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.     

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.     

甘肃马鹿冬季牧场牧草再生性对刈割的短期响应

在肃南裕固族自治县甘肃马鹿(Cervus elaphus kansuensis)不同放牧率(1.00、1.45、2.45、3.45、4.85、6.90AUM·hm-2)的冬季牧场,研究草原生产力与群落结构对牧草最佳生长期刈割的短期响应。结果表明,1)随放牧强度增加,刈割群落物种丰富度呈先增加后减少趋势,其中4.85 AUM·hm-2放牧率下的群落物种丰富度最高;刈割显著增加草地地上生物量。2)刈割群落的牧草株高和地上生物量均表现为超补偿生长,补偿指数分别以3.45、6.90AUM·hm-2放牧样地最高;各优势种变化趋势不同。3)刈割群落的Simpson优势度指数、Pielou均匀度指数在放牧较重样地最高;随放牧强度增加,群落Shannon-Wiener多样性指数呈先增加后减少趋势,以4.85 AUM·hm-2群落最高;且除4.85 AUM·hm-2群落外,刈割后的群落Shannon-Wiener多样性指数显著高于刈割前的(P0.05)。4)各功能群植物对不同放牧强度响应不同。因此,适宜放牧强度下,刈割能发挥草地最大生产潜力并维持群落结构稳定性。     

the utilization by sheep of winter and spring Smuts finger and Kikuyu pastures

Abstract

An experiment was conducted on Smuts finger (Digitaria eriantha ssp. eriantha) and Kikuyu (Pennisetum clandestinum) pastures during a winter and spring period to study the effect of postruminal energy and/or protein supplementation on the selection pattern and performance of sheep. In a further experiment the digestion and utilization of these pastures were quantified. Voluntary intake on both pastures was not significantly affected by postruminal addition of casein but glucose tended to depress intake. In vitro digestibility of organic matter (IVDOM) and crude protein content of oesophageal samples were not significantly influenced by either casein or glucose. Consequently, it was concluded that postruminal amino acid and energy supply do not alter the quality of pasture selection but, depending on circumstances, the amount eaten may be affected. The amount of non‐ammonia nitrogen (NAN) in winter and spring samples flowing through the abomasum was proportional to the nitrogen (N) content in the grass organic matter (OM), while the volatile fatty acid (VFA) production was approximately associated with the digestible OM (DOM) intake. N retention on Smuts finger was significantly higher than on Kikuyu. One of the reasons appears to be less unavailable N in the cell wall of Smuts finger than in the cell wall of kikuyu grass.     

Comparative long-term efficacy of ivermectin and moxidectin over winter in Canadian horses treated at removal from pastures for winter housing

The impact of a late fall treatment on the spring rise of fecal egg counts was evaluated in a controlled study with Canadian horses treated with 2 different dewormers immediately after removal from pasture for winter housing. The horses were stabled until the end of the trial period. Seventeen weanlings, 20 yearlings, and 15 2-year-old horses located in Ontario, which were presumed to be naturally infected with cyathostomins after pasture grazing, were randomly allocated to either a group treated with 0.4 mg/kg of moxidectin and 2.5 mg/kg of praziquantel or a group treated with 0.2 mg/kg of ivermectin and 1.5 mg/kg of praziquantel. Three weeks after treatment, all strongyle fecal egg counts were reduced to zero for both treatment groups. However, at 5 months post-treatment, mean geometric fecal egg counts were statistically higher for the yearlings and 2-year-old horses treated with ivermectin than for the yearlings and 2-year-old horses treated with moxidectin (P < 0.0001).     

Parasites in sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall region

Regular worm counts were done post-mortem on sheep that had grazed on Kikuyu pastures at the Elsenburg Research Station near Stellenbosch, a winter rainfall region. Major species were Trichostrongylus colubriformis, Trichostrongylus axei, while Ostertagia circumcincta was usually present in large numbers. Minor species were Haemonchus contortus, Nematodirus spathiger, Dictyocaulus filaria, Oesophagostomum venulosum, Trichuris spp., Chabertia ovina and larvae of the arthropod Oestrus ovis. Muellerius capillaris caused the formation of nodules in the lungs but were not counted. The trial started in April 1982 and was concluded in March 1984. One hundred and four sheep died or were slaughtered and 99 were examined post-mortem during this period. Total worm burdens rose to a peak of 88,763 (range 67,281-124,735) worms in March 1983, i.e. sheep mortality was such that the flock had to be treated with an anthelmintic in April 1983 to prevent further losses. Kikuyu pastures provide shade, form an excellent mat, the humus layer under the grass retains moisture and is an excellent incubator for preinfective larvae and a protector for infective larvae. If these qualities are combined with more than 100 mm of rain in spring and summer, Kikuyu pastures are a paradise for the free-living stages.     

Mefluidide treatment of tall fescue pastures: forage quality

Spring application of a plant growth regulator, mefluidide, to tall fescue (Festuca arundinacea Schreb.) pastures grazed from May to September reduced (P less than .05) available DM and digestible OM per hectare by 51 and 41%, respectively, compared to untreated pastures. However, seasonal averages for N, Ca and P content and in vitro OM disappearance (OMD) were greater (P less than .05) and NDF was lower (P less than .05) in tall fescue from mefluidide-treated pastures than in untreated pastures. Compared to hand-clipped samples, esophageal extrusa of tall fescue was 63% higher (P less than .05) in N (2.7 vs 1.7%) and 26% lower (P less than .05) in NDF (52.6 vs 69.9%) than hand-clipped tall fescue samples, regardless of treatment. Extrusa and hand-clipped herbage samples were similar (P greater than .10) in OMD during May and September, but OMD of extrusa was greater (P less than .05) during June, July and August compared to clipped samples. As a consequence of preventing stem elongation and seedhead formation earlier in the growing season, mefluidide treatment of tall fescue maintained forage quality at a higher level during midsummer.     

Tri-level surgical treatment of cervical spinal cord compression in a Thoroughbred yearling

A Thoroughbred yearling was presented with neurological, radiographic, and myelographic abnormalities consistent with cervical vertebral stenotic myelopathy. Surgical correction was performed by using ventral cervical interbody fusion at 3 intervertebral spaces. The patient recovered uneventfully from surgery. The neurological status remained unchanged initially; however, significant improvement was noted 37 weeks postoperatively.     

The effects of melatonin and light treatment on the reproductive performance of yearling Suffolk rams

The effects of melatonin and light treatments on the reproductive performance of yearling Suffolk rams was investigated. One group (group A, n = 5) remained in the local light environment (lat. 51 degrees 43'N). The other two groups (group B, n = 5; group C, n = 5) were given a priming period of long days [18 h light (L):6 h dark (D)] during 26 January-9 March. During 9 March-16 October, group B was exposed to short days (9L:15D) and group C was given melatonin implants (Regulin) at 5-weekly intervals. Testis diameter, sexual behaviour and semen quality were used to assess reproductive performance. The responses of groups B and C were similar and peak reproductive performance occurred in these groups significantly earlier than in group A. Peak performance was not maintained in groups B and C throughout the short day and melatonin treatment periods and this has been attributed to refractoriness. The response of group C clearly indicates that melatonin treatment may be considered as an alternative to photostimulation for the preparation of rams for out-of-season breeding.     

Clinical observations on ostertagiasis in yearling cattle

The growth of a New Zealand strain of M. ovipneumoniae in broth culture at 37°C was examined. In these conditions, the organism had a minimum division time of 1.7 hr and attained a maximum titre of about 2×10⁹ CFU/ml. Growth produced sufficient turbidity, particularly in shaking cultures, to allow this to be correlated with the viable count. The cultures died rapidly following the attainment of maximum titre.

Electron microscopic examination revealed a morphology typical of mycoplasmas, except that most organisms measured 400 to 700nm in diameter which is relatively large. The presence of dumb-bell-shaped forms, and the absence of filaments suggest that the organisms divide by binary fission.