Glass Bolus Research Articles

An intraruminal soluble glass bolus containing melatonin — a potential system for early lamb production

Seasonal changes in daylength (photoperiod) are effectively monitored by the eye transmitting a neural signal to the pineal gland which responds by secreting a hormone, melatonin, during the hours of darkness. Decreasing daylength is accompanied by an increase in the duration of melatonin secretion and stimulates breeding activity in sheep.It has been demonstrated that both timed (afternoon feeding and injection) and continuous (subcutaneous and vaginal implant) administration of supplementary melatonin to ewes in mid-summer mimics the effect of short or decreasing photoperiod and can advance the onset of breeding activity. Such treatments can also increase relative fecundity at early mating by phase-advancing the mid-breeding season peak in ovulation rate. As the U.K. is not sufficient in lamb production and bearing in mind the economic pressure for early lamb marketing, effective melatonin treatment offers considerable potential for commercial application.

The effect of a zinc, cobalt and selenium soluble glass bolus on immune function in Lambs

Trace element deficiencies are common in many countries and affect animal health, productivity and welfare. Trace elements that can be limiting in animal nutrition include copper, cobalt, selenium and zinc. Deficiency diseases may be manifested as a consequence of a single or a multiple element deficiency. Deficiency in any of the above trace elements can result in an increased disease susceptibility and a decreased immune function. A soluble glass bolus has been developed for the sustained release of zinc, cobalt and selenium to sheep, using the same technology as the commercially available copper, cobalt and selenium bolus (Cosecure). The aim of this experiment was to observe whether the trace elements released from the bolus would have an effect on the immune function of sheep, as measured by the humoral immune response to a novel antigen.

Effect of selenium in soluble glass bolus on selenium content of milk and blood of goats.

Soluble glass bolus (SGB) with selenium (Se) was administered intraruminally to Se-deficient Philippine does to determine its effect on milk Se and to correlate the Se contents of does' milk and blood of does and kids. Five months after the Se administration, the does in the treated group (n = 14) had higher (p < 0.01) Se content in their blood (62.2 vs 25.7 micrograms/L) and milk (5.1 vs 2.5 micrograms/L) than does in control group (n = 13). Consequently, the blood Se of the kids (n = 14) from the treated does was higher (p < 0.05) than those kids (n = 13) in the control group (28.0 vs 5.1 micrograms/L). Blood and milk Se of does and blood Se of their kids correlated (p < 0.01) with each other. The increased Se level of does' milk because of Se supplementation was not regarded as a health hazard to humans.

The development of a soluble glass bolus to deliver selenium and cobalt to sheep

Trace element deficiencies have been reported throughout the UK and are known to decrease the productivity and welfare of animals. Selenium deficiency is characterised by muscular myopathy, white muscle disease or stiff lamb disease. Subclinical deficiencies can also cause reduced growth rate and impaired immune function. In ruminant animals, cobalt is required for the synthesis of vitamin B12 and deficiency leads to Pine, characterised by emaciation, anaemia and listlessness. Trace element deficiencies can be due to either a single element or multiple elements. Situations occur particularly in sheep where cobalt and/or selenium are deficient but where copper supplementation can be toxic. To correct these deficiencies, a single long-lasting and effective treatment in the form of a soluble glass bolus has been designed to release cobalt and selenium. This new bolus is similar to the commercial Cosecure® bolus, which is a Co/Se/Cu soluble glass, in which zinc replaces the copper.

The development of a soluble glass bolus to deliver selenium and cobalt to sheep

Trace element deficiencies have been reported throughout the UK and are known to decrease the productivity and welfare of animals. Selenium deficiency is characterised by muscular myopathy, white muscle disease or stiff lamb disease. Subclinical deficiencies can also cause reduced growth rate and impaired immune function. In ruminant animals, cobalt is required for the synthesis of vitamin B12 and deficiency leads to Pine, characterised by emaciation, anaemia and listlessness. Trace element deficiencies can be due to either a single element or multiple elements. Situations occur particularly in sheep where cobalt and/or selenium are deficient but where copper supplementation can be toxic. To correct these deficiencies, a single long-lasting and effective treatment in the form of a soluble glass bolus has been designed to release cobalt and selenium. This new bolus is similar to the commercial Cosecure® bolus, which is a Co/Se/Cu soluble glass, in which zinc replaces the copper.

Ovine White-Liver Disease (OWLD). Trace Elements in Liver

Trace elements in liver were examined in vitamin B12 deficient lambs which developed ovine white-liver disease (OWLD), in cobalt/vitamin B12 supplemented lambs on the same pastures as well as clinically healthy, but sometimes subclinical B12 deficient lambs on other pastures (H). Liver Co was marginal to deficient in both OWLD lambs (S lambs) and H lambs. Supplementation with B12 or Co elevated liver Co. Liver copper was significantly lower in OWLD lambs than in the H lambs, and Co/B12 supplementation on pasture generally had no significant effect on the contents. Dosing lambs on OWLD pastures with copper oxide needles (SCuO), however, resulted in high/toxic liver Cu. Dosing with Co, Se and Cu glass boluses resulted in adequate liver Cu, except for 1 lamb with toxic amounts indicating dissolution and absorption of the bolus. OWLD lambs had significantly lower liver molybdenum than H lambs, and Co/B12 supplementation elevated values, while CuO treatment depressed them. Liver zinc, manganese and selenium are also reported.

Marginal deficiencies of cobalt and selenium in weaner sheep: response to supplementation

Five groups of 30 weaner wethers were given (i) no treatment, or a supplement of either (ii) copper (injection), (iii) cobalt (intraruminal pellet), (iv) selenium (intraruminal pellet) or (v) copper, cobalt plus selenium (intraruminal, soluble glass bolus). Liveweight, wool growth and indicators of copper, cobalt and selenium status were measured over a 54-week experimental period. The provision of all 3 elements resulted in a 180 g increase (P&lt;0.05) in clean wool growth relative to controls. With selenium or cobalt alone there was a trend towards increases in clean wool, whereas wool growth of copper treated sheep was identical to the controls. There were no persistent or significant treatment effects on liveweight. The results indicate that both wool and liveweight changes should be used to assess responses to trace elements and show that combined deficiencies, not detectable in experiments using single element supplements, may depress productivity in grazing sheep. Glass boluses were an effective method of providing selenium and raised selenium in liver and plasma for 54 weeks. Selenium pellets resulted in smaller, less persistent increases in these tissues. Glass boluses were less effective than cobalt pellets in providing cobalt and resulted in only a small increase in vitamin B12 at 26 weeks (P=0.1), compared with increases due to cobalt pellets at both 26 and 54 weeks (P&lt;0.05).

Use of a Soluble Glass Bolus for Supplementation of Copper and Selenium to Cows

Use of a Soluble Glass Bolus for Supplementation of Copper and Selenium to Cows

Use of intrarumlnal soluble glass boluses containing two levels of melatonin for early lamb production

It has been shown that giving mule ewes a soluble glass bolus which contained 150 rag melatonin on 2 July, advanced the onset of the oestrus cycle. This experiment was designed to investigate whether the dose rate of melatonin could be reduced.1.40 ewes not treated (control).2.40 ewes given glass bolus containing 150 mg melatonin.3.40 ewes given glass bolus containing 100 mg melatonin.120 mule ewes (Blue-faced Leicester x Swaledale) aged between 4 and 6 years all of proven breeding ability were divided into 3 similar groups by age, weight and body condition on 2 July. One group was left untreated and 2 groups received a polymer-bonded soluble phosphate glass bolus (Pilkingtons P.L.C.) which contained the appropriate level of melatonin (Sigma Chemicals Corporation). Each bolus was cylyndrical in shape measuring 1.8 cm in diameter and 3.0 cm in length. Tho average mass and specific gravity of boluses were 23 g and and 3.0 respectively.

The effect of soluble-glass boluses containing copper, cobalt and selenium on the blood composition of ewes

An experiment was carried out on a site where herbage selenium content is known to be low, to examine the value of soluble-glass boluses as a means of providing supplementary copper, cobalt and selenium to ewes. Sixty-one Welsh half-bred ewes were divided into two groups. Thirty ewes were given a single glass bolus and 31 were left as untreated controls. Measurements of plasma copper and caerulo-plasmin concentrations, serum vitamin B 12 concentration and erythrocyte glutathione peroxidase activity all showed significant increases owing to treatment with soluble-glass boluses. These glass boluses also gave protection to the foetus and the young lamb in its early life.

Plasma melatonin concentrations in ewes following administration of an intraruminal soluble glass/melatonin bolus

There is novel economic potential in the use of the pineal methoxyindole, melatonin, to alter the timing of oestrous activity in seasonally breeding farm animals, such as the sheep, to achieve premium 'out of season' market prices for the progeny. Melatonin interacts at the higher neural centres of the brain to regulate hypothalamic/pituitary events in seasonal reproductive function. A number of controlled release melatonin systems are currently under development, although the critical parameters of supplementary melatonin administration (plasma concentrations and exposure interval) are yet to be accurately defined. This study attempts to define such parameters with specific reference to an intraruminal soluble glass bolus system for melatonin delivery.

Use of an intraruminal soluble glass bolus containing melatonin for early lamb production.

The use of melatonin to advance the onset of seasonal oestrus is potentially useful for early lamb production. A number of delivery systems for melatonin have been developed and this study evaluates an intraruminal soluble glass bolus under field conditions. Anoestrous, non-lactating mule and Dorset cross mule ewes were treated in late June with two types of bolus of different solubilities (melatonin 1, 'slow release' and melatonin 2, 'extra slow release'). Rams were introduced in mid-August for a target lambing pattern in mid-January. The percentage pregnancy/lambing rates were 80/78, 97/92 and 100/100 in the control, melatonin 1 and melatonin 2 groups, respectively. The number of lambs born per ewe put to the ram was significantly increased by treatment with melatonin 2 (P less than 0.05) from 1.17 to 1.64 in the mule ewes and 1.64 to 1.72 in the Dorset cross mule ewes. The melatonin containing soluble glass bolus is a novel and convenient method of reducing the number of barren ewes in an early lambing flock.

An Assessment of the Performance of a New Formulation of Soluble Phosphate Glass Bolus on the Copper and Selenium Status of Scottish-Blackface Ewes

Soluble, phosphate glass boluses containing copper, cobalt and selenium have proved successful in elevating and maintaining blood levels of these trace minerals in sheep (Driver et al, 1985 &amp; 1986). In 1983 these boluses were marketed as the trace mineral supplement COSECURE. Recently trials with glasses of various solubilities were carried out and one formulation (Code EX) proved superior to all glasses tested to date (Driver et al, 1988). Last year the performance of this more soluble glass was compared with that of the commercial product, COSECURE, on a site which in previous years had shown severe copper deficiency.On day 0 (22 October), 20 Scottish-Blackface ewes each received one new (EX) bolus, another 20 received COSECURE boluses and a further 15 were left as untreated controls. Blood samples were taken at intervals over the following 330 days and assayed for plasma copper and serum caeruloplasmin for copper status and erythrocyte glutathione peroxidase (GSHPx) as a measure of selenium status. Boluses were recovered from culled ewes at 341 days after bolusing. The results were analysed by an analysis of variance.

Use of soluble glass rumen boluses to provide a supplement of copper for suckled calves

SummaryAn experiment was carried out on a site where the copper content of herbage was relatively low (4·7–6·2 mg/kg d.m.) to examine the value of copper contained in soluble glass rumen boluses as a means of providing supplementary copper to calves.Forty-five spring-born suckled calves (mean live weight 91 kg) were divided into three groups on the basis of body weight. Animals in group GB were given two boluses initially, those in group CI each received copper injections at approximately monthly intervals and those in group C remained as controls throughout. Group C calves became progressively hypocupraemic (minimum mean plasma copper 8·5 μmol/1) compared with those in groups GB and CI which showed an increase in plasma copper concentration. In addition measurements of plasma caeruloplasmin activity, blood haemoglobin concentration and erythrocyte superoxide dismutase activity all showed significant increases due to treatment. No response in live-weight gain was observed but overall live-weight gain was approximately 1·05 kg/day. Although the initial response in plasma copper was quicker with copper injections, measurements of erythrocyte superoxide dismutase activity and haemoglobin showed advantages of glass boluses not shared by copper injections. This possibly resulted from the slow release nature of copper in the glass. Under the conditions of the experiment where herbage molybdenum values were relatively low (1·2–1·9 mg/kg d.m.), copper contained in soluble glass boluses appeared to prevent hypocupraemia in calves as effectively as regular copper injections.

Use of soluble glass boluses containing Cu, Co and Se in the prevention of trace-element deficiencies in goats

SummaryTwo experiments were carried out to examine the value of copper, cobalt and selenium contained in soluble glass boluses as a means of providing supplementary trace elements to goats.In the first experiment 36 purebred Toggenburg goats were used and divided into two groups. One group was treated with soluble glass boluses while the other was left as control.In the second experiment 46 Saanen half-bred goats were used, divided into three groups. The first group was treated with soluble glass boluses, the second was treated with selenium injectable compound and the third was left as control.Blood samples were collected on four occasions, during an experimental period of almost 12 months and plasma copper, serum vitamin B12 and blood selenium concentrations were determined. All those measurements showed significant increases for about a year, and were due to treatment. The advantages of glass boluses were not shared by the selenium injectable compound.

Treatment of dairy sheep with soluble glass boluses containing copper, cobalt and selenium

The efficacy of soluble glass boluses in grazing dairy ewes was tested. Fifty-two Karagounico ewes were divided into two groups. The ewes of the first group were given a soluble glass bolus (COSECURE), containing copper, cobalt and selenium, while the ewes of the second group were left as controls. Blood and wool samples were taken prior to treatment, and subsequently at Days 103, 224 and 338 post-treatment. Blood samples were analysed for copper, selenium and vitamin B 12 concentrations, and wool samples only for copper concentration. The glass boluses released quantities of copper, cobalt and selenium sufficient to raise and maintain plasma copper, serum vitamin B 12, blood selenium and wool copper concentrations of treated ewes for about a year. Thus glass boluses appear to provide an efficient and practical method of supplying the three elements, involve the minimum amount of collection and handling of livestock, and cause no systemic toxicity and tissue damage to the animal.

Evaluation of the efficacy of trace element supplementation of an anthelmintic.

The efficacy of the selenium and cobalt contents of a trace element supplemented anthelmintic was evaluated in a series of trials with lambs in Scotland and Northern Ireland. The product was compared with other methods of supplementation and was found to be an adequate source of selenium when administered at monthly intervals. Its cobalt content was shown to be of some nutritional benefit on four of five sites but not as effective as the monthly 250 mg oral cobalt dose, vitamin B12 injection or intraruminal soluble glass bolus treatments also used. No growth responses were obtained and unsupplemented animals generally had an adequate cobalt and selenium status. No toxicity problems were encountered from either element.

COPPER AND SELENIUM SUPPLEMENTATION TO CALVES BY MEANS OF A SOLUBLE GLASS BOLUS

Two hundred and thirty-nine calves were used to assess the effectiveness of a commercial soluble glass bolus as an intraruminal supplement of copper and selenium. Administration of two boluses per animal raised serum selenium concentration from marginal to adequate but did not prevent the decrease of serum copper concentration from adequate to deficient in some calves over the summer. Key words: Copper, selenium, mineral supplementation, soluble glass, calves

Intraruminal soluble glass boluses containing melatonin can induce early onset of ovarian activity in ewes.

Soluble phosphate glass boluses (preparations A, B, and C) have been developed to release melatonin into the reticulo-rumen of ewes at relatively different (fast, medium or slow) rates. A fourth type (preparation D) containing no melatonin was used as a sham control. Four groups of seasonally anoestrous Suffolk-cross ewes were respectively dosed with preparations A, B, C or D on 4 July. Plasma samples were collected twice weekly for melatonin and progesterone assay. In Groups A, B and C, elevated daytime plasma concentrations of melatonin could be detected for about 5 weeks after bolus administration. However, the pattern of hormone release was variable between groups, with Group C animals maintaining higher plasma melatonin concentrations for a longer period. The control animals had undetectable daytime melatonin levels. The onset of cyclic ovarian activity in the animals treated with the 'slow' release bolus (Group C) was significantly (P less than 0.05) advanced compared to the control group. The 'fast' and 'medium' release treatments (Groups A and B) did not significantly alter the onset of ovarian activity. The results indicate the potential of a novel and convenient method of melatonin delivery for induction of early breeding activity in ewes.

The efficacy of soluble glass boluses (cosecure) in grazing cattle

Two soluble glass boluses (COSECURE) per animal were given to 19 (+ bolus), silage fed, growing cattle (160-350 kg) on April 16th 1984 (day 0). After 29 days these and 11 untreated (control) animals, matched for weight, breed and sex, were turned out on to a copper deficient upland pasture. On day 153 (Sept. 21) all the cattle were moved to a lowland pasture until day 196, when they were housed and fed silage.Blood samples and liveweights were taken on 5 occasions over 240 days. Copper status was assessed from plasma copper (Cu) and caeruloplasmin (CP) levels, and selenium status by erythrocyte glutathione peroxidase (GSHPx) activity.