Percentage Of BW Research Articles

Pulmonary lesions and clinical disease response to Mannheimia haemolytica challenge 10 days following administration of tildipirosin or tulathromycin1,2

This clinical trial evaluated the impact of metaphylactic antimicrobial administration 10 d before experimental inoculation with Mannheimia haemolytica (MH) to mitigate pulmonary lesions. Thirty-three crossbreed heifers were procured as a single group and were randomly allocated to 1 of 3 blocks and to treatment, tildipirosin (ZUP; 4 mg/kg) or tulathromycin (DRX; 2.5 mg/kg) or saline (SAL; 1 mL/45.5 kg), within block on arrival at Kansas State University. All trial procedures were staggered by 7-d intervals for each block, resulting in all animals within a block receiving treatment, challenge, and necropsy on the same dates. Heifers within each block received an endoscopic MH challenge 10 d following treatment administration (d 0) and were housed in individual indoor stalls for 3 d postchallenge. Clinical illness scores (CIS), respiration quality scores, appetite scores, and injection site reactions were recorded on all animals from d 0 through d 13. Rectal temperatures were measured once daily on all animals from d 8 through d 13. Heifers were necropsied, and lung lesions were evaluated on d 13. Lung lesion data were evaluated using nonparametric methods (Kruskall-Wallis), and standard least squares models were used to evaluate the remaining variables. The pulmonary lesion scores (percentage of affected lung) ranged from 3.3% to 39.8% for all heifers with 92% (11/12) of ZUP-treated heifers having <10% lesions. Tildipirosin-treated heifers had lower (P < 0.05) lung lesion scores when compared with DRX- and SAL-treated heifers. Lung weight expressed as a percentage of BW was lower (P < 0.05) in ZUP heifers compared to DRX- and SAL-treated heifers. The probability of receiving abnormal CIS, appetite scores, and respiratory scores was lower (P < 0.05) in ZUP-treated heifers compared to DRX- and SAL-treated animals. This study showed that heifers treated with tildipirosin 10 d before MH challenge have less pulmonary damage and fewer clinical signs of illness compared to heifers treated with DRX or SAL.

Effects of time of supplementation on cattle grazing annual ryegrass. III. Dry matter intake and digesta kinetics

ABSTRACT Grazing behavior of ruminants can be affected by different management practices, such as time of supplementation. Nutrient utilization for forage-fed cattle can be optimized through the timing of supplementing nutrients within a day. Time of day of supplementation on DMI and ruminal kinetics parameters of beef cattle grazing annual ryegrass and supplemented with corn gluten feed (CGF) was evaluated using 8 (2 per treatment) ruminally cannulated crossbred heifers (initial BW = 351 ± 22 kg). Treatments were 1) control, nonsupplemented; 2) morning (0700 h) supplementation with 0.5% of BW of CGF; 3) noon (1200 h) supplementation with 0.5% of BW of CGF; or 4) afternoon (1600 h) supplementation with 0.5% of BW of CGF. When DMI was expressed as percentage of BW, it was greater (P = 0.03) in noon-supplemented heifers compared with those supplemented at 0700 h. Noon-supplemented heifers also had greater (P > 0.05) fluid passage rate and flow rate when compared with heifers supplemented in the morning hours. Particulate passage rate was lower (P = 0.03) for the morning-supplemented treatment when compared with the afternoon-supplemented group. Transient time decreased (P = 0.02) for the control treatment, when compared with noon-supplemented heifers. These data suggest that time of supplementation with CGF affected DMI and digesta kinetics variables associated with those changes in DMI. The effect of treatment on fermentation parameters and digestibility of forage, supplement, and nutritional entities should be investigated.

Effects of temporary calf removal before fixed-time artificial insemination on pregnancy rates and subsequent calf performance in suckled beef cows1

Two experiments were conducted to determine the effect of calf removal (CR) on pregnancy rate (PR) and calf performance in suckled beef cows. Cows in both experiments were synchronized with the 7-d CO-Synch + CIDR protocol [i.e., 100-µg injection of GnRH at controlled internal drug release (CIDR) device insertion (d -7) with 25-mg injection of PGF2α at CIDR removal (d 0), followed by injection of GnRH and timed AI (TAI) on d 3]. Cows were blocked by location (6 locations), stratified by days postpartum (DPP) and parity, and assigned to 1 of 2 treatments in Exp. 1: 1) control (Control; n = 156); 2) calves were separated from their dams between d 0 and 3 (CR72; n = 168); and 1 of 4 treatments in Exp. 2: 1) Control (n = 103); 2) CR72 (n = 104); 3) calves were separated from their dams between d 0 and 2 (CR48A; n = 95); and 4) similar to CR48A but CR between d 1 and 3 (CR48B; n = 53). Transrectal ultrasonography of ovarian structures was performed on d 0, 1, 2, 3, 4, and 10 (in a subset of cows) to determine pregnancy status on d 33. Blood samples were collected on d -14, -7, 0, 3, and 10 (in a subset of cows) to determine concentrations of progesterone (P4) and estradiol (E2). Calves were blocked by age as young (25 to 59 d), medium (60 to 79 d), and old (≥80 d), and were weighed on d 0, 3, 33, and 63. Overall PR did not differ among treatments and averaged 50%. Follicle growth rate from d 0 to 3 tended (P = 0.06) to be greater for CR72 (0.42 ± 0.15 mm/d) compared with Control (0.02 ± 0.15 mm/d). Young (-3.9 ± 0.3%) and old (-3.1 ± 0.4%) calves lost a greater (P < 0.001) percent of BW (PBW) during CR than medium-age (-1.6 ± 0.3%) calves exposed to CR72. In Exp. 2, PR were similar among all 3 locations (49%; P = 0.15). Young (-4.8 ± 0.6%) and medium (-3.0 ± 0.5%) calves lost greater (P < 0.01) percent body weight (PBW) during CR than old (-1.4 ± 0.6%) calves within the CR72 treatment. Calves exposed to CR48 (-2.2 ± 0.6%, -1.1 ± 0.6%, and -2.4 ± 0.6% PBW change for young, medium, and old, respectively) lost more BW than calves in the Control group (-3.7 ± 0.4%, -1.7 ± 0.5%, and -2.1 ± 0.5% PBW change for young, medium, and old, respectively). Subsequent calf weights on d 33 and 63 were greater (P < 0.05) in Controls than cows exposed to CR48 or CR72 treatments. We conclude that CR stimulated follicle growth but failed to enhance PR to TAI. However, CR had a negative impact on subsequent calf performance, which differed, depending on the duration and age of the calf when exposed to CR.

Insoluble nonstarch polysaccharides in diets for weaned piglets

To examine the effect of inclusion insoluble nonstarch polysaccharides (iNSP) in weaned diets on postweaning piglet performance, intestinal activity, and microbial composition 2 experiments were designed. In Exp. 1, 180 piglets were weaned at 28 d of age and divided over 3 treatments: positive control (PC; highly digestible protein), negative control (NC; standard cereal-based diet), and an experimental diet {iNSP; standard + 15% iNSP [wheat straw and oat (Avena sativa) hull]}. Diets were fed during 14 d after weaning. The ADFI, ADG, and G:F were determined. The inclusion of iNSP increased (P < 0.001) ADFI and G:F during days 0 to 14 after weaning and increased the ADG (P = 0.008) during days 0 to 7 after weaning compared with the NC diet. In Exp. 2, 36 piglets were fed the same diets as in Exp. 1. On days 5 and 14 after weaning, 18 piglets were euthanized to determine enzyme activity, intestinal morphology, and microbial population in the ileum and colon and organ weight. The iNSP diet reduced the concentration of Escherichia coli bacteria in the ileum (P = 0.021) and in the colon (P = 0.002) digesta and tended to increase (P = 0.060) the amylase activity. The iNSP diet stimulated the physical adaptation of the gastrointestinal tract because stomach weight as percentage of BW was heavier (P = 0.004) than for the NC diet. In conclusion, the consumption of diets with higher iNSP content in the early weaning period affects the microbial colonization without reducing enzyme activity or animal performance compared with a standard weaned pig diet.

Feedlot performance, feed efficiency reranking, carcass traits, body composition, energy requirements, meat quality and calpain system activity in Nellore steers with low and high residual feed intake

The aim was to evaluate growth, carcass traits, feed efficiency reranking, body composition, calpain system activity and meat quality in Nellore steers that were phenotypically ranked for high and low residual feed intake (RFI). Seventy-two Nellore steers (16–21 month-old, 334±19kg BW) had free access to a feedlot diet for 70d (feeding period 1, P1). Daily dry matter intake (DMI), body weight gain (ADG) and ultrasound carcass traits were measured individually. The 12 lowest and the 12 highest RFI steers were classed as low- and high-RFI groups and were fed for a second feeding period (feeding period 2, P2). Spearman's rank correlation was performed for RFI and gain-to-feed ratio (G:F) measured over P1 and P2. The carcass traits, meat quality and calpain system activity were evaluated at slaughter, and body composition was determined. In P1, low-RFI steers had greater G:F (0.159 vs. 0.134; P<0.001), lower DMI (9.30 vs. 11.1kg/d; P<0.0001), lower RFI (−0.80 vs. 0.85kg/d; P<0.0001), and tended to have lower rates of rump fat gain (4.48 vs. 6.05mm; P=0.06), but no differences were observed for ADG, BW, and other traits measured by ultrasound (P>0.05). In P2, no differences between RFI classes were observed for G:F and DMI as a percentage of BW (P>0.05), and small differences were observed for DMI (8.25 vs. 8.99kg/d, P<0.05) and RFI (−0.28 vs. +0.29kg/d, P=0.06). The ranking correlations for RFI and G:F measured consecutively in P1 and P2 were low to moderate (r=0.11–0.40). Low-RFI steers had lower requirements of metabolizable energy (ME) for maintenance (131 vs. 160Mcal/kg EBW0.75d−1, P<0.05), but no differences were observed for fat and protein gain, retained energy and efficiency of ME use for gain (P>0.05). No differences between low- and high-RFI steers were observed for carcass traits at slaughter; however, low-RFI steers had 8.1kg less gastrointestinal fat than high-RFI steers. There were no RFI effects on meat shear force and the activities of μ-calpain, m-calpain and calpastatin (P>0.05). High-RFI steers had greater MFI in 1d aged LM (53.9 vs. 40.8, P<0.05). The variation in feed efficiency between high- and low-RFI Nellore steers is related to differences in energy requirements and deposition of fat on internal organs. The ranking for feed efficiency is altered as cattle become older. The selection for improved RFI in Nellore cattle may reduce feed requirements for beef production without affecting meat tenderness and enzymatic activity of the calpain system.

Effect of Cassava Hay and Rice Bran Oil Supplementation on Rumen Fermentation, Milk Yield and Milk Composition in Lactating Dairy Cows

Four crossbred (75% Holstein Friesian) lactating dairy cows, with an average live weight of 418±5 kg and 36±10 d in milk were randomly assigned according to a 2×2 factorial arrangement in a 4×4 Latin square design to evaluate the effects of cassava hay (CH) and rice bran oil (RBO) on feed intake, nutrient digestibility, ruminal fermentation, milk yield, and milk composition. Factor A was non-supplementation or supplementation with CH in the concentrate. Factor B was supplementation with RBO at 0% or 4% in the concentrate mixture. The four dietary treatments were (T1) control (Concentrate with non-CH plus 0% RBO; C), (T2) Concentrate with CH plus 0% RBO (CH), (T3) Concentrate with non-CH plus 4% RBO (RBO), and (T4) Concentrate with CH plus 4% RBO (CHRBO). The cows were offered concentrate, at a ratio of concentrate to milk production of 1:2, and urea-lime treated rice straw was fed ad libitum. Urea-lime treated rice straw involved 2.5 g urea and 2.5 g Ca(OH)2 (purchased as hydrated lime) in 100 ml water, the relevant volume of solution was sprayed onto a 100 g air-dry (91% DM) straw, and then covering the stack with a plastic sheet for a minimum of 10 d before feeding directly to animals. The CH based concentrate resulted in significantly higher roughage intake and total DM intake expressed as a percentage of BW (p<0.05). Ruminal pH, NH3-N, BUN and total VFA did not differ among treatments, while RBO supplementation increased propionate, but decreased acetate concentration (p<0.05). Furthermore, the population of total ruminal bacteria was significantly lower on the RBO diet (p<0.05). In contrast, the total ruminal bacteria and cellulolytic bacteria on the CH diet were higher than on the other treatments. Supplementation with CH increased (p<0.05) F. succinogens and R. flavefaciens populations, whereas the populations of B. fibrisolvens and M. elsdenii were increased on the RBO diet. In addition, supplementation with CH and RBO had no effect on milk production and composition in dairy cows, while fatty acid composition of milk was influenced by RBO supplementation, and resulted in significantly lower (p<0.05) concentrations of both short-chain and medium-chain FA, and increased (p<0.05) the proportion of long-chain FA in milk fat, as well as significantly increased cis-9, trans-11 CLA and total CLA. In conclusion, RBO or CH exhibited specific effects on DM, rumen fermentation, microbial population, milk yield and composition in lactating dairy cows, which were not interactions between CH and RBO in the diets. Feeding lactating dairy cows with RBO could improve fatty acid in milk fat by increasing cis-9, trans-11 CLA.

Bermudagrass intake and efficiency of utilization in Katahdin, Suffolk, and reciprocal-cross lambs

<h2>ABSTRACT</h2> Daily intake of fresh common bermudagrass was estimated using 12 spring-born Katahdin, Suffolk, and reciprocal-cross ewe lambs per year (n = 3 per breed group) individually fed fresh harvested forage in pens in each of 4 yr. Two 24-h estimates of intake were measured for each week of the study from June to August in each year. Intakes were expressed as both daily DM offered minus DM refused and daily as-fed forage offered minus as-fed forage refused. Efficiency of forage utilization was estimated similarly as kilograms of DMI per kilogram of gain and kilograms of as-fed intake per kilogram of gain for 3 yr of the experiment. Averaged over the 2 d per week and weeks of the study, DMI as a percent of BW averaged 2.92, 2.57, 3.05, and 2.60% in Katahdin, Katahdin × Suffolk, Suffolk × Katahdin, and Suffolk, respectively (sire breed listed first). Intake was highest in the Suffolk × Katahdin and Katahdin ewe lambs (P < 0.05) compared with Katahdin × Suffolk and Suffolk lambs. There was little evidence for direct heterosis or direct breed effects for DMI as a percentage of BW, but there was evidence of maternal breed effects in favor of Katahdin ewes (0.48 kg/kg of BW, P < 0.01). Efficiency of forage utilization averaged 0.110, 0.094, 0.112, and 0.092 kg of ADG per kilogram of daily DMI for Katahdin, Katahdin × Suffolk, Suffolk × Katahdin, and Suffolk, respectively. There was a trend for efficiency to be more favorable in lambs from Katahdin ewes compared with lambs from Suffolk ewes averaged over sire breed (P < 0.07, data not shown). These results indicate that genetic effects associated with breed can play an important role in regulating intake and efficiency in grazing animals and that breed composition should be considered in the design of efficient grazing systems.

Effect of rice bran oil supplementation on rumen fermentation, milk yield and milk composition in lactating dairy cows

The objective of this study was to determine effects of rice bran oil (RBO) on feed intake, nutrient digestibility, ruminal fermentation, milk yield, and milk composition in lactating dairy cows fed at 0, 2, 4, and 6% in concentrate. Four crossbred (75% Holstein Friesian) lactating dairy cows with an average live weight of 399±59kg and 64±10days in milk were randomly assigned according to a 4×4 Latin square design. Cows were fed with total mixed ration (TMR), with a concentrate/roughage ratio of 60:40 and urea treated rice straw (5% urea) was used as a roughage source. Cows fed supplemental RBO were linearly decreased in feed intake expressed as kg/d and a percentage of BW. Increased level of RBO in concentrate linearly decreased digestibility of DM, OM, NDF and OM intake, but did not affect those of CP and ADF; however DMI and nutrient digestibility could maintain at 4% RBO supplementation as compared with control (0% RBO). RBO supplementation tended to increased in propionate concentration, which was highest in 4% RBO. Moreover, supplementing RBO linearly decreased in acetate concentration which resulted in a linearly decreased C2:C3 ratio and CH4 production. Although supplementing with RBO had not affected on milk yield and milk composition, while milk fat yield and milk protein yield (kg/d) were linearly decreased. 3.5% FCM and milk fat tended to decrease when increasing level of RBO in the diet. In addition, increased RBO supplementation linearly decreased concentrations of both short- and medium-chain FA, and linearly increased the proportion of long-chain FA in milk fat and cis-9, trans-11 CLA, as well as tended to be increased in total CLA, which was highest in cow fed with 4%RBO. In conclusion, RBO can be used as a good source of additional energy for lactating dairy cows; however adding high level of RBO might have adverse effect on DMI and nutrient digestibility. Based on this study, feeding dairy cow with RBO should not exceed 4% in concentrate to obtain the most beneficial effect on nutrient utilization, rumen fermentation and dairy cow performance.

Níveis de suplemento para novilhos Nelore terminados a pasto na seca: consumo e digestibilidade

The supplementation allows the supply of limiting nutrients and increase in efficiency of pasture utilization. The intake of supplement can be controlled by use of urea and mineral salt, avoiding dominancy of some animals over the others. The objective of this study was to evaluate the intake and apparent digestibility of nutrients in finishing phase Nellore steers fed different levels of supplements based on corn meal, during the dry season. The experiment was implanted on pasture of Panicum maximum Tanzânia, in four paddocks of 1.0 hectare. Four 30 months old and initial weight of 440 kg Nellore steers were used. The animals were distributed in 4x4 Latin square (four levels of supplementation and four periods). Levels of supplements use were: 1.0, 2.0, and 4.0 kg/animal/day, in addition to a control group receiving mineral mixture. The supplements, except the control, presented decreasing levels of crude protein (52.0 to 42.6% of dry matter) and proportions of mineral mixture:urea:corn meal of 10:10:80, 5:5:90 and 2.5:2.5:95, respectively. Urea was used as supplement intake controller. The experimental periods lasted 16 days each one, in a total of 64 days. The intake and the digestibility were measured with the use of the external indicator chromium oxide and internal indicator iADF. There was increasing linear effect for dry matter intake in kg/animal/day and percentage of BW, and intakes of crude protein, ethereal extract, neutral detergent fiber, non fibrous carbohydrates and total digestible nutrients, and there was no effect on the forage intake. There was increasing linear effect for the digestibility coefficient of dry matter and neutral detergent fiber. There was no effect for the digestibility coefficient of crude protein, ethereal extract and non fibrous car-bohydrates.

Gene expression in the arcuate nucleus of heifers is affected by controlled intake of high- and low-concentrate diets1

It was hypothesized that a high-concentrate diet fed during early calfhood alters the expression of genes within the arcuate nucleus that subserve reproductive competence. Beef heifers (n = 12) were weaned at approximately 3 mo of age, and after acclimation, were allocated randomly to 1 of 2 nutritional groups: 1) High Concentrate/High Gain (HC/HG), a high concentrate diet fed to promote a gain of 0.91 kg/d; or 2) High Forage/Low Gain (HF/LG), a forage-based diet fed to promote a gain of 0.45 kg/d. Experimental diets were fed under controlled intake for 91 d. At the end of 91 d, heifers were slaughtered by humane procedures, blood samples were collected, brains were removed, liver weights were determined, and rumen fluid was collected for VFA analyses. Tissue blocks containing the hypothalamus were dissected from the brains, frozen, and cut using a cryostat, and frozen sections were mounted on slides. Tissue from the arcuate nucleus (ARC) was dissected from sections for mRNA extraction. Microarray analysis was used to assess genome-wide transcription in the ARC using a 60-mer oligonucleotide 44K bovine expression array. The ADG was greater (P < 0.001) in heifers fed the HC/HG diet than in heifers fed the HF/LG diet. At slaughter, mean propionate to acetate ratios in the ruminal fluid and liver weight as a percentage of BW were increased (P < 0.005) in HC/HG compared with HF/LG heifers. Mean serum concentrations of insulin (P < 0.05) and IGF-1 (P < 0.005) were greater, and leptin tended to be greater (P = 0.1) in HC/HG heifers compared with HF/LG heifers. Approximately 345 genes were observed to be differentially expressed in the HC/HG group with approximately two-thirds of the genes exhibiting increased expression in the HC/HG group. Genes exhibiting decreased expression in the HC/HG group included agouti-related protein and neuropeptide Y, products of which are known to regulate feed intake and energy expenditure. Functional annotation of enriched Gene Ontology terms indicates that a number of biological processes within the hypothalamus are affected by consumption of high-concentrate diets, including those related to control of feed intake, regulation of cellular metabolic processes, receptor and intracellular signaling, and neuronal communication. In summary, dietary treatments shown previously to accelerate the timing of pubertal onset in heifers increased ruminal propionate, promoted enhanced metabolic hormone secretion, and altered gene expression in the ARC.

The Effects of Detraining on Muscle Mitochondria and Performance in Mice

Periods of training cessation (i.e. detraining), commonly occur during illness, injury, or travel. While it is well established that detraining can lead to a decline in mitochondrial capacity and subsequent endurance performance little is know about the timing of these events in mice. PURPOSE: The purpose of this study was to determine the effects of various periods of detraining on the decline in mitochondrial and performance related training adaptations in mice. METHODS: Male CD-1 mice were randomly assigned to either an untrained (UT) control group or a detraining time-point (0wks, 2wks, or 4wks). Prior to beginning the assigned detraining period, all mice completed 8wks of treadmill running (6 d/wk, 1hr/d at 25m/min and 5% grade). At each detraining time point mice performed a treadmill run to fatigue (RTF) test at 25m/min and 5% grade. Fatigue was recorded as the time at which the mouse could no longer keep pace with the treadmill despite one minute of continuous hand prodding. Additional mice were sacrificed at each detraining time point and the soleus (sol) muscle, and heart was harvested. Heart and body weight ((HW), (BW)) was measured and the sol was analyzed for gene expression (mRNA) of PGC-1alpha and mitochondrial DNA (mtDNA) using RT-PCR. Data was analyzed using a one-way ANOVA with significance set at P<0.05. RESULTS: HW expressed as a percentage of BW, was significantly greater at the end of training (0 wks) and at 2 wks and 4 wks of detraining, compared with UT mice (P<0.05). At 0 wk mice ran significantly longer than UT mice in the RTF test (P<0.05), however these training effects were lost following 2wks and 4wks of detraining. Expression of PGC-1alpha and mtDNA in the sol was elevated at 0wks and 2wks of detraining and had declined to UT values by 4wks. CONCLUSIONS: These results show that training cessation causes a rapid decline in mitochondrial related training adaptations in mice that is associated with decreased endurance performance. These findings illuminate the need for determining strategies, either nutritionally or physically, to prevent these effects during unavoidable breaks in training. Supported by a Student grant from ACSM.

Relationships between chewing behavior, digestibility, and digesta passage kinetics in steers fed oat hay at restricted and ad libitum intakes1

The objective of this study was to evaluate the relationships between chewing behavior, digestibility, and digesta passage kinetics in steers fed oat hay at restricted and ad libitum intakes. Four Hereford steers, with an initial average BW of 136 kg, were used in an experiment conducted as a balanced 4 × 4 Latin square with 4 treatments (levels of intake) and 4 periods. Animals were fed lopsided oat hay (Avena strigosa Schreb.) at 4 levels of intake (as a percentage of BW): 1.5, 2.0, 2.5, and ad libitum. Digestibility, chewing behavior, and digesta passage kinetic measurements were recorded during the experimental period. Chewing rates during eating and ruminating [(chews•min(-1))/g of DMI•kg(-1) of BW•d(-1)] decreased (P = 0.018 and P = 0.032, respectively) with increased DMI (g•kg(-1) of BW•d(-1)), whereas total chewing and total time spent on each chewing activity increased. Calculated total energy expended by the chewing activity was 4.2, 4.4, 5.2, and 5.3% of ME intake for DMI of 1.5, 2.0, and 2.5% of BW and ad libitum, respectively, indicating that adjustments in animal chewing behavior may be a mechanism of reducing energy expenditure when forages are fed at restricted intake. Hay digestibility decreased (P < 0.001) with increased DMI (r = -0.865). Digesta mean retention time (h) was strongly correlated with DMI (r = -0.868) and OM digestibility (r = 0.844). At reduced intake, hay digestibility was enhanced (P < 0.001) by extending digesta retention time and by increasing chewing efficiency, highlighting the relationship between chewing behavior and the digestive process. Fractional outflow rate of particulate matter from the reticulorumen (k(1)) was positively correlated with total chews, emphasizing that the decrease in particle size caused by chewing facilitates particle flow through the digestive tract. Increased hay intake also increased (P < 0.001) k(1), whereas passage rate of the liquid phase, transit time, and rumen fill were not affected (P > 0.05). The latter was correlated with rumen volume (r = 0.803). In conclusion, the results of this study indicate that animals fed at restricted intake increased chewing rate when eating and ruminating, which, along with a longer digesta retention time, contributed to enhance feed digestibility.

Prepartum dietary management of energy intake affects postpartum intake and lactation performance by primiparous and multiparous Holstein cows

An experiment was conducted to determine the effect of plane of energy intake prepartum on postpartum performance. Primiparous (n=24) and multiparous (n=23) Holsteins were randomly assigned by expected date of parturition to 1 of 3 prepartum energy intakes. A moderate energy diet [1.63 Mcal of net energy for lactation (NEL)/kg; 15% crude protein (CP)] was fed for either ad libitum intake (OVR) or restricted intake (RES) to supply 150 or 80% of National Research Council (2001) energy requirement, respectively, for dry cows in late gestation. To limit energy intake to 100% of NRC requirement at ad libitum dry matter intake (DMI), chopped wheat straw was included as 31.8% of dry matter (DM) in a control diet (CON; 1.21 Mcal of NEL/kg of DM; 14% CP). Multiparous and primiparous cows assigned to OVR gained body condition during the dry period [initial body condition score (BCS)=3.3], but were not overconditioned by parturition (BCS=3.5). Multiparous cows in the OVR group lost more BCS postpartum than multiparous RES or CON cows. Primiparous cows lost similar amounts of BCS among dietary treatment groups postpartum. Addition of chopped wheat straw to CON diets prevented a large decrease in DMI prepartum in both primiparous and multiparous cows. During the first 3 wk postpartum, DMI as a percentage of BW was lower for multiparous OVR cows than for multiparous RES cows. Prepartum diet effects did not carry over through the entire 8-wk lactation period. Because of greater mobilization of body stores, OVR cows had greater milk fat percentage and greater 3.5% fat-corrected milk yield during the first 3 wk postpartum. Multiparous cows assigned to OVR experienced a 55% decrease in energy balance and primiparous cows a 40% decrease in energy balance during the last 3 wk before parturition, compared with CON or RES cows that had little change. Multiparous cows fed OVR had a greater contribution of energy from body energy reserves to milk energy output than either CON or RES cows. Overfeeding energy prepartum resulted in large changes in periparturient energy balance. Even in the absence of overconditioning, a large change in DMI and energy balance prepartum influenced postpartum DMI and BCS loss, especially for multiparous cows. Chopped wheat straw was effective at controlling energy intake prepartum, although primiparous cows did not achieve predicted DMI. Even so, controlling or restricting energy intake in primiparous cows was not detrimental to lactational performance over the first 8 wk of lactation.

Effects of twin pregnancy and dry period feeding strategy on milk production, energy balance, and metabolic profiles in dairy cows1

The present study evaluated the interaction of pregnancy type [PT; single (S) vs. twin (T)] and dry period feeding management [D; close-up (CU) diet (NE(l) = 1.54 Mcal/kg of DM)] throughout the entire dry period (8W) vs. far-off (FO) diet (NE(l) = 1.32 Mcal/kg of DM) from 60 to 21 d before expected calving date (ECD) followed by CU diet until calving (3W). Treatments were arranged in a 2 x 2 factorial with a randomized block design with primiparous (n = 8) and multiparous (n = 39) Holstein cows. We hypothesized that increasing the duration of feeding a CU diet would improve metabolic status and lactation performance for cows with T, but not for cows with S. All cows were fed similarly in late lactation (90 to 60 d before ECD; diet NE(l) = 1.58 Mcal/kg of DM) and in early lactation (calving to 105 DIM; diet NE(l) = 1.71 Mcal/kg of DM). Prepartum DMI as percentage of BW did not differ (P > 0.10) with D but tended to be greater (P = 0.10) for cows with S than with T. Cows with T tended to have greater (P = 0.08) BW than cows with S, but conceptus-free BW was less (P = 0.001) for cows with T than for cows with S. No differences (P > 0.10) were detected in prepartum BCS or BCS change with PT or D. Energy balance (EB) was greater for cows with S than with T (P < 0.001) and for cows fed 8W vs. 3W (P = 0.01). Cows with T had greater (P < 0.001) NEFA and a tendency for greater liver triglycerides (TG; P = 0.07) and plasma beta-hydroxybutyrate (BHBA; P = 0.06) than cows with S. Prepartum cows fed 3W had greater (P = 0.01) liver TG and greater (P = 0.02) plasma NEFA, but less (P = 0.02) plasma BHBA than cows fed 8W. Plasma glucose (P < 0.004) and liver glycogen (P = 0.02) were less for cows with T but were not affected (P > 0.10) by D. Postpartum, there was no effect (P > 0.1) of PT or D on mean DMI as percentage of BW, BW, and BCS, but there was an interaction (P = 0.02) of PT x D for mean BCS. Cows that calved T were in a more positive (P = 0.004) EB than cows that calved S. Milk production was 5.2 kg/d greater (P = 0.04) for cows fed 8W; however, they were in less (P = 0.01) EB than cows that received 3W. Postpartum cows that calved T had decreased concentrations of plasma NEFA (P = 0.02) and liver TG (P = 0.04) but greater concentrations of plasma glucose (P = 0.03) than cows that calved S. Plasma BHBA (P = 0.07) and NEFA tended (P = 0.06) to be greater for cows that received 8W than 3W. Neither PT nor D affected (P > 0.1) plasma glucose and liver glycogen. There was a tendency for an interaction of PT x D for plasma NEFA and liver TG. In contrast to our hypothesis, response to D was independent of PT. Based on milk production data from the present experiment, 8W is a more desirable feeding strategy than 3W.

Effect of wheat forage maturity and preservation method on forage chemical composition and performance of growing calves fed mixed diets12

Three 2.4-ha wheat (Triticum aestivum L.) fields were used to test the effects of maturity at harvest (boot vs. dough) and preservation method (hay vs. silage) on forage yield, chemical composition, and animal performance when fed in mixed diets. Forages were incorporated into 4 diets in a 2 x 2 factorial arrangement of treatments with hominy feed, soybean hulls, and cottonseed meal as the primary concentrate ingredients. In Exp. 1 diets contained 20% wheat forage (DM basis) and were fed to 96 beef calves (n = 48 steers and 48 heifers; initial BW 229 +/- 6.0 kg) in 12 mixed-sex pens. In Exp. 2 diets contained 40% wheat forage (DM basis) and were fed to beef steers (n = 48; initial BW 198 +/- 6.8 kg) in 12 pens. These diets were also individually fed to 32 calves (Exp. 1, n = 16, BW = 187 +/- 9.4 kg; Exp. 2, n = 16 calves, BW = 160 +/- 8.2 kg) to determine DM and NDF digestibility and gastrointestinal tract passage kinetics. Advanced maturity increased (P < 0.01) DM yield, decreased (P < 0.01) CP concentrations, and tended (P = 0.10) to increase nonfiber carbohydrate concentrations, but did not affect (P >or= 0.22) NDF, ADF, or TDN concentrations. Maturity at harvest, preservation method, or their interaction did not affect (P >or= 0.15) ADG when wheat forage was fed as 20 or 40% of the diet. When calves were fed the 40% wheat forage diets, maturity at harvest did not affect (P >or= 0.27) DMI or G:F. Calves fed 40% hay diets consumed more (P = 0.04) feed DM as a percentage of BW than calves fed silage diets, but tended (P = 0.09) to be less efficient. With 20 or 40% wheat forage diets, there were no differences (P >or= 0.13) in passage rate, ruminal retention time, or fecal output due to maturity or preservation method. Digestibility of DM tended (P = 0.07) to be greater for silage than hay diets when fed in 20% wheat forage diets. Dry matter and NDF digestibility of 40% boot-stage wheat forage diets were greater (P < 0.01) than diets containing forage harvested in dough stage. Forty percent hay diets also tended (P = 0.07) to have greater DM digestibility, and NDF digestibility was greater (P < 0.01) compared with silage diets. Although differences in performance were not noted in the present experiments, increased maturity at harvest and preservation as silage can cause differences in DMI and digestibility of DM and NDF in diets containing 40% wheat forage.

Intake, Digestibility, Body Weight and Carcass Characteristics of Tigray Sheep Fed Tef Straw Supplemented with Sesame Seed Meal or Wheat Bran and their Mixtures

The study was conducted over 90 days feeding and 7 days digestibility trials at Enda Selassie ATVET College to assess the effect of supplementation on feed utilization and carcass characteristics in tef (Eragrostis tef) straw based feeding of Tigray rams. The rams were arranged in a randomized complete block design divided into five blocks based on initial BW. The treatments comprised of ad libitum tef straw (control, T1) and daily supplementation with 300 g dry matter (DM) sole sesame (Sesame indicum) seed meal (SSM, T2), 0.65SSM:0.35 wheat bran (WB, T3), 0.35SSM:0.65WB (T4) and sole WB (T5). Tef straw used in the study contained low (30.6 g kg -1 DM) crude protein (CP) and high (825.8 g kg -1 DM) neutral detergent fiber (NDF) contrary to the supplement feeds. Total daily DM intake and DM intake as a percentage of BW were higher (P T3 > T4 > T5 > T1. Daily BW gain was negative and lower (P ones (50-71.1 g day-1). Out of all supplemented treatments, T5 was lower (P was higher (P Keywords: Tigray Sheep; Body Weight; Carcass; Intake; Sesame Seed Meal; Tef Straw; Wheat Bran

Use of yeast cell walls; β-1, 3/1, 6-glucans; and mannoproteins in broiler chicken diets

Two experiments were carried out to evaluate the effect of dietary addition of yeast cell wall (YCW); β-1, 3/1, 6-glucan (BG); and mannoprotein complex (MP) purified fractions in broilers. In experiment 1, there was a control diet and 5 experimental diets containing, respectively: 10 mg of avilamycin (AVI)/kg of feed, 500 mg of YCW/kg of feed, 95 mg of MP/kg of feed, 145 mg of BG/kg of feed, and 95 mg of MP plus 145 mg of BG/kg of feed. All birds were vaccinated via drinking water against Newcastle disease virus at 9 d of age. At 42 d, chickens fed AVI, YCW, MP + BG, and BG diets had similar BW not significantly different from chickens fed the control diet. The antibody response of Newcastle disease virus vaccine was not affected by any experimental treatment. Broilers fed MP + BG diet had greater thymus weights (P ≤ 0.05), as a percentage of BW than those from the control and AVI treatments, but similar with respect to YCW and BG treatments. In experiment 2, there was a group-fed basal diet and 3 additional experimental groups receiving the basal diet supplemented with, respectively: 500 mg of YCW/kg of feed, 190 mg of MP/kg of feed, and 227 mg of BG/kg of feed. At 42 d of age, no difference in broiler growth rates was observed. Samples of the jejunum were collected at 21 d of age to determine villus height. Significantly higher villus height was observed in YCW, MP, and BG groups compared with that of the control group. The relative percentage of liver weight (P ≤ 0.01) was lower in broilers fed YCW than in broilers fed the control diet, but no differences were observed in respect to chickens fed BG. Data of these studies suggested that the changes in thymus and liver relative weights and villus morphology of broilers were induced with the same intensity by the use of complete YCW, MP + BG, and BG supplements.

The Substitution of Corn with Soybean Hulls and Subsequent Impact on Digestibility of a Forage-Based Diet Offered to Beef Cattle

To better understand the impact of corn and soybean hull supplementation on bermudagrass hay utilization, a digestion trial was conducted using 6 ruminally cannulated steers receiving bermudagrass hay supplemented with soybean hulls (HULLS), cracked corn (CORN), or soybean hulls and cracked corn (MIX; 75% and 25%, respectively) in a 3 × 3 Latin rectangle arrangement. Total DMI was not different among treatments as measured by kilograms per day (P = 0.06; from 6.52 to 7.48 kg/d) and percentage of BW per day (P = 0.67; from 2.41 to 2.79% BW/d). Similarly, hay DMI did not differ but tended to decrease (P = 0.06) among steers receiving HULLS (2.88 kg/d; 1.08% BW/d). Apparent NDF, ADF, and hemicellulose digestibilities were greatest (P < 0.001) among steers consuming HULLS (64.92, 65.39, and 64.01%, respectively) or MIX (62.66, 63.21, and 61.78%, respectively). Total ruminal VFA production was not different (P = 0.97) among treatments (232.6 to 289.7mM); likewise, ruminal pH did not differ (P = 0.31; 6.8 to 6.0). Acetate-to-propionate ratios did not differ (P = 0.46; 3.7 to 4.7), whereas NH3-N concentrations were greater (P = 0.05) among steers consuming HULLS and decreased for all diets 4 to 8h post-feeding. Data seem to indicate that replacing a portion of corn with soybean hulls may successfully improve fiber digestion and improve ruminal N utilization.

Evaluation of the National Research Council (1996) dry matter intake prediction equations and relationships between intake and performance by feedlot cattle1

Intake prediction equations of NRC based on initial BW and dietary NE(m) concentration were evaluated with a commercial feedlot database consisting of 3,363 pen means collected from 3 feedlots over a 4-yr period. The DMI predicted by NRC equations had significant (P < 0.01) mean and linear biases across the range of observed DMI in the database. In general, DMI was overpredicted by the NRC equations. Adjustment of the NE(m)-based prediction by use of a 12% increase in NE(m) concentration and a 4% decrease in predicted DMI associated with the feeding of monensin decreased bias. Dry matter intake predicted by the NE(m)-based monensin-adjusted, NE(m)- based, and initial BW equations explained 67, 66, and 64% of the variation in observed DMI, respectively. Relationships between ADG and G:F with DMI as a percentage of BW and NE(g) intake also were examined in the same data set. Across the wide range of average shrunk BW in the database (334.4 to 548.0 kg), ADG was positively related to DMI as a percentage of BW (P < 0.01); however, this relationship was not strong (r(2) = 0.17). Likewise, G:F showed little relationship with DMI as a percentage of BW (P < 0.01; r(2) = 0.05). By accounting for differences in maintenance energy requirements of pens with varying average BW, NE(g) intake was strongly and positively related to ADG (linear and quadratic, P < 0.01; R(2) = 0.70); however, G:F showed little relationship with NE(g) intake (P = 0.02; r(2) = 0.01). Our evaluations with measurements of DMI by cattle in commercial feedlots indicated the shortcomings of current published equations for predicting DMI and suggest the need for development of new equations with improved accuracy and precision. Furthermore, our data indicate that increasing NE(g) in- take increased ADG in a quadratic manner but did not affect G:F by pens of cattle in feedlots. These findings suggest a diminishing returns effect of energy intake on energy retention.

Effect of oleic acid–beeswax mixtures on mechanical, optical and water barrier properties of soy protein isolate based films

Soy protein isolate (SPI) based films are effective barriers to oxygen, lipids and aroma compounds but they provide yellowish films and are not effective water vapour barriers. Different ratios of lipid mixtures (oleic acid and beeswax at different ratios) were incorporated into the SPI based films to improve their properties. Oleic acid, pure or mixed with beeswax, had a plasticizing effect on the films and also reduced water vapour permeability regardless of the lipid ratio and the BW percentage in the lipid mixture. When the protein–lipid ratio was 1:0.25 and beeswax percentage in the lipid mixture ranged between 30 and 50, gloss values were the closest to those of the control film made with only SPI, and are consequently the most highly recommended, although they maintain yellowness.