Effects of four mono- and sesquiterpenes on the consumption of alfalfa pellets by sheep.

Effects of individual terpenes on alfalfa pellet intake by lambs were examined in four experiments. Forty-five lambs (nine lambs/treatment) were individually fed alfalfa pellets sprayed with either camphene, myrcene, caryophyllene oxide, or beta-pinene at one of five concentrations (one terpene per experiment). Treatments (0, 0.5, 1, 2, and 10x) were multiples of the concentration (x) of a specific terpene in tarbush. Terpenes were applied to alfalfa pellets (0.64 kg x lamb(-1) x d(-1), DM basis), and consumption was measured during a 20-min interval for 5 d. Lambs were maintained and fed alfalfa pellets in one group (except during 20-min tests) at a mean total daily intake of 4.7% of BW (DM basis). Camphene and caryophyllene oxide tended to decrease intake (linear contrasts were P = .0651 and P = .0504, respectively), whereas myrcene and beta-pinene exerted no effect on the consumption of alfalfa pellets by lambs. Camphene and caryophyllene oxide may be involved in the differential herbivory of individual tarbush plants by livestock.

Pen confinement of yearling ewes with cows or heifers for 14 days to produce bonded sheep.

Mixed species stocking is commonly a more ecologically sound and efficient use of forage resources than single species stocking, especially in pastures having complex assemblages of forage species. However, in many environments livestock predation on especially smaller ruminants adds an extra challenge to mixed species stocking. When mixed sheep and cattle remain consistently as a cohesive group (flerd), predation risks are lessened, while fencing and herding costs are reduced. To establish a cohesive group (bond), a 30-day bonding period in which young sheep and cattle pairs are penned together is currently recommended. The purpose of this research was to test if a bond could be produced in <30 days (14 days) using pen confinement; thus reducing feed, labor, and overhead costs. Additionally, we tested whether cow age affects cohesiveness of bonded pairs immediately following 14 days of pen confinement. Sixteen mature cows (7-8 years of age) and sixteen 9-month-old heifers were randomly paired with one of 32 yearling ewe lambs. Eight cow/ewe (PC) and eight heifer/ewe (PH) pairs were maintained individually in 2mx6m pens for 14 days. The other eight-cow/ewe (NC) and heifer/ewe (NH) pairs were separated by species with each species maintained on separate pastures for the 14-day period. After 14 days, pairs were released in observation paddocks and separation distance between treatment pairs was measured during a 30-min open field test. Other behaviors were also noted and recorded during the field test. Separation distance did not differ (P=0.973) between the PC and PH treatments; however, separation distance for NC versus NH (P<0.004), NC versus PC (P<0.001), and NH versus PH (P<0.002) all differed. Mean separation distance (meters) and standard errors were 40+/-3.9, 3+/-0.3, 76+/-5.3, and 4+/-1.4 for NH, PH, NC, and PC treatments, respectively. Overall, the animals that were penned spent more time grazing and less time walking than animals not previously penned for 14 days. Penned animals also vocalized less than non-penned animals during the open field test. The bond sheep formed to the bovines was not affected by cow age. These data suggest that inter-specific bond formation using pen confinement can be accomplished within 14 days, representing a 53% savings in time and associated costs when compared to pen confinement lasting 30 days.

Extracts of Flourensia cernua reduce consumption of alfalfa pellets by sheep.

Effects of three extracts (hexanes, ether, and ethanol) from tarbush (Flourensia cernua) on intake of alfalfa pellets by lambs were examined. Forty-five ewe lambs were fed one of five treatments for five days (randomized complete block, three lambs per block on each treatment). Treatments were alfalfa pellets (CON) or alfalfa pellets plus ethanol carrier (CAR), hexanes extract (HEX), ether extract (ETH), or ethanol extract (ETOH). Extracts were applied to alfalfa pellets at the same concentration as in an equivalent amount of tarbush (as fed basis) in experiment 1 and at 10-fold dilutions of that concentration in experiment 2. Treatments were isolated from tarbush leaves by using a sequential extraction with hexanes, diethyl ether, and 100% ethanol. Lambs received 640 g of alfalfa pellets (dry matter basis) each morning and intake was monitored during a 20-min interval. Lambs were maintained and fed alfalfa pellets (4.7% of body weight) as one group except during this interval. In experiment 1, mean intake by lambs during the 20-min interval was 361, 393, 204, 212, and 228 g for CON, CAR, HEX, ETH, and ETOH, respectively (SEM = 28.9). All three extracts decreased intake (P < 0.001) compared to CON or CAR. Intake did not differ among the three extracts (HEX, ETH, and ETOH) or between the two controls (CON and CAR). Mean intake did not differ among treatments in experiment 2 (468, 455, 389, 381, and 431 g for CON, CAR, HEX, ETH, and ETOH, respectively; SEN = 30.5; P = 0. 187). Several compounds are probably responsible for the low palatability and differential use of tarbush typically exhibited by livestock.

Effect of individual terpenes on consumption of alfalfa pellets by sheep.

We examined effects of individual terpenes on alfalfa pellet intake of lambs in five experiments. Forty-five lambs (nine lambs/treatment) were individually fed alfalfa pellets sprayed with either p-cymene, alpha-humulene, 1,8-cineole, 3-carene, or sabinene at one of five concentrations (one terpene per experiment). Treatments (0, .5, 1, 2, and 10x) were multiples of the concentration (x) of a specific terpene in tarbush that was related to differential herbivory by livestock in previous studies. Terpenes were applied to alfalfa pellets (.64 kg x lamb(-1) x d(-1), DM basis), and consumption was measured during a 20-min interval for 5 d. Lambs were adapted to handling and pen feeding for 10 d and were maintained and fed alfalfa pellets in one group (except during 20-min tests) at a mean total daily intake of 4.7% of BW (DM basis). None of the five compounds decreased alfalfa pellet consumption during the 20-min interval. These five mono- and sesquiterpenes do not seem to be responsible for differential herbivory of individual tarbush plants by livestock.

Effects of volatile compounds on consumption of alfalfa pellets by sheep.

We examined the effects of six volatile compounds on alfalfa pellet consumption by lambs. In each experiment, 45 lambs were individually fed alfalfa pellets sprayed with a selected compound (camphor, limonene, cis-jasmone, beta-caryophyllene, borneol, or alpha-pinene) at one of five concentrations. Treatment concentrations were multiples (0, .5, 1, 2, and 10) of the concentration of a specific compound (X) that was related to differential herbivory of tarbush by livestock in previous studies. Treatments were applied to alfalfa pellets (.64 kg x lamb(-1) x d(-1), DM basis), and consumption was measured during a 20-min interval each morning for 5 d. Lambs were adapted to handling procedures and the pelleted diet (without treatments) for 10 d. Lambs were maintained and fed (approximately 4.5 to 5% of BW) as one group except during 20-min tests. A negative linear effect of treatment concentration on intake was observed for camphor (P < .02) and alpha-pinene (P < .01), and a quadratic response was detected for borneol (P < .02). The other three compounds had no discernible effect on consumption. Although volatile compounds generally had only minor influences on consumption, the negative influences of alpha-pinene and camphor concentrations on pellet consumption suggest that these monoterpenes may partially explain differential herbivory of individual tarbush plants by livestock.

Effect of chronic ingestion of tarbush (Flourensia cernua) on ewe lambs.

Efforts to increase livestock utilization of tarbush are being coupled with studies to examine tarbush toxicity. Thirty-eight (19/treatment) ewe lambs were assigned at birth to receive either tarbush or alfalfa (15%, dry matter basis) in a sorghum-based growing ration. Lambs were pen-fed this diet 60 d pre-weaning and 60 d post-weaning. No differences existed between treatments in feed consumption. In the tarbush group, 1 lamb died of unknown causes at 90 d of age, while 3 lambs died between 115 and 120 d of age. There were no deaths in the alfalfa group. Shortly before death, lambs fed tarbush appeared lethargic, disoriented and anorectic. At 122 d of age, 5 lambs were randomly selected from each group. Feces and jugular blood samples were obtained from each lamb before being euthanized and necropsied the following day. All fecal samples were negative for occult blood. Serum gamma glutamyl-transpeptidase (P < 0.001) and aspartate aminotransferase (P < 0.001) activities and platelet counts (P < 0.05) were elevated in lambs fed tarbush, while serum calcium concentrations tended (P < 0.10) to be greater. Histologic examination revealed diffuse liver apoptosis in lambs fed tarbush. These data indicate tarbush leaves cause liver damage when fed for extended periods of time.

Effects of organic solvents on use of tarbush by sheep.

Tarbush (Flourensia cernua DC) is a native perennial shrub prevalent in many parts of the Chihuahuan Desert. Ruminants have exhibited limited use of tarbush leaves and new leaders as a forage during the summer growing season. Efforts to increase use of tarbush by lambs through spraying with various organic solvents were unsuccessful, probably because of the highly variable response. However, complete immersion of tarbush in organic solvents (acetone and ethanol) increased (P<0.01) tarbush use by ram lambs when compared to unaltered tarbush. Data suggest that removal of secondary compounds from the leaf surface of tarbush using organic solvents enhanced acceptability of tarbush to sheep.

Creosotebush vegetation after 50 years of lagomorph exclusion.

In 1939, an experiment was established on the Jornada Experimental Range to evaluate the effects of shrub removal, rabbit exclusion, furrowing, and seeding in creosotebush [Larrea tridentata (DC.) Cov] vegetation. Sixteen plots (21.3×21.3 m) were laid out in four rows of four plots per row with a buffer zone of 7.6 m between plots and rows. A barbed wire fence excluded cattle and poultry wire fencing excluded lagomorphs. Treatments were factorially applied at two levels. Plant cover in the plots was sampled in 1938 (before treatment), 1947, 1956, 1960, 1967 and 1989 with randomly located, line-intercept transects. Data from all sampling dates were analyzed as a split plot in time and main effects for 1989 tested by analysis of variance for a 2×4 factorial experiment. There were significant (P<0.10) year x treatment interactions. Seeding and furrowing treatments were ineffective but lagomorph exclusion and shrub clearing treatments resulted in significant treatment differences for several species. In 1989, basal area of spike dropseed (Sporobolus contractus A.S. Hitchc.) was 30-fold greater on the lagomorph excluded than on the lagomorph unexcluded treatment. Canopy cover of honey mesquite (Prosopis glandulosa Torr. var. glandulosa), tarbush (Flourensia cernua DC.) and mariola (Parthenium incanum H.B.K.) were affected by lagomorph exclusion. None of the responses were viewed as successional in nature. They principally represented individual species sensitivities to either absence of a primary herbivore or removal of aboveground shrub biomass. Though the physical treatments could be regarded as relatively severe disturbances of the system, the impacts on community vegetation dynamics were relatively insignificant.

Grazing behavior of rangeland beef cattle differing in biological type.

Grazing behavior exhibited by different biological types (breed groups) of lactating beef cows was evaluated during the summers of 1985 (Trial 1) and 1986 (Trial 2). Animals grazed native Montana foothill grassland. In Trial 1, breed groups consisted of Hereford (HH), 50% Angus-50% Hereford (AH), 50% Simmental-50% Hereford (SH), and 75% Simmental-25% Hereford (3S1H) with six cows per breed group. Daily grazing hours were 11.8 +/- .2, 12.3 +/- .2, 11.6 +/- .2, and 11.6 +/- .5 h/d for HH, AH, SH, and 3S1H, respectively. There was a tendency for AH cows to graze longer than HH and SH cows (P = .10). Bite rates were 52.7 +/- 1.5, 56.2 +/- 1.5, 53.2 +/- 1.4, and 59.0 +/- 1.6 bites/min for HH, AH, SH, and 3S1H, respectively. The AH and 3S1H cows had higher bite rates (P less than .05) than the HH and SH cows. Means for distance traveled were 3.1 +/- .2, 3.4 +/- .2, 4.0 +/- .2, and 2.8 +/- .2 km/d for HH, AH, SH and 3S1H, respectively. The SH cows tended to travel farther (P less than .10) than cows of other breed groups. The AH traveled farther than the 3S1H but did not differ from the HH. In Trial 2, breed groups were Hereford (HH), Tarentaise-Hereford (TH), Tarentaise-Simmental-Hereford (T(SH], and Charolais-Simmental-Hereford (C(SH]; each group included six lactating cows. Means for bite rate were 56.9 +/- 1.1, 58.7 +/- 1.1, 60.9 +/- 1.0, and 59.0 +/- 1.1 bites/min for HH, TH, T(SH), and C(SH), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of milk intake on forage intake and performance of suckling range calves.

A study to examine the relationships between milk intake, forage intake, and performance of Hereford-Angus suckling range calves was conducted during July, August, and September of 1984 and 1985. Twenty calves were used each year. The study was conducted at the Red Bluff Research Ranch located 56 km west of Bozeman, Montana. Average daily gain, milk intake (MI), forage digestibility, and fecal output (FO) were measured at 28-d intervals, beginning when the average calf age was 66 +/- 4 d. Milk intake was estimated using weigh-suckle-weigh techniques. Total fecal collections were used to measure FO. Forage digestibility and rates of passage were determined using nylon bag in situ techniques and external markers in ruminally cannulated calves of the same age. Fecal output by calves increased as body weight and age increased. Milk intake was higher (P less than .05) in 1985 than in 1984, but FO was higher (P less than .01) in 1984 than in 1985. Fecal output by calves was negatively correlated to MI in July (r = -.62; P less than .05) and August (r = -.56; P less than .05). No significant correlations were detected between MI and ADG (P greater than .10). Forage intake estimates were derived from FO, rate of passage, and in situ digestibility values. During July, calves consumed .3 kg more forage for each kilogram of reduction in fluid MI (P less than .05). In both August and September, calves consumed .6 kg more forage for each kilogram of reduction in fluid MI (P less than .10). Calves maintained similar digestible energy (DE) intake both years, although the source of DE varied.

Substitution of DL-methionine for soybean meal as a winter supplement for gestating cows grazing native range.

A winter grazing study was conducted to determine whether DL-methionine could replace soybean meal as a N supplement for gestating beef cows. During two winters (Trial 1, n = 51; Trial 2, n = 60), crossbred beef cows grazed native foothill range. Three treatment groups were supplemented with either none (CON), DL-methionine (7.5 g Trial 1 and 9 g Trial 2) in .5 kg beet pulp carrier (BPM) or .4 kg soybean meal (SBM). Cows were supplemented individually every other day. Small differences were noted in cow BW, condition score and blood metabolites. Unsupplemented cows lost the greatest amount of BW (P less than .01) in both trials and lost more (P less than .05) condition during Trial 1 than cows fed BPM or SBM supplements. Blood samples were obtained on two consecutive days during each trial (45 d and 25 d prepartum) and analyzed for blood urea N, total bilirubin, creatinine, albumin, total protein and cholesterol. A treatment x day preparatum interaction (P less than .05) was noted for blood urea. Blood urea nitrogen declined as gestation length increased for CON and SBM cows, but blood urea of BPM-supplemented cows remained low and unchanged. In situ forage digestion was measured in 12 ruminally cannulated cows (four/treatment). In both trials, in situ rate of NDF disappearance was greater (P less than .05) for SBM than for BPM. In Trial 2, a treatment x sampling hour interaction was detected for purine concentration of whole ruminal contents; SBM maintained greater purine concentrations throughout the 48-h supplementation cycle than BPM did. Principal component analysis suggested that ruminal ammonia limited the microbial growth response to DL-methionine. Therefore, alternate-day supplementation of DL-methionine plus beet pulp did not effectively substitute for soybean meal in these trials.

The effects of ruminal escape protein or fat on nutritional status of pregnant winter-grazing beef cows.

This study was designed to determine the influence of soybean meal supplementation, with or without additional ruminal escape protein or fat, on the nutritional status of pregnant winter-grazing beef cows. During two winters (Trials 1 and 2), approximately 60 prepartum beef cows grazed native foothills range each year. Cows were allotted randomly to five groups and supplemented (g/d) with either none (control); 570 soybean meal (SOY); 450 soybean meal plus 230 blood meal (SOY + BM); 140 soybean meal, 16 urea plus 450 corn gluten meal (SOY + CGM); or 570 soybean meal plus 210 animal fat (SOY + FAT). These supplements were designed to supply similar quantities of ruminal degraded protein while varying in escape protein quantity and source (SOY + BM and SOY + CGM). Condition scores and body weights were determined at trial initiation (mid-December) and conclusion (early March). Eight blood samples obtained over 4 d during three periods (9, 4 and 1 wk prior to parturition) were analyzed for concentrations of glucose, urea nitrogen (N), total bilirubin, creatinine, albumin, total protein and cholesterol. Cows in the control treatment experienced the greatest BW loss in both trials. In Trial 2, escape protein tended to decrease (P less than .06) BW loss compared to SOY, though loss tended to be greater (P less than .08) with SOY + CGM than with SOY + BM. Escape protein can enhance nutritional status when supplemented with .6 kg/d of soybean meal.