Anthelmintic and nutritional effects of heather supplementation on Cashmere goats grazing perennial ryegrass-white clover pastures

To investigate anthelmintic and nutritional effects of heather supplementation in goats grazing perennial ryegrass-white clover pastures, 40 dry Cashmere goats were randomly assigned to 4 treatments in a 2 x 2 factorial arrangement: 2 grazing management treatments (supplementation with heather vs. nonsupplementation) and 2 anthelmintic treatments (treatment vs. nontreatment). Goats grazed continuously from May to September 2004. At the end of the grazing period, the number of dead goats due to gastrointestinal parasitism was 1 in the group supplemented with heather and dosed with anthelmintic, 4 in the group that received neither supplementation nor anthelmintic, and 0 in the other 2 groups. For goats that did not receive anthelmintic treatment, the percentage of heather in the diet was negatively correlated with fecal egg count in August (r = -0.59, P < 0.05) and September (r = -0.49, P < 0.1) and positively correlated (r = 0.54, P < 0.05) with BW changes during the grazing season. Therefore, the correlation coefficient between BW change and fecal egg count was negative (r = -0.62, P < 0.05). Rumen ammonia concentrations were always lower in supplemented goats (P < 0.05). However, VFA concentrations were greater in goats consuming heather (58.9 vs. 50.9 mmol/L), which suggests that ruminal fermentation was not adversely affected by consumption of tannins. Heather availability in the vegetation might represent a valuable opportunity and sustainable method to control gastrointestinal nematode infections in a goat production system based on grazing perennial ryegrass-white clover pastures.     

Preferential grazing by cattle on glyphosate-treated fescue pastures

Cattle grazing preferences on fescue pastures treated with the herbicide glyphosate at a rate of 2.52 kg/ha by surface application were determined, and the time course of the effect was characterized. An initial grazing preference for treated pasture was observed for the first 5 to 7 days. Over the next 15 days, this preference was lost because of decreasing amounts of herbicide on the herbage and/or desiccation of the herbage.     

Growth performance of yearling horses grazing bermudagrass pastures at different grazing pressures

Body weight gains and height at the withers were measured in yearling geldings grazing bermudagrass (Cynodon dactylon [L.] Pers.) pastures with neither energy nor protein feed supplementation at stocking rates of 6.7, 8.0, 9.5 and 12.4 yearlings per hectare. Weekly forage samples were taken to estimate the quantity and quality of available forage. These samples were clipped and separated into three equal lengths to characterize upper, middle and lower thirds of the canopy and to determine relationships between available forage and yearling growth rate. Average daily gain was influenced by stocking rate, but gain in height was not affected by stocking rate. Average daily gain ranged from -.31 to .37 kg/d and was negatively related to stocking rate. A quadratic relationship between available forage and ADG was detected. However, a linear relationship between ADG and available forage in top layers of the canopy indicated that animal performance might have been limited by availability of top layer forage in pastures subjected to light grazing pressure.     

An assessment of the effects of ruminal selenium pellets given to young sheep grazing selenium-deficient pastures

Thirty-eight species of small cetaceans termed “dolphins” and “porpoises” are listed. This review is a contribution to the growing community and veterinary interest in the welfare and diseases of these animals.     

留茬高度对人工草地牧草产量及质量的影响

试验对黑麦草／白三叶混播草地在不同留茬高度下的生产特性进行了分析研究,研究结果表明,草地牧草的枯死率与留茬高度呈正比关系,在不同留茬高度下,草地牧草青绿物质的生长速度和产量呈抛物线形式变化;青绿牧草产量占牧草总产量的百分比随留茬高度的上升而下降,而死亡物质的数量占牧草产量的百分比随留茬高度的上升而增加。     

Escape protein supplementation of yearling steers grazing smooth brome pastures

Two grazing trials utilizing individually supplemented yearling steers were conducted to study the effect of supplemental escape protein on steer performance during the active growth periods, spring and fall, of smooth brome (Bromus inermis). Graded levels (0, .11, .23 and .34 kg.head-1.d-1) of an equal-protein-basis mixture of bloodmeal and corn gluten meal were offered daily, replacing corn starch, which was used as the negative control. All steers received 582 g supplemental dry matter per day. Supplementation with escape protein improved daily performance in both spring (P less than .01) and fall (P less than .02). Analysis of pooled data from both trials indicated a linear (P less than .01) and quadratic (P less than .05) increase in steer performance with increasing level of escape protein in the diet. Analysis of grass samples collected throughout and composited over each trial demonstrated that grass protein was highly degraded in the rumen. Using a modified dacron bag technique, 12-h degradability was found to be 80 to 90% of the potentially digestible protein fraction. Rates of protein degradability were 14 and 11.7%/h. Assuming 5%/h rate of passage, escape protein was calculated to be 9.2 and 13.1% of total protein. As a result of the significant growth response observed above that of the energy-supplemented controls and the high ruminal protein degradabilities of the grass observed in the laboratory, it was concluded that growing ruminants grazing actively growing smooth brome pastures were deficient in metabolizable protein.     

Morphological changes in the organs of ewes grazing oestrogenic subterranean clover

The morphological effects of phytooestrogen exposure were determined in 10 ewes exposed to subterranean clover for 60 days, compared with 10 controls. In a second experiment, the time course of the development of the changes was studied. Typically oestrogenic changes were observed in ovary, oviduct, uterus, cervix, vagina and mammary glands. There was an early increase in cervical mucus, followed by a decrease. The delta basophils of the pituitary became degranulated, and hyperactive in appearance. The adrenal and thyroid glands increased in weight, and thyroid epithelium increased in height. There appeared to be a temporary increase in neurophysin storage in the hypothalamus, and shrunken, hyperchromatic neurones were observed in the hypothalamus of some affected ewes. All changes were observed within three weeks of exposure.     

Effects of eight grazing systems on carcass mass gains of steers grazing irrigated Cynodon aethiopicus pastures

Abstract

Eight grazing systems were compared on irrigated Cynodon aethiopicus pastures which received 650 kg N, 36 kg P and 200 kg dolomitic limestone/ha, annually. There were either one, two, three, six or 18 paddocks in the systems, the single paddock system being continuously grazed. The others were rotational systems with various periods of grazing and of resting.

Using the comparative slaughter technique carcass mass gains of crossbred Hereford/Afrikaner steers were calculated. Three‐year mean carcass mass gains over stocking rates from 12 to 18 steers/ha ranged from 872 to 997 kg/ha. None of the rotational systems were better than continuous grazing.

Estimates of amounts of herbage available for grazing in each system showed that there was least in the continuous grazed and most in the multi‐paddock systems where there were long periods of rest between successive grazing.     

Estimation of daily milk yield of Nellore cows grazing tropical pastures

Beef cows’ milk yield is typically determined by measuring milk yield once daily and then doubling this value to estimate daily production. However, it is not known whether this is accurate. Thus, we aimed to determine the association between morning and afternoon milk yield in grazing Nellore cows. Eighty Nellore cows were used, with initial weight of 516.0?±?1.0 kg. The experiment was a completely randomized factorial scheme, with 20 replications and four treatments (i.e., +?or ??pre-partum supplementation in combination with +?or ??post-partum supplementation): PRMM—1 kg of supplement/cow/day for 90 days pre-partum; MMPS—1 kg of supplement/cow/day for 90 days post-partum; PRPS—1 kg of supplement/cow/day for 90 days pre-partum and 90 days post-partum; and MM—only mineral mix ad libitum during pre- and post-partum. Milk was sampled on days 45, 135, and 225 post-partum (early, middle, and late lactation, respectively). No effects were observed of pre- and post-partum supplementation on milk yield (P?>?0.05). The afternoon/morning proportion of 0.45 in the early third of lactation was higher than other stages, which had a proportion of 0.41 (P?<?0.05). Post-partum supplementation increased milk protein in the morning and afternoon milking (P?<?0.05). There was also no effect of pre- and post-partum supplementation on afternoon-morning proportion other milk components (P?>?0.05). We conclude that estimating daily milk production of grazing beef cattle by multiplying a once daily milking amount times two is not accurate. Under the conditions of this study, proportion of total daily production represented by the ratio of afternoon/morning milking was 0.45 in early lactation (first third) and 0.41 in mid- and late lactation.     

An epidemiological study of trichostrongylidiasis in dairy cattle grazing irrigated pastures

Trichostrongylid burdens in 1 to 2-year-old dairy heifers were estimated after they grazed with a dairy herd for up to 12 months. Ostertagia ostertagi, Trichostrongylus axei and Cooperia oncophora represented 79.5, 12.7 and 7.8% respectively of all trichostrongylids recovered. The largest burden was 97,000 trichostrongyles with less than 20,000 being the typical burden. Clinical disease was not observed. The strain of O. ostertagi present was capable of inhibition and was not necessarily controlled by anthelmintics. Availability of infective larvae increased with the onset of spring when "modified tracer" calves accumulated up to 30,000 trichostrongyles over intervals of one month. From July to September each year, up to 80% of the Ostertagia burden in these animals were inhibited larvae. Faecal strongyloid egg counts fell from less than an average of 60 eggs per gram to 10 eggs per gram when the heifers were one and 2 years old, respectively. Mature cows continually passed few eggs in their faeces.     

Energetic efficiency of milk synthesis in dual-purpose cows grazing tropical pastures

The aim of this study was to assess the energetic efficiency of milk synthesis by grazing dual-purpose cows with or without a starch-based supplement in tropical South Mexico. Forty-six Holstein × Zebu cows were used in a 2 × 2 × 2 factorial design. Factors analysed were diet (supplemented, unsupplemented), age (young: 1–2 calvings, mature: >3 calvings) and day of lactation (21 and 84 days post-calving). The supplement represented about 30% of estimated dry matter (DM) intake. Grass intake was measured using the n-alkane technique at 21 and 84 days post-calving when calculations of efficiency were performed. Efficiency for milk synthesis was reported as feed conversion efficiency (FCE, kilograms of milk per kilogram of DM intake), gross energetic efficiency (GEE, milk energy output/metabolisable energy (ME) intake) and efficiency of ME use for lactation (k _l, adjusted to zero energy balance). There were no interactions between factors. FCE and GEE were not different between diets, but supplemented cows had a lower (p < 0.01) k _l value (0.62) than unsupplemented cows (0.67), suggesting a diverted partition of nutrients towards body tissue. Mature cows were more efficient (p < 0.001) than young cows in terms of FCE (1.13 vs 0.87) and GEE (0.34 vs 0.26), but equal in terms of k _l (0.65). FCE (1.10 vs 0.90) and GEE (0.34 vs 0.27) were both higher on day 21 compared with day 84 post-calving, with a trend for a higher k _l in early lactation. Dual-purpose cows used tropical grasses efficiently for milk synthesis, and higher milk yield observed in supplemented cows was due to a higher intake of nutrients rather than a higher energetic efficiency.     

Vegetation-type effects on performance and meat quality of growing Engadine and Valaisian Black Nose sheep grazing alpine pastures

Lambs of two Swiss mountain breeds, Engadine Sheep (ES; n=55) and Valaisian Black Nose Sheep (VS; n=55), were fattened in 2010 and 2011 on one lowland and three alpine pastures. Groups of six to seven lambs per breed were allocated to pastures of a size allowing ad libitum intake on the following four vegetation types: (i) species-poor and nutrient-rich lowland (400 m a.s.l.) ryegrass–clover ley on flat terrain (‘lowland-rich’); (ii) alpine, species-rich and nutrient-rich vegetation type on a flat terrain (1950 m; ‘alpine-rich’); (iii) alpine, species-rich vegetation type, moderate in nutrients on steep terrain (2150 m; ‘alpine-moderate’); and (iv) alpine, species-rich and nutrient-poor vegetation type on steep terrain (2150 m; ‘alpine-poor’). Lambs were slaughtered after 9 weeks of grazing in a commercial slaughterhouse. Carcasses were subjected to the Swiss CH-TAX classification grid. Meat quality was analysed on the Musculus longissimus dorsi (LD) in the segment of Musculus longissimus lumborum. Forage quality varied among vegetation types as anticipated. Across all sites, ES were superior (P<0.001) to VS in dressing percentage (43.9 vs. 38.4), carcass weight (18.4 vs. 16.4 kg), meat conformation and fat cover scores, even though daily gains had been lower (105 vs. 122 g/d; P<0.05). Meat of ES contained more dry matter, protein, total ash (P<0.001) and fat (P<0.05). Their meat was darker and more intensive red, had lower cooking losses (23.0 vs. 25.1%) but was less tender (65.6 vs. 58.1 N) compared to VS (P<0.001). Vegetation types offering good quality forage (lowland-rich and alpine-rich) enhanced average daily gains, dressing percentage, meat conformation and fat cover scores (mostly P<0.05 against alpine-moderate and -poor). Similarly, a higher vegetation quality promoted a higher intramuscular fat and lower cooking losses. Meat from lowland-rich was darkest and had the lowest shear force (P<0.05). Almost no breed×site interactions occurred in growth performance as well as carcass and meat quality. It was therefore concluded that both breeds are similarly well adapted to the extensive pasture production system in alpine regions. Still, ES seem to be the more efficient one of the two sheep breeds. The results also indicate that growth performance and meat quality clearly vary between vegetation types in animals grazing alpine pastures.     

云贵高原人工草地划区轮牧模式研究

根据云贵高原放牧人工草地初级生产特点,提出了无利用条件下牧草累积、草地净生长速率和草地现存量曲线拟合方案利用这些曲线方程确定放牧限度和预测放牧前后轮牧小区现存量,并制定在速生季短化牧和在缓生季长周期低频率轮牧的利用方案,对实例进行计算和分析,制定轮牧计划并提出改进建议。     

Implant and copper oxide needles for steers grazing Acremonium coenophialum-infected tall fescue pastures: effects on grazing and subsequent feedlot performance and serum constituents.

Two experiments were conducted to compare the effects of a progesterone-estradiol implant (PEI) with no implant (NI) and 20 g of copper oxide needles (CuON) with no CuON on grazing, subsequent feedlot performance, and selected serum constituents of steers. In Exp. 1, 114 Limousin crossbred yearling steers (317 kg average initial BW) were stocked continuously on Acremonium coenophialum-infected tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) pastures (C) or were rotated to bermuda grass (Cynodon dactylon [L.] Pers.) during summer months (R) of two consecutive years. Implant and copper treatments were applied within pasture. Blood samples were collected four times during each grazing season. Continuously stocked steers had greater (P less than .05) grazing gain, less (P less than .10) feedlot gain, and heavier (P less than .05) carcass weights than R steers did. Implanted steers had greater (P less than .05) pasture but lesser (P less than .05) feedlot gains than did NI steers. Prolactin concentrations were greater (P less than .05) from R than from C steers in late summer 1988. Ceruloplasmin was greater (P less than .01) with CuON than without on the last three and last two sampling dates in 1988 and 1989, respectively. In Exp. 2, blood samples were collected twice from 40 mixed-breed steers (283 kg average initial BW) receiving the same implant and copper treatments as in Exp. 1 and grazing infected fescue for one season. Serum ceruloplasmin and copper concentrations were increased (P less than .01) by CuON, but other measurements did not differ among treatments. Summer grazing of bermuda grass increased serum copper, ceruloplasmin, and prolactin but decreased grazing performance. Implanting increased grazing performance. Copper oxide needles increased serum ceruloplasmin and copper concentrations but did not affect steer performance.     

Heat energy for growing goats and sheep grazing different pastures in the summer.

Angora goat, Spanish goat, and Suffolk x Rambouillet sheep wethers (20 of each type; 30.4+/-.57, 31.3+/-.93, and 32.4+/-1.08 kg BW for Angora goats, Spanish goats, and sheep, respectively) were used to investigate influences of animal type and two grass-based pasture treatments on heat energy during summer grazing (mid-August through September in Oklahoma). The improved pasture treatment consisted of .7-ha paddocks primarily of Old World bluestem and johnsongrass, whereas the native pasture treatment entailed 10.8-ha paddocks dominated by big and little bluestems and indiangrass. Grasses were 95 to 100% of diets for the improved pasture treatment and 71 to 95% for the native pasture treatment; forbs were 2 to 25%, and shrubs were less than 4% of diets for the native pasture treatment. Metabolizable energy intake was similar (P > . 10) between pasture treatments but differed (P <.01) among animal types: 79, 99, and 113 kcal/(kg(.75) BW.d) for Angora goats, Spanish goats, and sheep, respectively; SE 7.1. Heat energy estimated via CO2 entry rate was affected by pasture treatment ( P = .08) and animal type (P < .001): improved pasture treatment 109, 132, and 151 kcal/(kg(.75) BW.d); native pasture treatment 126, 138, and 163 kcal/(kg(.75) BW.d) for Angora goats, Spanish goats, and sheep, respectively. Likewise, daylight grazing time was greater (P = .04) for the native than for the improved pasture treatment and differed (P < .01) among animal types: improved pasture treatment 5.3, 4.7, and 6.7 h; native pasture treatment 6.0, 5.7, and 8.1 h for Angora goats, Spanish goats, and sheep, respectively. In conclusion, heat energy during summer grazing of grass-based paddocks was less for goats than for sheep, and animal type can affect the increase in heat energy as energy intake and grazing time increase.