Protein Source and Intake Effects on Diet Digestibility and N Excretion in Horses—A Risk of Environmental N Load of Horses

Six Finnhorse mares were used in a digestibility trial, in which six typical horse diets were compared. The diets were: (A) haylage 100%; (B) hay 100%; (C) hay 70% and oats 30%; (D) hay 70% and soybean meal + oats 30%; (E) hay 70%, rapeseed meal + oats 30% and (F) hay 70 %, linseed meal + oats 30%. The trial was conducted according to an unbalanced 6 × 4 Latin square design with four 3-week experimental periods. The experimental period consisted of 17-day preliminary feeding which was followed by a 4-day total faecal and urine collection periods to evaluate N excretion. The digestibilities of DM (p < 0.001) and OM (p < 0.001) in the haylage-only diet were lower compared to the other diets. The supplemental protein feeds improved the diet digestibility of CP (p = 0.002) compared to a hay + oats diet. Furthermore, the DM (p = 0.019), OM (p = 0.006), and CP (p = 0.016) digestibilities of the soya-supplemented diet were better than those of the rapeseed- and linseed-supplemented diets. Faecal excretion was greater for haylage (19.3 kg fresh faeces and 3.6 kg DM/day) and hay (18.7 kg fresh faeces and 3.6 kg DM/day) diets (p < 0.001) compared with the other diets. Urine excretion was also greater for forage-only diets compared with diets including protein supplements. Horses excreted 14.0 L urine/day on haylage-only diet (p = 0.026) and 14.3 L/day on a hay-only diet (p = 0.003). Horses excreted more nitrogen in their urine than in dung. N excretion differed between the diets. Horses on a haylage-only diet excreted 51.6 g N in faeces /day and on hay-only diet 51.4 g N/day. On the other hand, when protein content in forages increased, N excretion via urine increased (haylage vs. dried hay). Horses excreted less N in urine with hay-only diet than with haylage-only or protein-supplemented diets (p < 0.001). When N excreted in faeces and urine was counted together, horses excreted less N with a hay-only diet (p < 0.001) than with a supplemented one (oats and/or protein feeds). The results showed that feed choices affected the amount of nitrogen excreted. Feeding recommendations should consider not only the horse category and work level, but also the protein source. When good quality protein is fed, smaller N intakes can be applied to reduce the N excretion via urine and dung. At the farm level, improved understanding of feed quality, as well as feeding planning and practices, is a way to decrease the risk of N leaching and evaporation.

157 Effects of Monensin and Protein Type on Performance of Yearling Steers Grazing Smooth Brome

A two-yr study was conducted to evaluate the effects of monensin on sparing ruminal degradable protein in yearling steers grazing smooth bromegrass pastures (n = 288, initial BW = 332 kg, SD = 7). Treatment design was a 2 x 3 factorial with the following factors: 1) 0 or 200 mg monensin/steer daily; 2) no protein supplement, 1.25 kg soybean meal (SBM) as a source of RDP, or 1.31 kg non-enzymatically browned SBM as a source of RUP. Steers receiving supplemental protein were provided isonitrogenous amounts equivalent to dried distillers grains plus solubles at 0.50% BW. Steers were weighed approximately every 34 d to adjusted the amount of protein supplement. There was no interaction (P &gt; 0.41) of monensin by protein type for average daily gain (ADG). Rate of gain for steers supplemented monensin was not different (P = 0.26) from steers not supplemented monensin. However, monensin supplemented steers numerically gained 7.9% more than steers not provided monensin when no supplemental protein was provided. Compared to steers supplemented with no protein, supplementing RDP increased ADG by 0.19 kg/steer (P &lt; 0.001). Likewise, RUP supplementation increased ADG by 0.24 kg/steer (P &lt; 0.001) compared to steers supplemented no protein. Supplementing RUP increased ADG by 0.05 kg/steer (P &lt; 0.001) compared to steers supplemented RDP. Supplementing protein, especially rumen undegradable protein, improved yearling steer rate of gain on smooth bromegrass pastures. Monensin supplementation did not improve rate of gain. These data do not support the protein-sparing effects of monensin for steers supplemented with RDP.

Shrimp waste meal supplementation of cassava products based diet fed to broiler chickens

With the objective of investigating shrimp waste (SWM) and cassava leaf (CLM) meals as cheap alternatives and protein source mixtures that would best complement cassava root-soybean ration in total replacement for maize in broiler diets, six iso-energetic and iso-nitrogenous diets were evaluated using two weeks old Anak broilers in a growth and digestibility trial lasting seven weeks. Diet I was a maize-soybean based control diet while diets 2 to 6 contained whole cassava root meal (WCRM) in total replacement for maize, energy for energy. Diet 2 had soybean meal (SBM) as a major source of protein taking the protein supplied by SBM in diet 2 as 100%, SBM, CLM and SWM were combined thus in diets 3/0.5SBM: 0.5SIM), 4 (0.5SBM: 0.25SWM: 0.25CLAI), 5(0.25 SBM: 0.5SWM: 0.25CLM) and 6(0.5 SWM: 0.5 CL11). Average daily feed intake, weight gain (P< 0.01) and efficiency of feed conversion (P<0.05) were significantly influenced by dietary treatments. Results indicate that replacing up to 50% supplemental protein of soybean meal with equal proportion of supplemental protein from SWM and CLM had no deleterious effects on rate and efficiency of weight gain in broiler chickens. While nutrient and energy digestibility and carcass characteristics except dressing percentage were unaffected by dietary treatment, there was indication that organs such as gizzard and small intestine were significantly tasked for digestive function, evident from the considerable increase in their weights in birds fed diets in which over 50% of soybean protein was replaced by SWM and CLM. Based on the observation from this study, it can be concluded that not more than 50% of the dietary protein contributed by soybean should be replaced by SWM and CLM as doing otherwise would bring about a worsening effect on the performance of broilers.

PSV-19 Pasture history and supplementation affects parasite status of naïve lambs in grazing systems

Developing alternative parasite management strategies is critical as anthelmintic resistance continues to be a global concern in small ruminant grazing operations. Converting cropland to pastureland may serve as one strategy to develop parasite free pasture, thus reducing the need for anthelmintic treatment. The objective of this study was to evaluate the impact of pasture contamination with gastrointestinal parasites and protein supplementation on the mitigation of parasitic infection in grazing lambs. We hypothesized that lambs grazing on newly established pasture (clean) without supplementation would perform similarly to those lambs grazing on permanent sheep pasture (infected) provided supplementation. A total of 96, 60-day old lambs (30 kg ± 4.0 kg), were randomly assigned to one of four treatments: 1) clean pasture without supplementation (CN); 2) clean pasture with supplementation (CS); 3) infected pasture without supplementation (IN); and 4) infected pasture with supplementation (IS). Packed cell volume (PCV) and fecal egg counts (FEC) were monitored biweekly. Data were analyzed using PROC MIXED in SAS. Based upon fecal egg fluorescence, 66% of the fluoresced eggs in the mixed infection population were Haemonchus contortus. There was a pasture × supplementation × day effect for PCV in that CN lambs had a greater PCV than IS lambs on days 28, 42, 56, and 70 (P &lt; 0.0001). However, on days 98 and 112, IS lambs had a greater PCV than CN lambs (P &lt; 0.001). In addition, there was a pasture × supplementation × day effect for FEC such that IS lambs demonstrated a greater FEC over time from day 28 to day 112 compared to CN lambs (P &lt; 0.001). Offering supplemental protein to lambs grazing pastures contaminated with gastrointestinal parasites may help lambs cope with a heavy parasite burden. Therefore, developing additional management strategies will be key in reducing the future use of anthelmintics.

66 Effects of level of protein supplementation on intake of wheat straw and drinking water varying in salinity by Boer and Spanish goats

The effect of level of supplemental protein on intake of wheat straw by yearling meat goats drinking saline water was determined. Eighteen Boer and 18 Spanish wethers (initial BW 37.5±0.97 and 34.0±0.41 kg, respectively) consumed straw ad libitum supplemented with soybean meal DM at 0.14 or 0.28% BW (LP and HP, respectively) during 2 4-wk phases. Phase-1 water treatments were fresh water [FW; 233 ppm total dissolved salts (TDS)] and FW with 10,000 and 15,000 ppm TDS added via NaCl (MS and HS, respectively). The added TDS level for HS was 20,000 ppm in phase 2. In the preceding 8 wk, MS- and HS-wethers consumed water with 5,000 and 10,000 ppm TDS, respectively. There were no interactions between supplement and water treatments in water or DMI in the last 2 wk of phases. In phase 1, water intake varied among water treatments (1,075, 1,080, and 1,362 g/d; SEM=74.9) but was not influenced by supplement treatment (1,150 and 1,195 g/d; SEM=61.1), and DMI was similar for both water (603, 598, and 640 g/d for FW, MS, and HS, respectively; SEM=30.0) and supplement treatments (627 and 600 g/d for LP and HP, respectively; SEM=24.5). In phase 2, there was a breed×water treatment interaction (P = 0.039) in water intake (1,038, 1,178, and 1,907 for Boer and 744, 1,029, and 1,340 g/d for Spanish consuming FW, MS, and HS, respectively; SEM=77.7). However, straw intake was not influenced by water (717, 736, and 759 g/d for FW, MS, and HS, respectively; SEM=36.4) or supplement treatment (732 and 743 g/d for LP and HP, respectively; SEM=29.7). In conclusion, with relatively high levels of TDS in drinking water achieved by NaCl addition, a high level of supplemental protein did not enhance intake of wheat straw. However, future research should address other types of saline water.

Impact of Protein Supplementation and Presumptive Treatment for Enteric Pathogens on Infant Growth from 6–12 Months of Age: Results of a Cluster-Randomized Controlled Trial

Objectives Intake of high-quality protein may be insufficient to support growth in the context of high enteric pathogen carriage and environmental enteric dysfunction. Our objective was to test whether supplemental protein, with or without presumptive treatment for enteric pathogens, would improve infant growth from 6–12 months of age. Methods We conducted a 2 × 4 factorial cluster-randomized trial in rural Bangladesh. The first factor was azithromycin treatment (10 mg/kg * 3 days) or placebo at 6 & 9 months of age. The second factor, delivered from 6–12 months of age, consisted of: supplemental protein as daily porridge (125 kcal/d, with 10 g protein/day as egg white powder) or a daily egg; an isocaloric daily porridge; or nutrition education alone. The present aim tested the impact of the protein-rich porridge, with or without azithromycin treatment. All infants born in the study area over a 9-mo period were eligible and consented at ∼3 mo of age. Trained field workers measured infant size at 6, 9, and 12 mo of age using standardized protocols. We used linear regression with generalized estimating equations to test the interventions’ impact on anthropometric indices, respectively, at 12 mo of age, controlling for baseline measures. Analysis was intention-to-treat. Results Overall, 2205 infants were enrolled from 282 clusters and exposed to both nutrition (1074 in protein arm from 140 clusters; 1074 in the isocaloric arm from 142 clusters) and presumptive treatment interventions. At baseline, 18.7%, 16.9%, and 6.4% of infants were stunted, underweight, and wasted, respectively. There was no statistical interaction between protein supplementation and azithromycin treatment for any of the anthropometric indices, so groups were combined. In the analysis of main effects, added protein had no impact on mean length-for-age (β = 0.01; 95% CI: −0.06, 0.08), weight-for-age (β = −0.002; 95% CI: −0.06, 0.05), or weight-for-length (β = −0.04; 95% CI: −0.12, 0.05) Z-scores at 12 mo of age. Conclusions Supplemental protein from 6–12 mo of age had no effect on mean linear or ponderal growth measured at 12 mo of age, irrespective of presumptive treatment for enteric pathogens with azithromycin. Funding Sources The Bill and Melinda Gates Foundation.

76 Does supplemental protein and rumen-protected methionine improve performance and digestibility during late-gestation in beef cows?

Methionine (MET) is likely the first limiting amino acid in low-protein forages fed to beef cattle during late-gestation. Therefore, the objective of this study was to determine if supplemental protein and rumen-protected MET improve cow performance and apparent tract digestibility (TTD) during late-gestation. This study used 147 late-gestation Angus crossbred cows and heifers in a 3x2 factorial arrangement for dietary treatments. The cattle were randomly assigned to one of six diets formulated to 90, 100 or 110% of metabolizable protein (MP) requirements (NRC, 2016), with (without) 9 g/d of rumen-protected MET (MetaSmart, Adisseo Inc.). These diets were fed for approximately 8 wks before calving. All data was analyzed as a randomized block design using SAS 9.4 PROC GLIMMIX procedure. Cows fed at 90% MP requirements lost body weight (BW), while cows fed at 100% and 110% MP requirements maintained and (or) gained BW over the trial (P = 0.02). Similarly, cows fed at 90% MP requirements lost more pregnancy corrected BW than cows fed at 100% and 110% MP requirements (P = 0.01). However, supplemental MET did not affect body weight gains (P &gt; 0.07). Cows and heifers fed at 90% MP requirements had reduced TTD for crude protein compared to cattle fed to 110% MP requirements (P &lt; 0.001), MET supplementation did not impact TTD (P &gt; 0.20). Additionally, cattle fed at 90% MP requirements had increased serum cholesterol and reduced urea concentrations compared to cows fed to 100% and 110% MP requirements (P &lt; 0.0001). MET supplementation increased serum concentrations for glucose, isoleucine, leucine, lysine, serine, threonine and valine (P &lt; 0.02). Calf birth weights were not significantly impacted by dietary treatment (P &gt; 0.31). Feeding cows above their MP requirements may improve late-gestation performance and CP digestibility. Supplemental MET may increase amino acid utilization but did not improve beef cow performance or digestibility parameters measured in late-gestation.

395 Effects of supplemental protein and yeast on fermentation of low quality forage in single-flow continuous culture fermenters

Various anecdotes suggest the combination of supplemental protein and yeast improve utilization of low-quality forage. Two studies were conducted to evaluate effects of a commercially available supplement containing protein and yeast on fermentation in single-flow continuous culture fermenters. In Exp. 1, Bermuda grass with no supplement (NCON1), dried distillers grains (PCON1), and two commercially available supplements Diamond V XP (DV1) or SweetPro 16 (SP1) were compared. In Exp. 2, K31 tall fescue with no supplement (NCON2), supplemental dried distillers grains (PCON2), and two commercially available supplements Diamond V XP (DV2) or SweetPro 16 (SP2) were compared. Twenty-four single flow fermenters (1470mL) were randomly assigned to treatments and fed twice daily for 8 d, 5 d of adaptation and 3 d of collection. In both experiments, digestibility of DM, OM, NDF, and ADF were not influenced by supplementation regardless of source (P &gt; 0.10). In Exp. 1, NH3-N concentration increased (P &lt; 0.01) for DV1 over both NCON1 and PCON1 and was greatest for SP1 (P &lt; 0.01). Greater amounts of NH3-N and microbial N were recovered from fermenter overflow when SP1 was supplemented (P &lt; 0.01). Crude protein (CP) degradation was also greatest for SP1; however, when supplement was included, regardless of source, CP degradation was increased over NCON1. Acetate, propionate, butyrate, and total VFA levels were similar (P &gt; 0.10) amongst NCON1, PCON1, and DV1 and greatest when SP1 was supplemented. In Exp. 2, fermenter NH3-N concentration was greatest for SP2 (P &lt; 0.01) and similar amongst NCON2, PCON2, and DV2 (P &gt; 0.01). No differences were detected (P &gt; 0.10) between treatments with respects to CP degradation. Total VFA concentrations increased over time regardless of treatment during the second study.

375 The effect of supplemental protein from weaning until first breeding on heifer development and uterine environment characteristics

Replacement heifer development is one of the most critical components of productive beef operations. By identifying the ideal uterine environment in pre-breeding heifers, fertility and reproductive efficiency can be maximized. Our hypothesis was that different levels of protein supplementation would affect the rate of development and uterine environment of beef heifers. To test the effects of dietary supplementation on these outcomes, a randomized complete block design with repeated measures was implemented. Commercial Angus heifers (n = 60) were blocked by BW into 4 weight classes. Within each weight class, three pens of 5 heifers each were randomly assigned to one of three treatment groups of supplemental protein [10% (control), 20% (P20), and 40% (P40)]. All heifers were allowed access to ad libitum grass hay. Bodyweight and BCS were collected every 2 weeks to monitor heifer development. Uterine fluid samples were collected monthly by flushing with sterile saline to evaluate components of the uterine environment. Relative uterine pH was calculated by subtracting saline pH from the uterine flush pH. Separate mixed model ANOVAs and mean separation via PROC GLIMMIX (SAS 9.4, Cary, NC) were used to determine if protein supplementation treatments, time and their interactions influenced BW, BCS, or uterine environment. Bodyweight of the control group was significantly lower (P &lt; 0.05) than P20 or P40 groups from December to March. There was an interaction between treatment and time for relative uterine pH (P = 0.002). In November, the P40 group exhibited less change in pH compared to the control group (0.33±0.1 vs. 0.74±0.1; P &lt; 0.05). Whereas in December the P40 (0.23±0.1) group showed more basic uterine environment compared to the P20 (-0.22±0.1) or control (-0.13±0.1) groups (P &lt; 0.05). In conclusion, higher protein supplementation does improve heifer growth and development, as well as altering the pH of the uterine fluid from weaning to first breeding