Hay Intake Research Articles

PSXII-26 The influence of protein supplementation in beef cows during early lactation on growth performance, carcass characteristic and meat quality of progeny

Abstract At 11 ± 4 d of lactation, 30 multiparous Angus cows [body weight (BW) = 476 ± 17 kg, body condition score (BCS) = 4.5 ± 0.3) were stratified by BW and allotted in 6 pens (5 cows/pen). During 75 d of experiment, all pens received ad libitum low quality hay (Panicum italicum; 54.7% TDN, 6.1% CP DM basis) and were randomly assigned to one of two treatments: 1) PS; cows received ad libitum 30% CP supplement including an intake limiter component (Controlmix, Nutralmix SRL, Argentina), or 2) NS; cows were not supplemented. After the experimental period, dams and their calves (PS: 7 males and 8 females; NS: 8 males and 7 females) were managed on improved pastures as a single group until weaning at 213 d of age. After weaning, heifer and steer calves were reared on improved pastures until 448 d of age, then placed into a feedlot with a finishing diet during 73 d until slaughter. Pens were considered the experimental unit and data were analyzed using the PROC MIXED of SAS, considering treatment and sex as a fixed effects and pen as a random effect. Overage dry matter intake (DMI) of hay was not affected by treatments (P > 0.10), and DMI of supplement in PS cows was 4.4 kgּ cow-1ּ d-1. Milk production was greater in PS than NS cows (PS: 5.3, NS: 3.6 kgּ cow-1ּ d-1; P < 0.01). Progeny from PS cows increased BW at weaning (PS: 180, NS: 141 kg; P < 0.01), BW at initial feedlot phase (PS: 300, NS: 252 kg; P = 0.01) and final BW (PS: 415, NS: 354 kg; P = 0.01). After slaughter, progeny from PS cows tended to have increased dressing percentage (PS: 59.0, NS: 58.1%; P = 0.09), had an increased hot carcass weight (PS: 227, NS: 191 kg; P < 0.01), and increased Longissimus muscle (LM) area (PS: 68.5, NS: 60.1 cm2; P = 0.02), while rib fat thickness was not affected by treatments (PS: 7.8, NS: 7.6 mm; P = 0.68). There was no effect of protein supplementation on color (L*, a*, b*) and pH of LM at 24 h postmortem (P > 0.10). In addition, moisture, ether extract and shear force of LM after 4 d of aging were similar between treatments (P > 0.10). There was no treatment × sex interaction for any variables (P > 0.10). This study showed that protein supplementation during early lactation improved growth performance and carcass quality, but did not result in enhanced meat quality of progeny.

Potential of feeding microwave-treated forage hays to improve sheep intake, digestion, nitrogen partitioning, and metabolism

Microwave (MW) treatment has been suggested to improve forage hays' nutritive value and sheep growth performance. However, the extent to which the MW-treated forage hay affects apparent digestibility and nitrogen partitioning is not documented. This study examined the potential to use the MW as a novel thermal treatment to improve forage hay intake, digestibility, and nitrogen utilisation of sheep. A total of 24 merino rams (18 months of age, 42 ± 2.0 kg initial body weight) were randomly divided into four dietary treatments: Control lucerne hay (CLH), MW-treated lucerne hay (MLH), Control wheat hay (CWH), and MW-treated wheat hay (MWH). The study had 14 days adaption and 7 7-day sample collection period, with 6 sheep replicates/treatment. Feed, faeces, urine, and blood plasma samples were collected. Higher dry matter (DM) intake was observed in MLH vs. CLH (P < 0.001). The DM and organic matter digestibility both increased by 8 % in MLH compared to CLH (P <0.001). The digestibility of neutral detergent fibre (NDF), acid detergent fibre (ADF), and nitrogen increased by 12 %, 9 %, and 10 %, respectively in MLH compared to CLH (P < 0.001). The MLH-feed sheep showed higher nitrogen retention (P = 0.037) and microbial nitrogen synthesis (P = 0.047) compared to CLH-fed sheep. A limited effect was observed in CWH vs. MWH, with only ADF digestibility (P = 0.023) and plasma glucose (P < 0.05) being higher in sheep fed with MWH. Electron microscope images showed clear cell microstructure destruction (P <0.001) due to MW treatment in lucerne hay but there was no difference observed in wheat hay. The result provided first-hand comprehensive data to quantify MW treatment's effect on hay quality and sheep performance, with potential mechanisms explained underpinning the observed changes.

294 Development of a model to predict forage intake and growth of bottle-fed Holstein calves

Abstract Models to predict intake and growth of preweaning calves have received less attention than postweaning calves. The objective was to develop a model to predict forage intake and growth of bottle-fed Holstein calves. Data on milk intake, alfalfa hay intake, and body weight (BW) of 40 Holstein calves from birth to 200 d of age were acquired from Abdelsamei (1989). Milk and forage intake equations were those used by Lancaster et. al. (2021; 10.1093/jas/skaa406). NASEM growth equation evaluation and new equation development were performed using a dataset compiled from the literature by Hildebrand et al. (2022; 10.1093/jas/skac064.321). The mean absolute error to predict milk intake was less for WOOD at peak milk less than 10.88 kg/d, and was less for NASEM at peak milk greater than 10.88 kg/d. A combination of NASEM and WOOD milk yield equations to predict milk intake resulted in CCC of 0.969 and MB of -0.74% and was used to predict milk intake in subsequent analyses. Prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 had CCC of 0.878, 0.920, 0.729, 0.874, and 0.234 with MB of -17.49, -1.58, -64.40, -35.60, and -341.16%, respectively. Prediction of BW for the same intake equations with the NASEM growth equation had CCC of 0.876, 0.929, 0.819, 0.864, and 0.402 with MB of -21.54, -14.67, -30.10, -25.13, and -99.78%, respectively. With observed BW, prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 resulted in CCC of 0.935, 0.936, 0.958, 0.964, and 0.640 with MB of -0.55, 6.57, -11.90, -8.83, and -92.26%, respectively, indicating high precision and moderate accuracy. With observed forage intake, prediction of BW by the NASEM growth equation resulted in CCC of 0.926 and MB of -17.08% indicating high precision and poor accuracy. Evaluation of the NASEM growth equation in Holstein cattle resulted in CCC of 0.329 and MB of 61.47%. A new growth equation was developed: EBG, kg/d = 0.78498 ± 0.24035*RE, Mcal/d^(0.78500 ± 0.06033)*EBW, kg^(-0.14323 ± 0.0742) with RMSE = 0.0599 ± 0.0207 and R2 = 0.8795 ± 0.1078. With observed forage intake, prediction of BW with the new growth equation resulted in CCC of 0.992 and MB of -0.11%. With the new growth equation, prediction of forage intake by TED06, BAK76, TED09A, TED09B, and HOL82 resulted in CCC of 0.914, 0.766, 0.881, 0.901, and 0.412 with MB of 15.47, 40.53, 18.11, 17.02, and -172.88%, respectively. Prediction of BW resulted in CCC of 0.978, 0.940, 0.968, 0.969, and 0.701 with MB of 2.83, 8.91, 3.87, 3.92, and -38.73%. In conclusion, prediction of forage intake and BW in Holstein calves were hindered by use of the NASEM growth equation, and a new growth equation more precisely and accurately predicted forage intake and body weight.

Effects of altering diet carbohydrate profile and physical form on zoo-housed giraffe Giraffa camelopardalis reticulata.

Unlike wild giraffe that primarily consume low starch browse, the preference of zoo-housed giraffe for consuming supplemental feeds over forage could increase the risk of digestive disorders such as ruminal acidosis. Our objective was to evaluate the effects of modifying a supplemental feed's non-fibre carbohydrate profile and physical form on nutritional, behavioural, and blood measures of giraffe in a zoological setting. Six non-lactating, adult, female reticulated giraffes were used in a two-pen modified reversal study using two dietary treatments in seven 21-day periods with data collected on days 15-21. Dietary treatments were a control feed comprised of commercially available products used at the time as the giraffe feed (GF) and an unpelleted experimental feed (EF). On a dry matter basis, GF and EF, respectively, contained 17.0% and 17.4% crude protein, 14.2% and 1.5% starch, 14.9% and 21.3% ethanol-soluble carbohydrates, 22.9% and 26.0% acid detergent fibre (ADF)and 9.50% and 14.9% ND-soluble fibre (NDSF), with modulus of fineness values of 3.62 and 4.82. Supplemental feeds, alfalfa hay, salt, and water were available for ad libitum consumption. Significance was declared at p ≤ 0.05. Intakes of hay, supplemental feeds, and total feed did not differ by diet (p > 0.28), though intakes of starch (0.93 and 0.12 kg; p = 0.05) and ADF (1.83 and 2.23 kg; p = 0.04) differed between GF and EFrespectively. Giraffe behaviour values (min/48 h) were greater with EF for total eating (p = 0.04); diets were not detected as different for engagement in oral stereotypes (GF = 433, EF = 318 min/48 h; p = 0.22). Blood glucose was higher on GF than EF (99.0 and 82.3 mg/dL; p = 0.03). The lower EF blood glucose value is more similar to ranges reported for domesticated ruminants. No differences were detected for changes in body weight or body condition score in the 21-day periods (p > 0.32). Modification of supplemental feed carbohydrate profile and physical form can influence behaviour and blood glucose values of zoo-housed giraffe.

Effect of odontoplasty on intake, nutrient digestibility, and intake time of tifton hay in ponies

We aimed to evaluate the effects of dental correction on voluntary nutrient intake, time of intake, apparent digestibility and fecal particle size in Brazilian ponies. Twelve mares, with no history of previous dental treatments, housed in individual pens and fed a diet based on tifton 85 were used. The study comprised two consecutive experimental phases, pre and post dental treatment. Each phase consisted of 15 days for adaptation to the pen and treatment and 5 days for data collection, totaling 20 days. To calculate nutrient intake and digestibility coefficients, samples of diets, leftovers, and feces were analyzed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude fat (CF), mineral matter (MM), organic matter (OM), and non-fiber carbohydrates (NFC). Food intake time was recorded using a digital video recorder. Fecal particles were analyzed by wet sieving. Dental correction did not influence the intake of DM, CP, NDF, CF, and OM by the animals. However, there was an increase in NFC intake from 0.12 kg to 0.14 kg and in food intake time from 654.50 ± 138.98 to 774.95 ± 167.14. There was a decrease in the digestibility of CP from 0.08 kg to 0.04 kg and an increase in the digestibility of NDF from 0.65 kg to 0.82 kg. Although odontoplasty increased the time of hay intake and the digestibility of the fibrous fractions of the feed of ponies, it did not influence the intake of nutrients and the size of the fecal particles.

Effects of meloxicam on the welfare of Holstein calves from 6 weeks to 6 months old undergoing amputation dehorning

Amputation dehorning (AD) is a common practice performed on calves, causing harmful effects such as pain, distress, anxiety, and fear. These effects extend to behavioral, physiological, and hematological responses, prompting serious ethical concerns regarding animal welfare, even when performed with local anesthesia. Meloxicam, a nonsteroidal anti-inflammatory drug, has been widely used to mitigate the side effects of dehorning and disbudding in calves. However, there is a notable gap in research regarding the effects of meloxicam on calves aged 6 wk to 6 mo undergoing AD procedures. This study was designed to assess the effectiveness of co-administering meloxicam with lidocaine, a cornual nerve anesthetic, in alleviating the adverse effects caused by the AD procedure in calves within this age range, compared with the use of lidocaine alone. Thirty Holstein calves were enrolled and randomly divided into 2 groups. The first group received a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 0.9% saline at a dose of 0.025 mL/kg in the neck, administered 10 min before the AD procedure. The second group received a combination of lidocaine and meloxicam: a subcutaneous injection of 5 mL of lidocaine in the horn area and a subcutaneous injection of 20 mg/mL meloxicam at a dose of 0.025 mL/kg in the neck, also administered 10 min before the AD procedure. To avoid subjective bias, the researchers were blinded to the treatment groups. Pain-related behaviors, including tail flicking, head shaking, ear flicking, head rubbing, head crossing bar, and kicking, were observed, and physiological parameters, including heart rate, rectal temperature, respiration rate, mechanical nociceptive threshold (MNT), daily active steps, and food intake were monitored. Hematological conditions were determined using enzyme-linked immunosorbent assays and routine blood tests. The data were processed using a generalized linear mixed model. The outcomes demonstrated that the AD procedure increased the frequencies of ear flicking and resulted in rises in the respiration rate, heart rate, rectal temperature, and daily active steps. It also led to decreases in total food intake, forage intake, hay intake, MNT, and increased concentrations of prostaglandin E2 (PgE2), IL-1β, tumor necrosis factor-α (TNF-α), nitric oxide (NO), and malondialdehyde, as well as glutathione peroxidase activity. However, calves that received meloxicam treatment showed significant improvements in response to the AD procedure, including lower respiration rates, heart rates, and rectal temperatures; higher MNT; and lower intermediate cell ratio. They also had higher red blood counts, hemoglobin levels, hematocrit values; larger mean platelet volumes; and lower concentrations of PgE2, IL-1β, TNF-α, and NO. These results suggest that co-administration of lidocaine and meloxicam may aid in mitigating the adverse effects induced by the AD procedure on these calves, thereby supporting the use of meloxicam in conjunction with a local anesthetic in AD procedures for calves aged 6 wk to 6 mo.

PSII-2 Effects of Natural Sources of Brackish/Saline Water on Water and Feed Intake, Digestion, Physiological Conditions, and Performance of Yearling Meat Goats

Abstract This experiment was aimed to determine how variables such as water intake, feed intake, ruminal conditions, digestion, blood constituent levels, energy metabolism, and performance of yearling meat goats are influenced by different natural sources of brackish/saline water. Two animal types (AT), 18 Boer (BOE) and 18 Spanish (SPA) doelings, with the age of 8.9 ± 0.306, and 9.7 ± 0.212 months, respectively were used for the experiment which lasted 17 weeks (16 weeks for the experiment and 1 week of adaptation). Drinking water treatments were fresh water (FRW), West pasture Brackish water (BRW), water classified by USGS as group 1 (GR-1), 2 (GR-2), 3 (GR-3), and the last one did not fit well with any USGS group (G-UC). Animals were fed a medium-quality grass hay primarily consisting of lespedeza and with some Johnson grass (12.2% CP, and 48% NDF on a DM basis) and a supplement was provided at 0.2% BW (DM basis) to supply trace minerals, vitamins, and protein. Average daily gain was similar (P &amp;gt; 0.05) among treatments (16.3, 20.1, 21.1, 20.7, 23.3, and 26.5 g/day SEM = 6.378 for FRW, BRW, GR-1, GR-2, GR-3 and G-UC, respectively), and between AT (19.9 and 22.7 g/day SEM = 3.90 for BOE and SPA, respectively). Treatment did not affect water (P = 0.752; 830, 767, 821, 796, 855, and 857 g/day; SEM = 47.86) or hay intake (P = 0.862; 682, 654, 641, 674, 650, and 689 g/day SEM = 31.72), and also there were no differences between AT in intakes of water (P = 0.157; 850 and 793 g/day; SEM = 27.63) and hay (P = 0.165; 684 and 647 g/day SEM = 18.31) for BOE and SPA, respectively. Treatment had no effect on blood packed cell volume (PCV; P = 0.224; 28, 27.4, 29.7, 25.7, 26.2, 27.5%), hemoglobin concentration (tHb; P = 0.489; 11.2, 10.6, 11.2, 10.4, 10.3, 10.6 g/dL) or osmolality (310, 310, 309, 310, 309, and 309 mOsm/L) for FRW, BRW, GR-1, GR-2, GR-3 and G-UC, respectively. But there were differences between AT in PCV (P &amp;lt; 0.001; 24.8 and 30%) and tHb (P &amp;lt; 0.001; 9.71 and 11.7 g/dL) for BOE and SPA, respectively. Animal types differed in their heat (P = 0.046; 3.94 and 3.70 MJ/day; SEM = 0.081) and methane production (P &amp;lt; 0.001; 0.50 and 0.42 MJ/day; SEM = 0.014) for BOE and SPA, respectively; but treatment did not affect heat energy (P = 0.861; 3.84, 3.77, 3.67, 3.88, 3.88, 3.86 MJ/day SEM = 0.1409) or methane energy (P = 0.634; 0.46, 0.43, 0.45, 0.47, 0.48, 0.48; SEM = 0.0241) for FRW, BRW, GR-1, GR-2, GR-3 and G-UC, respectively. Though differences existed between animal types, considering lack of effect of drinking water used in the studied parameters, the animals seemed resilient to the brackish water from West pasture, USGS group 1, 2, 3 and the unclassified water.

Peripartum factors associated with variation in voluntary postpartum hay intake in dairy cows

The objective of this research was to assess variation in postpartum hay intake when offered alongside total mixed ration (TMR) as free choice, and identify factors related to the hay intake. Twenty multiparous cows were fed a closeup TMR (21.5% starch, 39.1% neutral detergent fiber [NDF] on a dry matter [DM] basis). After calving, cows were offered free choice timothy hay (61.6% NDF, 9.6% crude protein) in addition to a fresh cow TMR (26.8% starch, 33.0% NDF) for the first 5 d postpartum. Cows were fed individually with separate mangers for TMR and hay, each offered ad libitum. Prepartum DM intake (DMI) was recorded, and baseline blood samples were collected after calving, but before the first postpartum feeding. Free choice hay intake ranged from 0 to 4.7 kg/d (DM basis) or 0 to 55.2% (% of total DMI). Cows that consumed more hay (% of total DMI) from d 1 through 5 postpartum had lower DMI 2 d before calving (r = −0.63), and greater baseline concentrations of plasma β-hydroxybutyrate (r = 0.60) and serum haptoglobin (r = 0.68). Additionally, hay intake (% of total DMI) from d 1 through 5 postpartum tended to be positively related to baseline plasma fatty acid concentration (r = 0.41). These findings suggest that cows with lower intake before calving and cows with greater ketone production and inflammation at calving may consume more hay, when offered separate from TMR.

Effects of offering free-choice hay for the first 5 days postpartum on productivity, serum inflammatory markers, gut permeability, and colon gene expression in fresh dairy cows

The objective of the present study was to evaluate the effects of offering free-choice hay to cows during the first 5 d immediately after calving on feed intake, milk yield, plasma metabolites, serum inflammatory markers, rumination, gut permeability, and colon gene expression. It was hypothesized that cows offered free-choice hay would have lower gut permeability, lower inflammation, and higher milk production, compared with cows not offered hay. Thirty-two multiparous cows were fed a closeup total mixed ration (TMR; 21.5% starch, 32.1% forage neutral detergent fiber [NDF] on a dry matter basis) until calving. In the postpartum period, all cows were fed a fresh cow TMR (26.8% starch and 23.4% forage NDF) from calving until 21 DIM, and were assigned randomly to receive 1 of 2 treatments as follows: (1) free-choice timothy hay (61.6% NDF; 9.6% crude protein), offered outside of the TMR in a separate manger, for the first 5 d postpartum (FCH; n = 20), or 2) no free-choice hay (NH; n = 12). The FCH cows tended to have lower serum haptoglobin concentration on d 3, compared with NH (0.95 vs. 1.52 mg/mL). Within the FCH group, cows with greater hay intake had a smaller increase in serum amyloid A from d 1 to 3 after calving (r = 0.37), and tended to have a smaller increase in serum haptoglobin concentration (r = 0.36). Cows in the FCH group had a lower ratio of starch intake (kg) to forage NDF intake (kg) on d 1 and 2, compared with NH (0.91 vs. 1.14 ± 0.03), and cows that had a lower starch:forage NDF ratio tended to have a smaller increase in serum haptoglobin concentration from d 1 to 3 after calving (r = 0.32). Cows in the FCH group had lower TMR dry matter intake (DMI; 15.0 vs. 17.1 ± 0.93 kg/d) and lower total DMI (TMR + hay DMI; 15.9 vs. 17.1 ± 0.87 kg/d), from d 1 to 5 when free-choice hay was offered, compared with NH. However, the hay treatment did not affect plasma energy metabolite concentration, gut permeability, colon gene expression, milk yield, rumination time, or change in body weight or body condition score. Overall, these findings suggest that offering free-choice hay for the first 5 d after calving may reduce serum inflammatory marker concentration, but milk yield may not increase, due to lower intake.

Fecal NIRS to estimate intake and diet composition in Sarda dairy ewes fed mixed diets or part-time grazing forage crops

Knowledge on the intake and diet composition is a key to efficiently and sustainably drive ruminant production systems. Near infra-red spectroscopy of fecal samples (F.NIRS) has been proposed as a tool to estimate intake, diet composition and digestibility of ruminants. This study was aimed at ascertaining if F.NIRS can precisely and accurately predict 1) individual dietary intake and composition in dairy sheep fed mixed diets in confinement; 2) group dietary intake and composition in grazing dairy ewes using spot sampled faeces. We used two main datasets consisting of pairs of NIRS fecal spectra and reference values for intake, nutrient digestibility and composition of the diet: STALL, based on the results of digestibility trials carried out on a total of 120 sheep individually fed mixed diets including fresh forages, hays and concentrates (29 diets) and GRAZE based on results of already published grazing experiments. GRAZE encompassed a total of 102 pairs of group fecal spectra and group reference values regarding 6 grazing treatments differing in forage species, supplementation type and access time to pasture, in which reference data were obtained by double weighing procedure for herbage intake and hand-plucking for herbage composition. Group fecal samples were collected the day after. Data of the two datasets were separately used to calibrate F.NIRS using partial least square regression analysis and subsequent cross-validation. The quality of calibrations was evaluated using the ratio performance deviation (RPDcv). The diet attributes showing RPDcv in a range good to excellent (RPD > 3) in cross-validation were submitted to a validation exercise, on a subset of data previously excluded from calibration. Validation performance were evaluated as RPDval. Under confined conditions, individual herbage intake was predicted with good precision R2val = 0.90 and accuracy, SEP = 11.6% (RDPval = 3.2). The intake of hay was also well predicted (R2val = 0.97, SEP = 9.9%, RPDval = 4.6), whereas that of concentrates was just fairly predicted with R2val = 0.88 but a lower accuracy (SEP = 26.7%, RPDval = 2.9). The estimation of individual diet composition (% ingredients) was excellent for herbage and hay and good for concentrate, with R2val = 0.97, SEP = 11.2% and RPDval = 4.9 for hay; R2val = 0.97, SEP = 6.7% and RPDval = 5.5 for herbage; and R2val = 0.95, SEP = 26.7% and RPDval = 4.5 for concentrates. Prediction of nutrient proportion in the diet (% DM) was good for NDF, ADF, EE (RPDval ≥ 3) but inadequate for NFC (RPDval = 1.5). Cross-validation models were rather imprecise for CP and OM. Individual digestibility coefficients were poorly estimated in cross-validation, being the best models those estimating the digestibility of NFC (R2cv = 0.83, SECV% = 2.3, RPDcv = 2.4) and ADF (R2cv = 0.81, SECV% = 9.3, RPDcv= 2.3). Under grazing conditions, after cross-validation all models showed RPD < 3. The group intake of herbage was estimated with a modest precision and accuracy (R2cv = 0.75, SECV% = 14.2, RPDcv = 2.0). The proportion of herbage in the diet and its NDF content showed a higher accuracy, and equal or better precision, although models were adequate only for rough screening (RPDcv = 2 and 2.3, respectively). To conclude, this research confirms for dairy sheep the usefulness of F.NIRS to estimate individual intake and individual diet composition in ruminants fed mixed diets in confinement. Moreover, this study shows a modest cross-validation performance of F.NIRS for estimating group average proportion of herbage and NDF in the diet of grazing ewes by spot-sampling their faeces. Further validation of these models is needed to assess the applicability of the above results to farm conditions.

Nutrient restriction during pregnancy and litter size affect the feeding behaviour, feed preference and welfare of the aged ewe’s offspring

The present work evaluates the effect of a nutrient maternal restriction induced by a lower forage allowance of natural grassland (LFA) and the type of birth [single (S) and twins (T)] and its interaction on the feed preference, the feeding behaviour, and welfare indicators of aged offspring ewes. A total of 28 Corriedale, seven years old, multiparous ewes in the anestrus period (spring) were used: 11 singles (S) and 4 twins (T) born to high forage allowance mothers (HFA: 10 – 12 DM/100 kg LW·day), and 9 S and 4 T born to LFA (5 – 8 DM/100 kg LW·day) from 23 days before conception to 122–123 days of gestation. The ewes were subjected to a feeding behaviour trial during 5 days after and adaption period of 14 days to eat alfalfa hay ad libitum and 300 g of rice bran. Eight days before the registration began animals were transferred to a roofed barn and located in individual pens with separated alfalfa and rice bran feeders, and a free-available water source. The feed preference was registered twice a day. Dry matter intake (DMI) was daily determined. Behaviour of each ewe was recorded every 10 min from 0800 to 1200 h, and from 1400 to 1800 h. The percentage of ewes that preferred to rice eat bran first was greater in LFA than HFA ewes (73% vs. 45%; P = 0.04). The alfalfa hay intake was greater in LFA than in HFA ewes (3078 vs. 2949 ± 0.61 g/day; P = 0.04) and in S than in T ewes (3126 vs. 2932 ± 61.0 g/day, P < 0.01). All ewes ate the total offered amount of rice bran (300 g/d each), thus DMI showed the same response that alfalfa intake previously described. The % of time eating alfalfa hay was greater for LFA than HFA (38.0 vs 29.2 ± 3.4; P < 0.01). These variables were not influenced by the interaction. The time spent eating and standing up, and time spent resting were affected by the interaction treatment × TB (P ≤ 0.05 in all cases) as T-LFA ewes spent more time eating (P = 0.02) and thus, standing up (P = 0.02), but less resting (P = 0.02) and with no apparent activity (P = 0.05) than T-HFA with no differences between LFA and HFA groups in the S ewes. In conclusion the maternal nutrient restriction affected the preference for feed, the ingestive behaviour and the welfare of aged female offspring.

Intake, Digestibility, Ruminal Fermentation, and In Situ Disappearance of Bermudagrass Hay by Lactating Beef Cows Offered Corn or Hominy Feed as Supplements at Two Different Rates.

Hominy feed (HF) has been evaluated in feedlot and dairy rations but has not been evaluated as a supplemental energy source for lactating beef cows. The objective of this study was to determine the effect of level of HF supplementation on intake, digestibility, ruminal fermentation characteristics, and in situ dry matter (DM) disappearance of bermudagrass hay. Five ruminally cannulated lactating beef cows (body weight (BW) = 596 kg, SE = 13.9) were used in an experiment with a 5 × 5 Latin square design. Treatments were a bermudagrass hay-basal diet with low HF (LH; 0.25% BW), medium HF (MH; 0.50% BW), low ground corn (LC; 0.25% BW), medium ground corn (MC; 0.50% BW) and no supplement (CON). Cows were housed individually, and supplements were offered at 0800 daily. Hay was offered to maintain 10% refusal. Periods were 16-d, with 10 d for adaptation. Ruminal fluid was sampled on d 14 of each period for measurement of pH, volatile fatty acids, and rumen ammonia-N. An in situ degradation experiment for bermudagrass hay was completed for each diet. Hay dry-matter intake (DMI % BW) was not affected (p = 0.14) by supplement, but total DMI (DMI % BW) was greater (p ≤ 0.05) in MH and MC compared to LH and CON. Digestible DMI % BW was greater (p = 0.05) in MH compared to LC, MC was intermediate, and LH and CON were lesser (p ≤ 0.01) than all other diets. Dry-matter fill, passage rate, and retention time did not differ by diet (p ≥ 0.31). A diet × time interaction was observed for ammonia-N (p = 0.0002), and propionate (p = 0.02) time effects were observed for other parameters, but no diet effects. Bermudagrass hay's potentially degradable fraction was greater (p ≤ 0.05) in LH than MH and CON, but effective DM degradability was not different (p = 0.39) among diets. Overall, no diets reduced hay intake or disappearance compared to CON; therefore, no negative associative effects were observed from any of the supplements at the levels offered in this study.

Substitution of soyabean meal by faba bean improves body weight, sperm production and testosterone concentration in mature Queue Fine de l'Ouest rams.

The current study aimed at investigating the effects of partial or total substitution of soybean meal with faba bean on reproductive parameters of Queue Fine de l'Ouest rams. Eighteen adult rams (49.8 ± 3.7 kg and 2.4 ± 1.5 years old) were divided into three homogenous groups. Rams received oat hay ad libitum and 3 types of concentrate (33 g/BW0.75) where soybean meal was the main protein source (SBM diet, n = 6), partially (50%, SBMFB diet, n = 6) or totally (100% FB diet, n = 6) substituted in nitrogen basis by local faba bean. The volume of ejaculate, sperm concentration and sperm mortality rate were measured weekly by collecting semen using an artificial vagina. Serial blood samples were collected 30 days and 120 days after the beginning of the experiment in order to assess plasma testosterone concentrations. The results showed that hay intake was affected (P < 0.05) by the nature of the nitrogen source incorporated (1032.3 ± 12.2; 1026.8 ± 56.6 and 972.8 ± 39.05 g DM/d for SBM, FB and SBMFB respectively. The average live weight of the rams increased from 49.8 ± 0.4 (week 1) to 57.3 ± 0.9 kg (week 17) without effect of the diet. A positive effect of faba bean incorporation in the concentrate was observed on ejaculate volume, concentration and spermatozoa production. All these parameters were significantly higher in SBMFB and FB groups than in SBM group (P < 0.05). The protein source did not affect the percentage of dead spermatozoa and the total abnormalities which were similar for the three diets (38.7; 35.8 and 38.1% for SBM; SBMFB and FB, respectively). The mean testosterone concentration was higher (P < 0.05) in rams fed with faba bean (1.7 ± 0.7 to 1.9 ± 0.7 ng/ml for the SBMFB and the FB groups respectively) than in rams fed SBM diet (1.06 ± 0.5 ng/ml). It was concluded that the substitution of soybean meal by faba bean improved the reproductive performance and did not affect sperm quality in Queue Fine de l'Ouest rams.

136 Relationship of Mature Beef Cows on an Unprocessed Hay Diet to Residual Intake and Greenhouse Gas Exchange During Gestation and Lactation

Abstract The objective of this study was to compare residual feed intake (RFI) and greenhouse gas exchange in mature beef cows during gestation and lactation when consuming an unprocessed, grass hay diet. Twenty-six mature Angus and Angus x Hereford cows (4.5 ± 0.0 yr) were used in two voluntary intake studies. Cows were evaluated during mid-gestation (GEST) and late lactation (LACT). Unprocessed grass hay (GEST = 8.73% CP and 59.25% TDN; LACT = 8.31% CP and 54.50% TDN) and a mineral mix were provided for ad libitum consumption. Individual animal feed intake data was collected for 52 d and 71 d for GEST and LACT respectively using SmartFeed intake units (C-Lock Inc., Rapid City, SD) and a stocking rate of 3 cows per feeder. An open-circuit, gas-quantification system (GreenFeed, C-Lock Inc., Rapid City, SD) was used to collect CH4 production for 9 days per pen for a minimum of 20 visits per cow. Hay intake averaged 13.8 ± 2.3 kg and 16.6 ± 2.0 kg during GEST and LACT, respectively. The Pearson correlation coefficient for hay intake among the two stages of production was 0.65 (P &amp;lt; 0.01). Metabolic body weight, average daily gain, and ultrasound ribeye area explained 46% of the variation in GEST DMI (P &amp;lt; 0.01), and milk yield, metabolic body weight, and average daily gain explained 64% of the variation in LACT DMI (P &amp;lt; 0.01). Each one kg additional milk production resulted in 0.7 kg greater hay intake during LACT (P &amp;lt; 0.01). There was a moderate correlation between GEST and LACT CH4 (r = 0.64) and a moderate correlation between CH4 production within each stage of production and DMI for that same stage of production (r = 0.58 and 0.63 for GEST and LACT, respectively). Hay intake was moderately correlated between stages of production although highly sensitive to milk yield.

137 Replacement Heifer Gain, Feed Intake and Efficiency While Consuming an Unprocessed Hay Diet Followed by a Mixed Concentrate/Forage Diet

Abstract The objective of this study was to evaluate weight gain, feed intake, and feed efficiency in beef heifers while consuming two diets divergent in energy density. Fifty-four yearling Angus and Angus cross heifers (initial body weight = 307.5 ± 30.35 kg) were subject to sequential intake trials using SmartFeed individual intake measuring technology (C-Lock Inc., Rapid City, SD) in drylot pens at the Oklahoma State University Range Cow Research Center. The first intake period (HAY) was initiated on July 15 (d -21) with a 21-d adaptation period and a 70-d intake period. Bermudagrass hay (10.3% CP, 2.0 Mcal ME, and 56% TDN) and a salt/mineral/vitamin supplement was offered on an ad libitum basis throughout the experiment. The second intake period was initiated on d-92 and included 14 d of adaption with 42 d of data collection. A mixed diet (12.4% CP, 45% NDF, and 65% TDN) consisting of 50% chopped bermudagrass hay, concentrate feeds, and a liquid supplement containing minerals and vitamins (TMR) was offered on an ad libitum basis. In both periods, weights were recorded every 14 days, and ADG was calculated by regressing body weight over time. Dry matter intake (DMI) and residual feed intake (RFI) were calculated at the end of each feeding period. Statistical regression equations were used to predict RFI for both HAY and TMR, including average metabolic body weight and average daily gain for each of their respective trials. For RFI, cattle were classified as inefficient, average, or efficient based on 0.5 SD away from the mean RFI score. Descriptive statistics for HAY evaluated traits of DMI, ADG, and RFI (means ± SD) were 5.49 ± 0.84 kg, 0.15 ± 0.16 kg, and 0.0 ± 1.01 kg, respectively. Means ± SD for DMI, ADG, and RFI for TMR were 9.54 ±1.26 kg, 1.45 ± 0.38 kg, and 0.0 ± 0.15 kg. Spearman rank correlations for DMI, ADG, and RFI were 0.35 (P = 0.0089), 0.16 (P = 0.2367), and 0.52 (P &amp;lt; 0.0001), respectively. This initial study suggests that intake of hay and a mixed diet may be modestly correlated, while there is no relationship of weight gain when consuming forage and weight gain consuming a mixed, processed diet.

62 Feeding steamed or soaked hay affects water intake and preference compared to dry hay

Stalled horses frequently experience respiratory disease. Soaking or steaming hay before feeding is a common strategy to reduce exposure to irritants. However, the effects of hay treatments on water intake and fecal dry matter (DM) are not well understood. We hypothesize that water intake is higher when feeding dry hay compared with feeding soaked or steamed hay and that fecal DM is related to water intake and DM intake. This study also evaluated preference for steamed, soaked, or dry hay when given a choice. Six mature horses (>3yr; 3 mares and 3 geldings, avg weight 558 kg, range 528–624) of mixed breeds were used. Horses were randomly assigned to either soaked, steamed, or dry hay for 5 d then treatments were rotated weekly with a 2 d washout between treatments. Hay (1.3% of BW, DM) was soaked for 30 min at room temperature or steamed (reaching 76°C by 90 min). Hay treatments were grab sampled weekly. Water intake and hay intake were measured gravimetrically each morning after horses were stalled overnight. Each morning, recently voided feces were collected from each horse. Hay and fecal samples were dried to a steady weight (24 h at 55°C) to determine DM. A preference study was conducted with the 6 adapted horses and 6 new horses. Horses were offered all 3 hay types simultaneously (1 kg each type for 1 h) and remaining hay was recorded. Data were analyzed using mixed model ANOVA with day as arepeated measure and treatment and day as main effects (SAS 9.4). There was a main effect of treatment on water intake (P = 0.0001). Horses fed dry hay drank more water compared with horses fed soaked hay (2.57 ± 0.290 and 1.10 ± 0.290 L/100 kg BW, respectively; P < 0.05). Moreover, DM intake was not influenced by hay treatment (P = 0.4463) but there was a change in DM intake over time (P = 0.0019). DM intake was the lowest on d 1 then increased by d 5 (0.96 ± 0.024 and 1.05 ± 0.034 kg/100 kg BW, respectively; P < 0.05). There was a positive relationship between DM and water intake (r = 0.2106; P = 0.0464) and a negative relationship between DM intake and fecal DM (r = −0.2395; P = 0.0230). The preference study revealed that non-adapted horses tended to consume more steamed hay compared with horses adapted to steamed hay (P = 0.0676), whereas horses adapted to treatments tended to consume more soaked hay compared with non-adapted horses (P = 0.0946). Overall, these results indicate that water is an important management consideration when feeding horses dry, steamed, or soaked hay. Moreover, when modifying hay types or treatments in a horse's diet, time for adaptation is necessary to ensure adequate intake to meet nutrition requirements.

Effect of kraft pulp inclusion in calf starter on performance, health, and plasma concentration of glucagon-like peptide 2 in calves

Kraft pulp (KP), an intermediate product obtained when wood chips are converted to paper, contains highly digestible fiber. This study evaluated the effect of KP inclusion in calf starters on growth performance, health, and plasma glucagon-like peptide 2 (GLP-2) concentration in calves. Twenty-five Holstein heifer calves were raised on a high plane of nutrition program using milk replacer containing 29% crude protein and 18% fat until 49 d after birth, and were fed calf starters containing KP at 0 (CON; n = 14) or 12% (KPS; n = 11) on a dry matter basis. All calves were fed the treatment calf starters and timothy hay ad libitum. Blood was collected at 4, 14, 21, 35, 49, 70, and 91 d after birth. Dry matter intake (DMI) of milk replacer and hay was not affected by treatment, whereas calf starter DMI was lower for KPS (0.93 kg/d) than for CON (1.03 kg/d). Higher neutral detergent fiber (NDF) content in KPS (31.7%) than in the CON starter (22.1%) resulted in higher NDF intake for KPS (0.55 kg/d) than for CON (0.47 kg/d). However, the consumption of starch was lower for KPS (0.29 kg/d) than for CON (0.33 kg/d). Despite the lower starter intake for KPS, body weight and average daily gain did not differ between treatments. No significant difference was observed in the plasma concentrations of metabolites, except for β-hydroxybutyrate (BHB); BHB concentration was lower for KPS (216 μmol/L) than for CON (257 μmol/L). The area under the curve for plasma GLP-2 concentration was higher for KPS (54.1 ng/mL × d) than for CON (36.0 ng/mL × d). Additionally, the fecal score postweaning (1.19 and 1.48 for KPS and CON, respectively) and the number of days that calves developed diarrhea throughout the experimental period (2.50 d and 8.10 d for KPS and CON, respectively) were lower for KPS than for CON. These results indicate that feeding KP reduces the severity and frequency of diarrhea without adversely affecting growth performance. This could be attributed to the increased plasma GLP-2 concentration induced by higher NDF intake.

Preweaning Nutrition and Its Effects on the Growth, Immune Competence and Metabolic Characteristics of the Dairy Calf

Feeding increased volumes of milk in the preweaning phase has been shown to improve growth, morbidity and mortality rates in calves (Bos Taurus). This experiment enlisted 20 Holstein-Friesian dairy replacement calves from birth until weaning (at 10 weeks of age) and assessed the effect of feeding either 4 L (Low) or 8 L (High) of milk per calf per day on their growth, immune competence and metabolic characteristics. The responsiveness of these systems was compared through a vaccination immune challenge. Calves in the High treatment group were significantly heavier from two weeks of age and were 19 kg heavier than calves in the Low treatment group at weaning. Calves in the High treatment group also exhibited greater immune responses, with significantly higher white cell counts and neutrophil counts than calves in the Low treatment group post-vaccination. Calves in the High treatment group also had lower beta-hydroxybutyrate both pre- and post-vaccination, and higher glucose and insulin levels post-vaccination, indicating superior metabolic characteristics. Calves had ad libitum access to lucerne hay (Medicago sativa) and a commercial concentrate. Solid feed intakes were mostly the same between treatments, with differences in hay intake only detected at 7 and 8 weeks of age. Results from this experiment are indicative of a positive influence of accelerated preweaning nutrition on growth, immune response and metabolic characteristics.

Twice daily feeding of canola oil steeped with Asparagopsis armata reduced methane emissions of lactating dairy cows

Red seaweeds have emerged as a potent methane-mitigating feed additive in ruminant diets. However, to date they have only been applied to production systems where total mixed rations (TMR) are given. New formulations are being developed to increase the application of red seaweeds, mainly Asparagopsis spp., across different production systems including those without TMR such as grazing-based systems. One product of interest is Asparagopsis armata steeped in edible oil (ASP-Oil) to extract and stabilise the primary antimethanogenic compound, bromoform. The aim of this study was to determine the effect of feeding two formulations of ASP-Oil, with (ASP-Oil 1) and without (ASP-Oil 2) the seaweed biomass removed, on enteric methane emissions, dry matter intake (DMI), milk yield and milk composition of dairy cows over 32 d. Thirty-nine lactating, multiparous, Holstein-Friesian (75 ± 20.6 days in milk) were randomly allocated to one of the three treatments; control (CON; basal diet + 134 g canola oil), ASP-Oil with the seaweed biomass removed (ASP1; basal diet + 134 g ASP-Oil 1), and ASP-Oil without the seaweed biomass removed (ASP2; basal diet + 145 g ASP-Oil 2 + 12 g canola oil). The treatments were given twice daily, using a pulse feeding technique, as a concentrate/oil supplement during each milking. The basal diet consisted of vetch hay ad libitum and 7.0 kg DM/d of a grain mix. Individual forage intakes were measured daily via electronic monitoring of individual cows at the feed bins. Methane emissions were measured using the modified sulphur hexafluoride tracer technique on days 27–32. At the rate of 136 g/d, there was no significant effect of treatment on DMI or milk yield, however during the transition period a rate of 268 g/d decreased hay intake. The supplementation of ASP1 and ASP2 decreased energy corrected milk (ECM; P = 0.029) compared to those cows offered the CON diet. Methane production (g/d) of cows given the ASP1 diet was 44 % lower than cows on the CON diet, methane yield (g/kg DMI) was 44 % lower, and methane intensity (g/kg ECM) was 38 % lower. For the ASP2 cows, the reductions were 39 % for methane production, 33 % for methane yield, and 31 % for methane intensity. Feeding the ASP-Oil increased bromoform concentrations in milk. However, the concentrations detected were demonstrated to be considerably lower than published safe concentrations in milk for human consumption (100 μg/L). These results show that the ASP-Oil has potential to be used as a methane mitigating feed additive when fed in a pulse feeding system.

Late gestational nutrient restriction in primiparous beef females: nutrient partitioning among the dam, fetus, and colostrum during gestation.

Fall-calving primiparous crossbred beef females [body weight (BW): 451 ± 28 (SD) kg; body condition score (BCS): 5.4 ± 0.7] were allocated by fetal sex and expected calving date to receive either 100% (control; CON; n = 13) or 70% (nutrient restricted; NR; n = 13) of metabolizable energy and metabolizable protein requirements for maintenance, pregnancy, and growth from day 160 of gestation to calving. Heifers were individually-fed chopped poor quality hay and supplemented to meet targeted nutritional planes based on estimated hay intakes. Dam BW, BCS, backfat, and metabolic status were determined pre-treatment, every 21 d (BW and metabolic status) or 42 d (BCS and backfat) during gestation, and post-calving. At birth, calf BW and size were measured, and total colostrum from the most full rear quarter was collected pre-suckling. Data were analyzed with nutritional plane, treatment initiation date, and calf sex (when P < 0.25) as fixed effects. Gestational metabolites included day and nutritional plane × day as repeated measures. During late gestation, CON dams gained (P < 0.01) maternal (non-gravid) BW and maintained (P ≥ 0.17) BCS and backfat, while NR dams lost (P < 0.01) maternal BW, BCS, and backfat. Circulating glucose, urea N, and triglycerides were less (P ≤ 0.05) in NR dams than CON at most late gestational timepoints after treatment initiation. Circulating non-esterified fatty acids were greater (P < 0.01) in NR dams than CON. Post-calving, NR dams weighed 63.6 kg less (P < 0.01) and were 2.0 BCS less (P < 0.01) than CON. At 1 h post-calving, NR dams had less (P = 0.01) plasma glucose and tended to have less (P = 0.08) plasma triglycerides than CON. Nutrient restriction did not affect (P ≥ 0.27) gestation length, calf birth weight, or calf size at birth. Colostrum yield was 40% less (P = 0.04) in NR dams than CON. Protein and immunoglobulin concentrations were greater (P ≤ 0.04), but free glucose and urea N concentrations were less (P ≤ 0.03), in colostrum of NR dams than CON. Colostrum total lactose, free glucose, and urea N were less (P ≤ 0.03) in NR dams than CON, but total protein, triglycerides, and immunoglobulins were not affected (P ≥ 0.55). In summary, beef heifers experiencing late gestational nutrient restriction prioritized partitioning nutrients to fetal growth and colostrum production over maternal growth. During undernutrition, fetal and colostral nutrient demands were largely compensated for by catabolism of maternal tissue stores.