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Twenty Hampshire lambs (31 ± 4 kg BW) in individual metabolism cages were used in a 10-treatment by 2-period (n = 4) trial to evaluate the interaction between protein supplementation and sulfate water on intake and metabolic responses when lambs were fed low-quality grass hay (Megathyrsus maximus; 6.4% CP, 79.5% NDF). The treatment structure was a 2 × 5 factorial: 2 water qualities (WQ; low-sulfate [LS] and high-sulfate [HS]; 442 and 8,358 mg/kg total dissolved solids, respectively) and 5 soybean meal levels (SBM; 0%, 0.25%, 0.50%, 0.75%, and 1.00% BW/d). After 15 d of adaptation, periods consisted of 5 d for determination of forage and water intake, nitrogen balance, and digestion measurements (d 16 to 20) and 1 d for blood sampling and determination of ruminal hydrogen sulfide (H2S) concentration (d 21). Supplemental SBM × WQ interactions were significant for forage OM intake (P = 0.04) and total OM intake (P = 0.04), whereas a tendency was observed for total tract digestible OM intake (P = 0.07). Intake values of LS lambs were higher than those of HS lambs (P < 0.05) in only the first and second levels of SBM. Water intake increased linearly (P < 0.01) with SBM level but was not affected by WQ (P = 0.39). Water quality and SBM supplementation affected total tract OM digestibility (TTOMD; P < 0.01); LS lambs had lower TTOMD than HS lambs (P < 0.01). Plasma urea N increased linearly in response to SBM (P < 0.01) but was not affected by WQ (P = 0.11). Nitrogen balance was not affected by SBM × WQ interaction (P > 0.12), except for N utilization (N retained/N intake ratio; P < 0.01). Regardless of WQ, N intake (P > 0.01), N urine (P > 0.01), and N balance increased linearly (P > 0.01) with SBM level. Water quality adversely affected N intake and N balance, although at the highest level of SBM no differences in N balance were observed between LS and HS lambs (P = 0.85). No changes due to WQ were observed for either urea reabsorbed by kidneys (P = 0.63) or glomerular filtration rate (P = 0.30), but renal function was affected by SBM level (P < 0.01). There was a supplemental SBM × WQ interaction for ruminal H2S concentration (P < 0.01) due mainly to a greater concentration from 0.25% BW SBM in HS than in LS lambs. In conclusion, these results confirmed the existence of an interaction between sulfate water and supplemental protein, which alters intake and metabolic responses when lambs are fed low-quality grass hay. [ABSTRACT FROM AUTHOR]

An experiment was conducted to assess the impact of increasing levels of supplemental soybean meal (SBM; 45.7% CP) in cattle consuming tropical grass hay (Panicum maximum cultivar Gatton; 7.0% CP and 81.8% NDF) and drinking low salt water (LS) or high salt water (HS). Six ruminally fistulated beef steers (BW = 375 ± 43 kg) were used in a 6-treatment, 4-period crossover experiment. Treatments were arranged as a 2 × 3 factorial, with 2 levels salt in the water (LS and HS: 786 and 6,473 mg/kg of total dissolved solids [TDS], respectively) and 3 levels of SBM (0, 0.2, and 0.4% BW/d). After 15 d of adaptation to treatments, periods consisted of 5 d for intake and digestibility determination, 1 d for monitoring ruminal fermentation, 1 d for ruminal evacuation, and 1 d for blood sampling. Supplemental SBM × water quality interactions were significant (P < 0.05) for most measures of intake, except for total tract digestible OM intake (P = 0.38) and total tract digestible NDF intake (TTDNDFI; P = 0.32). At greater levels of SBM, forage OM intake, NDF intake, and water intake seemed to reach a plateau in LS while this was not observed in HS. Total tract digestible OM intake increased linearly (P = 0.01) and TTDNDFI tended to increase (P = 0.09) in response to increased SBM. Digestibility of OM and NDF were not affected by treatment (P > 0.21). Passage rate of acid detergent insoluble ash linearly increased (P< 0.01) in response to SBM, although it was not affected by water quality (P = 0.98). Total VFA concentrations and ruminal pH were not affected (P > 0.60 and P > 0.31, respectively) by treatment. Ruminal ammonia N levels were linearly increased by SBM supplementation (P < 0.01) but were not affected by water quality (P = 0.25). However, ruminal ammonia tended (P = 0.09) to be greater in HS at 0.2% of SBM supplementation. No interaction was observed for plasma urea N (PUN; P = 0.20). Plasma urea N was affected by SBM supplementation (P = 0.05) and water quality (P < 0.01). However, PUN did not differ for 0.4% SBM supplementation (P = 0.30) either at LS or HS treatments. In conclusion, a high level of SBM supplementation (0.4% BW) counteracted the detrimental effect of high TDS in drinking water on low-quality forage consumption by cattle. [ABSTRACT FROM AUTHOR]

Tannins in sainfoin (Onobrychis viciifo-lia) may bind to alkaloids in endophyte-infected tall fescue [E+; Lolium arundinaceum (Schreb.) Darbysh.] and attenuate toxicosis. If so, supplementing E+ with sainfoin will increase use of E+ by sheep, and polyeth-ylene glycol (PEG)--a polymer that selectively binds to tannins--will reduce such response. To test these predictions, thirty-six 2-mo-old lambs were randomly assigned to 3 treatments (12 lambs/treatment). Dur-ing exposure, all lambs were individually penned and fed E+ supplemented with beet pulp (CTRL), fresh-cut sainfoin and beet pulp (SAIN), or fresh-cut sain-foin plus PEG mixed in beet pulp (SAIN+PEG). Feed intake was measured daily. Rectal temperatures and jugular blood samples were taken at the beginning and end of exposure. After exposure, all lambs were offered choices between endophyte-free tall fescue (E-) and orchardgrass, and preference for E- was assessed. Then, all lambs were allowed to graze a choice of E+ and sainfoin or a monoculture of E+. The forag-ing behavior of lambs was recorded. When sainfoin was in mid-vegetative stage, lambs in SAIN ingested more E+ than lambs in CTRL (P = 0.05), but no differ-ences were detected between lambs in SAIN+PEG and CTRL (P = 0.12). Sainfoin supplementation improved some physiological parameters indicative of fescue toxicosis. Lambs in SAIN had lower rectal tempera-tures (P = 0.02), greater numbers of leukocytes (P < 0.001) and lymphocytes (P = 0.03), and greater plas-matic concentrations of globulin (P = 0.009) and pro-lactin (P = 0.019) than lambs in CTRL. Some of these differences were offset by the SAIN+PEG treatment. When lambs were offered choices between E- and orchardgrass, only lambs in SAIN had greater intake of E- than lambs in CTRL (P < 0.001). When lambs were allowed to graze a choice of E+ and sainfoin, all treatments used E+ to the same extent (P > 0.05). On the other hand, when they grazed on a monoculture of E+, lambs in SAIN+PEG showed greater acceptance of E+ than lambs in SAIN or in CTRL ÇP < 0.05). In summary, sainfoin supplementation alleviated several of the classic signs of fescue toxicosis and increased intake of endophyte-infected tall fescue. Tannins in sainfoin partially accounted for this benefit since feed-ing a polymer that selectively binds to tannins (PEG) attenuated some these responses. However, sainfoin supplementation during initial exposure to E+ did not lead to an increased preference for E+ during grazing. [ABSTRACT FROM AUTHOR]

This study determined whether early experiences by sheep with monotonous or diverse diets influence intake of unfamiliar flavors and feeds later in life. Thirty 2-mo-old lambs were randomly assigned to 3 treatment diets (n = 10): diverse (DIV), diverse with plant toxins (DIV+T), and monotonous (MON). Lambs in DIV received in 9 successive periods of exposure 4-way choice combinations of 2 foods high in energy and 2 foods high in protein from an array of 6 foods: 3 high in energy [beet pulp, oat grain, and a mix of milo:grape pomace (60:40)] and 3 high in digestible protein (DP) (soybean meal, alfalfa, corn gluten meal). Lambs in DIV+T received the same exposure as DIV, but 2 plant toxins, oxalic acid (1.5%) and quebracho tannins (10%), were randomly added to 2 of the feeds in each of the choice combinations. Lambs in MON received a monotonous balanced diet, made with a mixture of all 6 feeds detailed before. All treatments received their feed in 4 separate buckets. During exposure, treatments did not differ in total daily DMI (P = 0.31), but daily intake of ME was less (P < 0.02) and daily intake of DP was greater (P < 0.03) for lambs in DIV and DIV+T than for lambs in MON. Treatments did not differ in ADG or G:F (P > 0.05). After exposure, lambs were offered a familiar feed (wheat bran) containing novel flavors (maple, garlic, or bitter) and 2-way choices of novel feeds (fescue hay vs. corn distillers grains, rice vs. calf manna, and green peas vs. rolled oats). Intake of maple-flavored wheat bran tended (P = 0.08) to be greater for lambs in DIV than for lambs in DIV+T and MON. Intake of bitter-flavored and garlic-flavored wheat bran were greater (P = 0.03 and P = 0.04, respectively) for lambs in DIV and DIV+T than for lambs in MON. During 2-way choice trials, lambs in DIV, but not in DIV+T, showed greater intakes of fescue hay (P = 0.05) and rice {P = 0.04) than lambs in MON. Intake of green peas was greater (P = 0.03) for lambs in DIV and DIV+T than for lambs in MON. At the end of testing, lambs in DIV but not in DIV+T showed greater ADG than lambs in MON (P = 0.05). Thus, early exposure to diverse foods enhanced acceptance of novel flavors relative to early exposure to a monotonous ration. Early experience with diverse feeds plus plant toxins led to a less diverse diet than early experience with diverse feeds. Early exposure to diverse feeds may be beneficial in production systems that require rapid acceptance and high intake of unfamiliar feeds. [ABSTRACT FROM AUTHOR]