tyva was carried out. The conditions of growing calves in the dairy period in the conditions of different farms with the same breed composition of cattle were studied. A comparative analysis of the influence of the composition and level of the diet on the growth of young animals is given. Calves of both groups by birth weight at birth did not have significant differences: they were 0.05-0.07 kg. In dairy farms MUP “KaaKhemsky” and “OOO Turanskoye” young cattle from birth to 6 months are kept in separate rooms. There are no significant differences in the calf feeding schedule. In the Municipal Unitary Enterprise “Kaa-Khemsky” feeding with haylage of young animals is introduced from two months of age; at the farm of “OOO Turanskoye” silage has been given to calves from 4 months. However, from 4 months to six months of age, they showed a significant difference in the increase in live weight. At 4 months, the difference averaged 4.27 kg, at 5 and 6 months – 6.39 and 8.59 kg, respectively. As a result of the studies, it was concluded that a decrease in the drinking of whole milk and the introduction of a substitute at its early, three-month-old age, which are compensated by a large intake of hay, feed and silage, do not provide a high average daily gain in live weight of the growing organism of young cattle.

Sütten Kesilmiş Oğlaklarda Yeme Maya Destekli Bakteriyel Probiyotik İlavesinin Performans Üzerine Etkileri

Bu araştırmanın amacı, sütten kesimden sonra oğlakların beslenmesinde konsantre yeme maya destekli bakteriyel probiyotik ilavesinin canlı ağırlık, canlı ağırlık artışı, yem tüketimi ve yemden yararlanma üzerine etkilerinin belirlenmesidir. Araştırmada ortalama canlı ağırlığı 19.19±1.00 kg olan 2.5-3 aylık yaşlı karışık cinsiyette 18 baş Akkeçi oğlağı kullanılmıştır. Oğlaklar sütten kesimden sonra tesadüfi olarak kontrol ve muamele olarak 2 gruba ayrılmıştır. Kontrol grubunda bulunan oğlaklar, büyütme yemine su püskürtülerek (plasebo) hazırlanan konsantre yemler ile, muamele grubunda bulunan oğlaklar ise maya destekli bakteriyel probiyotik(sıvı) ilaveli konsantre yemler ile beslenmişlerdir. Püskürtme yöntemi ile yeme günlük olarak ilave edilen probiyotik karışımı, Lactobacillus, Enterococcus, Pediococcus, Bacillus bakterileri ile birlikte Saccharomyces cerevisiae mayasını da içeren ticari bir preparattır. Deneme süresince oğlaklara büyütme yemi (pelet formda) ve su ad-libitum olarak verilmiş, kuru yonca otu tüketim miktarları ise canlı ağırlığın % 1’i olacak şekilde düzenlenmiştir. Araştırma, yeme alıştırma dönemi ile (15 gün) birlikte 75 gün sürdürülmüştür. Araştırmada oğlakların canlı ağırlıkları haftalık yapılan tartımlarla sabah yemlemesinden önce belirlenmiştir. Oğlakların konsantre yem ve kuru yonca otu tüketimleri günlük olarak tespit edilmiştir. Araştırma sonunda canlı ağırlık ve canlı ağırlık artışı bakımından probiyotik ilavesinin etkisi bulunmamıştır (P&gt;0.05). Cinsiyetin etkisi önemli bulunmuş, 2.haftadan itibaren erkekler dişilere göre daha fazla canlı ağırlık artışı sağlamışlardır (P

Using low-moisture molasses-based blocks to supplement Ca salts of soybean oil to forage-fed beef cows.

This experiment compared plasma fatty acid (FA) profile of forage-fed beef cows receiving a molasses-based supplement enriched with Ca salts of soybean oil [CSSO; 24.7% of dry matter (DM)] via a self-fed low-moisture block (LMB) or hand-fed granular concentrate daily (CONC). Thirty-six nonlactating, nonpregnant, multiparous beef cows were blocked by age (three blocks), ranked within blocks by body weight (BW) and body condition score (BCS), and allocated to 1 of three drylot pens (27 × 10 m) per block. Nine pens with four cows each were enrolled in a replicated 3 × 2 Latin square design with two periods of 42 d, and a 21-d washout interval. On day 0, pens within each block were randomly assigned to receive one of the three treatments, in a manner that pens did not receive the same treatment in both periods (total n = 6 pens per treatment). Cows received hay (Cynodon dactylon), water, and a mineral–vitamin mix for ad libitum consumption during the study. Hay intake was recorded daily from days 0 to 42, and LMB intake was recorded from days 14 to 42 to allow cows to adapt to supplement with minimal interference from days 0 to 13. The CONC was offered at 0.420 kg/cow daily (DM basis) from days 0 to 13 and then adjusted (days 14 to 42) to match LMB intake. Cow BW and BCS were recorded, and blood samples were collected on days 0, 14, 28, and 42. Average LMB intake during the initial 13 d was 0.846 ± 0.107 kg/cow daily (DM basis). Supplement DM intake did not differ (P = 0.39) between LMB and CONC cows from days 14 to 42 as designed (0.570 vs. 0.583 kg/d, respectively; SEM = 0.011), despite a greater variation in daily intake of LMB vs. CONC (treatment × day interaction; P < 0.01). No treatments effects were noted (P ≥ 0.40) for hay intake, BCS, and BW. Treatment × day interactions were detected (P ≤ 0.01) for plasma concentrations of ω-6 polyunsaturated FA and total FA. On day 0, plasma FA profile did not differ (P ≥ 0.20) between treatments. From days 14 to 42, plasma concentrations of linoleic acid, ω-6 polyunsaturated FA, and total FA were greater (P < 0.01) in CONC and LMB vs. NOSUPP cows. Plasma concentrations of these FA were also greater (P ≤ 0.03) in LMB vs. CONC cows on day 14, but did not differ (P ≥ 0.35) on days 28 and 42. These results indicate that CSSO inclusion into LMB resulted in similar incorporation of ω-6 polyunsaturated and total FA in the circulation compared with CONC offered at the same daily rate. Hence, the use of self-fed LMB appears to be a valid strategy to provide CSSO to forage-fed beef cattle with reduced labor needs.

Influence of Corymbia citriodora leaf extract on growth performance, ruminal fermentation, nutrient digestibility, plasma antioxidant activity and faecal bacteria in young calves

The effect of Corymbia citriodora leaf extract on growth performance, nutrient digestibilities, rumen fermentation, and health status of male crossbred Holstein calves was evaluated in the present study. Three treatments were evaluated by mixing C. citriodora leaf extract (CC) at 0 (CC0), 10 (CC10) or 20 (CC20) ml in the milk of the Holstein calves for 15 weeks. By GC/MS analysis, the main compounds identified in C. citriodora leaf aqueous extract were methyl(Z)-9-oleate (12.69 %), oleic acid (12.13 %), 2-methylene-5α-cholestan-3β-ol (11.18 %), and methyl 12,15-octadecadiynoate (7.73 %). A significant decrease was noticed in intakes of milk, calf starter, hay, and total dry matter (DM) in the calves supplemented with leaf extract at 20 ml. The supplementation of leaf extract at 10 ml/calf did not affect the final body weights, average daily gain, and feed conversion ratio, whereas the extract showed a quadratic decrease (P < 0.001) in the body weight gains and feed conversion ratio at 20 ml/calf. Digestibility of DM, crude protein, neutral detergent fiber, and acid detergent fiber decreased quadratically (P < 0.001) with supplementation of C. citriodora leaf extract in milk. The rumen pH and total volatile fatty acid concentration were similar among the treatments, while the molar proportions of volatile fatty acids differed with a decrease in acetate and butyrate and an increase in propionate concentrations in leaf extract supplemented diets. Further, ruminal NH3-N concentration showed a quadratic decrease with increasing levels of leaf extract supplementation. Feeding C. citriodora leaf extract resulted in lower dry matter and neutral detergent fiber degradation, acetate to propionate ratio, protozoan population, and methane production compared to control. Apart from increasing the plasma antioxidant enzymatic activities, the leaf extract supplementation, irrespective of the dosage, showed a marked reduction in faecal pathogenic bacterial counts, indicating an improved health status. The C. citriodora leaf extract could be supplemented at 10 ml/calf/day to improve the health status and manipulate rumen fermentation in mitigating methane production without any negative effects on the growth performance of calves.