The inclusion of companion forages in the diet alongside perennial ryegrass increased dry matter intake and organic matter digestibility in sheep.

The inclusion of companion forages in the diet of ruminant animals is gaining popularity in temperate regions due to observed improvements in animal performance. The aim of this study was to assess the effect of diet type on DM intake (DMI) and organic matter digestibility (OMD) in sheep. Furthermore, the effect of sward type on diet nutritive quality was investigated. Five dietary treatments were investigated using a 5 × 5 Latin square design experiment: Perennial ryegrass (Lolium perenne L.; PRG) only or PRG plus white clover (Trifolium repens L.;PRG + WC), red clover (Trifolium pratense L.; PRG + RC), chicory (Chicorium intybus L.; PRG + Chic) or plantain (Plantago lanceolata L.; PRG + Plan) at a ratio of 75% PRG and 25% of the respective companion forage and 100% PRG for the grass only treatment on a DM basis. Twenty Belclare castrated male (wether) sheep were housed in metabolism crates across five feeding periods. Individual DMI and faecal output were recorded daily and digestibility parameters were subsequently calculated. Results show that the inclusion of any companion forage increased DMI (kg/day DM) which ranged from 1.55 ± 0.038 (PRG) to 1.76 ± 0.038 (PRG + Chic) (P < 0.001). The PRG + WC (825 ± 1.1), PRG + RC (823 ± 1.1) and PRG + Chic (826 ± 1.1) diets had a greater in vitro OMD (g/kg DM) when compared to PRG (819 ± 1.1) or PRG + Plan (816 ± 1.1) (P < 0.001). Furthermore, the PRG + Chic (830 ± 2.9) diet had a greater in vivo OMD (g/kg DM) (P < 0.01) when compared to the PRG, PRG + RC, and PRG + Plan diets. Regression analysis showed that in vitro estimates moderately reflected in vivo measurements (r2 = 0.61). The inclusion of any companion forage increased dietary CP content and reduced the proportion of NDF in the diet. Crude protein concentration increased by an average of 16.5 g/kg DM and NDF content was reduced by 25.3 g/kg DM, on average, with companion forage inclusion (P < 0.001). Results suggest that binary sward mixtures benefit pasture-based sheep production systems, boosting sward quality, aiding increased DM intakes of a more digestible diet in the summer period.

Retinopathy induced in mice by targeted disruption of the rhodopsin gene.

Retinitis pigmentosa (RP) represents the most common mendelian degenerative retinopathy of man, involving death of rod photoreceptors, cone cell degeneration, retinal vessel attenuation and pigmentary deposits. The patient experiences night blindness, usually followed by progressive loss of visual field. Genetic linkage between an autosomal dominant RP locus and rhodopsin, the photoreactive pigment of the rod cells, led to the identification of mutations within the rhodopsin gene in both dominant and recessive forms of RP. To better understand the functional and structural role of rhodopsin in the normal retina and in the pathogenesis of retinal disease, we generated mice carrying a targeted disruption of the rhodopsin gene. Rho-/- mice do not elaborate rod outer segments, losing their photoreceptors over 3 months. There is no rod ERG response in 8-week-old animals. Rho+/- animals retain the majority of their photoreceptors although the inner and outer segments of these cells display some structural disorganization, the outer segments becoming shorter in older mice. These animals should provide a useful genetic background on which to express other mutant opsin transgenes, as well as a model to assess the therapeutic potential of re-introducing functional rhodopsin genes into degenerating retinal tissues.

Bio-economic modelling of sheep meat production systems with varying flock litter size using field data.

Sheep meat producers derive the majority of income from sales of weaned lambs, determined by flock conception rates, litter size, and lamb survival. Field data from commercial flocks can inform sensitivity analyses of the effect of litter size on flock productivity, feed demand, and gross margin. This study adapted an established bio-economic model of a flock of breeding ewes informed by statistical relationships (from linear models) between flock litter size (lambs born per ewe lambing) and production factors (such as flock barren rate, litter birth type and lamb birth weight) identified using 156 145 animal records from the Irish national sheep breeding database. Sensitivity analyses were undertaken to investigate the effects of flock litter size on flock production, feed demand, and gross margin. Results showed that as flock litter size increased, the proportion of lambs born as multiples increased, with 14 % of lambs born as singles when flock litter size was 2.2 lambs born per ewe lambing. Flock gross margin increased from €2 205 to €7 730 as litter size increased from 1.0 to 2.0 lambs born per ewe lambing. As litter size increased from 1.0 to 2.2 lambs born per ewe lambing, flock gross margin increased linearly by, on average, €52 per 0.01 increase in litter size. At a litter size of > 2.2 lambs born per ewe lambing, flock gross margin increased on average €12 per 0.01 increase in litter size. At a litter size of 2.2 lambs born per ewe lambing, flock efficiency (at 65.0 kg of lamb weaned per ewe presented for breeding), weaning rate (at 1.5 lambs weaned per ewe presented for breeding; not including excess lambs from large litters sold within a week after birth and thus not weaned on-farm), and gross margin (at €8 500) began to plateau. The results indicate lower marginal returns in gross margin at very high flock litter size, due to the lower value of additional lambs born as triplets and quadruplets compared with single- and twin-born lambs. However, the diminishing economic returns occurred at higher flock litter size than are currently biologically achieved in most flocks. Quantification from this analysis demonstrates how the value of increasing the number of lambs born changes at very high flock litter size, which can inform the priorities and performance benchmarking for international sheep meat production industries.

Mean difference in live-weight per incremental difference in body condition score estimated in multiple sheep breeds and crossbreds.

Body condition score (BCS) is a subjective assessment of the proportion of body fat an animal possesses and is independent of frame size. There is a growing awareness of the importance of mature animal live-weight given its contribution to the overall costs of production of a sector. Because of the known relationship between BCS and live-weight, strategies to reduce live-weight could contribute to the favouring of animals with lesser body condition. The objective of the present study was to estimate the average difference in live-weight per incremental change in BCS, measured subjectively on a scale of 1 to 5. The data used consisted of 19 033 BCS and live-weight observations recorded on the same day from 7556 ewes on commercial and research flocks; the breeds represented included purebred Belclare (540 ewes), Charollais (1484 ewes), Suffolk (885 ewes), Texel (1695 ewes), Vendeen (140 ewes), as well as, crossbreds (2812 ewes). All associations were quantified using linear mixed models with the dependent variable of live-weight; ewe parity was included as a random effect. The independent variables were BCS, breed (n=6), stage of the inter-lambing interval (n=6; pregnancy, lambing, pre-weaning, at weaning, post-weaning and mating) and parity (1, 2, 3, 4 and 5+). In addition, two-way interactions were used to investigate whether the association between BCS and live-weight differed by parity, a period of the inter-lambing interval or breed. The association between BCS and live-weight differed by parity, by a period of the inter-lambing interval and by breed. Across all data, a one-unit difference in BCS was associated with 4.82 (SE=0.08) kg live-weight, but this differed by parity from 4.23 kg in parity 1 ewes to 5.82 kg in parity 5+ ewes. The correlation between BCS and live-weight across all data was 0.48 (0.47 when adjusted for nuisance factors in the statistical model), but this varied from 0.48 to 0.53 by parity, from 0.36 to 0.63 by stage of the inter-lambing interval and from 0.41 to 0.62 by breed. Results demonstrate that consideration should be taken of differences in BCS when comparing ewes on live-weight as differences in BCS contribute quite substantially to differences in live-weight; moreover, adjustments for differences in BCS should consider the population stratum, especially breed.

Effect of ewe prolificacy potential and stocking rate on ewe and lamb performance in a grass-based lamb production system.

The objective of the present study was to investigate the effect of ewe prolificacy potential (PP; predicted number of lambs born per ewe per year) as dictated by sire breed type, stocking rate (SR; ewes per ha), and their interaction on ewe and lamb performance in a temperate grass-based lamb production system. The study was a 2 × 3 factorial design, consisting of 2 differing ewe PP and 3 SR which included 180 medium prolificacy potential (MP- Suffolk-sired crossbred ewes) and 180 high prolificacy potential ewes (HP- Belclare-sired crossbred ewes) allocated to 1 of 3 ( = 60 ewes) SR: low (LSR; 10 ewes per ha), medium (MSR; 12 ewes per ha) or high (HSR: 14 ewes per ha). Each treatment was managed in a 5-paddock rotational grazing system for the duration of the study. Medium prolificacy ewes were consistently heavier ( < 0.001) compared to HP ewes, with HP ewes having a higher BCS at lambing and 6 wk post-lambing (PL; < 0.05). Low SR ewes had a higher BW ( < 0.05) and BCS ( < 0.05) at mating, 6 wk PL, and weaning relative to MSR and HSR ewes which did not differ from each other. Lambs born to MP ewes were heavier at birth and weaning ( < 0.001) and achieved a higher ADG from birth to weaning ( < 0.05). Ewe PP had no effect on lifetime ADG or d to slaughter (DTS) with HP lambs yielding a higher carcass weight ( < 0.001). Low SR and MSR lambs achieved higher ADG from birth to weaning ( < 0.001) and weaning weight ( < 0.001) relative to HSR lambs and did not differ from each other, while post-weaning and lifetime lamb ADG was highest at the LSR, intermediate at the MSR, and lowest at the HSR ( < 0.001). A ewe PP by SR interaction existed for DTS, with MP lambs at the LSR reaching slaughter weight earlier ( < 0.01) relative to HP lambs, while at the MSR and HSR, MP and HP lambs did not differ from each other. High PP ewes produced a higher average born ( < 0.001) and weaned litter size per ewe ( < 0.01), with live weight weaned per ha ( < 0.001) increasing as ewe PP and SR increased. Lambing difficulty, ewe mother ability and lamb viability did not differ by ewe PP or SR. In conclusion, the lack of interaction between ewe PP and SR on many key performance measures in this study demonstrates the potential to increase the live weight of lamb weaned per ha through the use of higher ewe PP and SR levels, with no effect of ewe PP on lifetime lamb performance even as SR increased, with reductions in lamb performance primarily occurring at the HSR.

Measures of lamb production efficiency in a temperate grass-based system differing in ewe prolificacy potential and stocking rate.

The objective of this study was to quantify the effects of ewe prolificacy potential (PP; predicted number of lambs born ewe yr), as dictated by sire breed type, and stocking rate (SR; ewes ha) on ewe production efficiency (kg lamb live weight weaned:kg ewe live weight mated), lamb growth, lamb carcass output, and dry matter (DM; kg) and energy (UFL; unit of energy kg DM) consumption (in the form of both grazed and conserved herbage, concentrate supplementation, and total) in a temperate grass-based lamb production system. The study was a 2 × 3 factorial design, consisting of 2 differing ewe prolificacy potentials (medium prolificacy [MP]-Suffolk-sired crossbred ewes and high prolificacy [HP]-Belclare-sired crossbred ewes) and 3 stocking rates: low (LSR; 10 ewes ha), medium (MSR; 12 ewes ha), and high (HSR: 14 ewes ha). Each treatment was managed in a 5-paddock rotational system for the duration of the study. The HP treatment weaned more lambs ewe and ha ( < 0.01), yielded a higher average daily live weight gain (ADG) ha ( < 0.001), produced an additional 50 kg of lamb carcass ha ( < 0.05), and required 13% less DM and UFL to produce a kg of lamb carcass ( < 0.001) compared to the MP treatment. High prolificacy potential ewes had a 4% higher production efficiency ( < 0.05) than MP ewes. Ewe prolificacy potential had no effect on the total quantity of DM and UFL consumed ewe and lamb unit ( > 0.05). Increasing stocking rate increased the number of lambs weaned ha ( < 0.001) and increased lifetime lamb ADG ha ( < 0.001). Lamb carcass output (kg) ha was highest at the HSR, intermediate at the MSR, and lowest at the LSR ( < 0.001). The quantity of DM and UFL consumed ewe and lamb unit and kg of lamb carcass produced ha increased as stocking rate increased ( < 0.001). In conclusion, results from this study demonstrate HP ewes to be more efficient in the production of lamb. Increasing stocking rate provides the opportunity to increase lamb carcass output ha; however, achieving this increase in output required additional DM and UFL ewe and lamb unit above 12 ewes ha.

Comparison of energy rationing systems for late gestation ewes: Impacts on ewe and lamb performance.

The objectives of this study were 1) to compare the effects of a ME () or a NE () system for rationing ewes during late gestation on ewe and progeny performance and 2) to investigate incremental increases in NE allocation above 100% of recommendation during late gestation on ewe and progeny performance. Fifty-two twin-bearing ewes ( = 13 per treatment) were rationed to either 100% of recommended ME requirements (100% ME) or 100, 110, or 120% of recommended NE requirements (100% NE, 110% NE, and 120% NE) from d 112 of gestation to parturition. Mean energy intake, measured as ME and NE, from Day 112 of gestation to parturition was higher in all NE treatments compared with 100% ME ewes ( = 0.01). Ewes offered the 3 NE treatments had a higher live weight at parturition compared with 100% ME ewes ( = 0.02), with 100% NE and 120% NE ewes still being heavier than 100% ME ewes at 35 d postpartum ( = 0.02). Increasing NE allowance resulted in a linear decrease in the level of BCS loss prepartum ( = 0.01) and a linear increase in the level of BCS loss postpartum ( = 0.01). There was no difference observed between any of the treatments in total colostrum produced to 18 h postpartum ( = 0.29) or in total colostrum intake to 18 h postpartum ( = 0.27). Increasing maternal NE allowance led to a linear increase in lamb serum IgG concentration at 24 h postpartum ( = 0.03). The estimated milk production of 120% NE ewes tended to be higher than all other treatments at wk 6 of lactation ( = 0.08). Colostral SFA levels from 100% ME ewes was lower than that of all 3 NE treatments ( = 0.01), and unsaturated fatty acid (UFA) levels in colostrum of the 100% ME ewes were lower than those of the 100% NE ewes ( = 0.01). Cumulative levels of milk SFA, UFA, and MUFA did not differ between treatments ( = 0.19). Lamb growth rates during the first 5 wk postpartum were unaffected by treatment ( = 0.18) as were days to slaughter ( = 0.34). It can be concluded that both ME and NE systems used in this study are appropriate for formulating ewe diets during late gestation. Increasing NE allocation above 100% altered the pattern of body reserve mobilization during late gestation and early lactation without observed variations in lamb performance during this time.

Blood pressure control of drug treated hypertension in 18 general practices.

This study examined the blood pressure (BP) control and number of drugs prescribed for a sample of hypertensive patients from 18 practices in Northeast England. Out of a total of 35,379 registered patients aged 40-69 years, 2995 (8.5%) were on treatment for hypertension. Data was abstracted from the practice records of a random sample of 691 patients. Using British Hypertension Society standards, BP control was optimal for systolic pressure (less than 160 mm Hg) in 469 (68%), and for diastolic pressure (less than 90 mm Hg) in 345 (50%), but only 269 (39%) had optimally controlled systolic and diastolic pressures. Sixty-one per cent were taking one drug and 39% two or more; 82% of patients aged 40-49 years but only 61% of those aged 60-69 years had optimally controlled systolic pressures. Forty-three per cent of the 40 to 49-year-old group and 56% of the 60 to 69-year-old group had optimally controlled diastolic pressures. A strong inverse relationship was found between age and systolic BP control but there was no association between age and diastolic pressure or the number of drugs being prescribed. Sub-optimal BP control is a major problem and remedial strategies should stress the greater gain from treating older patients.

Stopping drug treatment of hypertension: experience in 18 British general practices.

BACKGROUND: Of the many reports published describing the effect of withdrawing antihypertensive medication from patients who have well-controlled blood pressure, none have been major British general practice studies. Studies from other settings have shown that a substantial minority can do so without harm or resulting in the relapse of their hypertension. AIM: To determine the proportion of hypertensive patients who could have their medication withdrawn without relapse, and to seek factors associated with success at withdrawal. METHOD: A longitudinal observational study in 18 general practices in north-east England. Practices selected and managed patients to guidelines suggested by the study protocol. Data were abstracted from records by practice staff over three years of follow-up. RESULTS: A total of 196 out of 224 (88%) patients were followed up. Forty-three (22%) of these 196 remained normotensive off medication for the whole study. A total of 108 (55%) of the 196 had restarted medication by three months. Twenty-six (31%) of the 84 males, but only 17 (15%) of the 112 females, remained off medication. No differences in age, morbidity, symptoms, or biochemical parameters occurred between the group who stayed off medication and those who restarted it. Apart from male sex, no factors were found that enabled the prediction of patients more likely to succeed at stopping medication. CONCLUSIONS: One-fifth of well-controlled hypertensives in British primary health care could have their medication withdrawn without the relapse of their hypertension or any harm. Of those that do relapse, over half are likely to have done so before three months. Life-long observation of all patients is essential.

Common pediatric dental problems.

Physicians who provide primary care for children have a unique position to provide diagnostic, triage, educational, and preventive dental care for patients. Several papers have been published regarding primary pediatricians' participation in the preventive dental health care of their patients. One publication, a survey of physicians in Alabama focusing on physicians' overall awareness of dental issues, concluded that most physicians believe they have a role in the oral health of their patients, yet most were not aware of the American Academy of Pediatric Dentistry's recommendations. Most physicians report that they routinely perform oral examinations during physical examinations of children and deliver preventive, oral information by the age of 6 months or earlier; however, most recommend that infants' first visit should be at 3 years of age, not at the time of first-tooth eruption as the authors recommend. Furthermore, many primary care physicians do not talk about oral health during prenatal counseling. Many physicians understand the preventive advantages of fluoride, yet most do not prescribe vitamin combinations that contain fluoride. If an understanding of the aforementioned issues of dental care, as well as aspects of preventive care in infants and children, become more uniform among primary care physicians, the prevention-based practice of pediatric dentistry will become much more successful, and children and adults will enjoy better dental health.

Audit of practice based cervical smear programme: completion of the cycle.

OBJECTIVES: To determine the effectiveness of a practice based cervical screening programme and the changing pattern of abnormal smear results and to improve the quality of care provided for patients. DESIGN: Audit of practice held data on cervical screening from 1980 to 1990. Changes in the programme were made after analysis of first five years' data. SETTING: Mixed urban and rural practice of 10,900 patients in Northumberland. SUBJECTS: Women aged 20-65 who had not had a hysterectomy. RESULTS: 2356 (85.1%) of the 2767 targeted women had a test during 1980-5 and 2498 (89.5%) of the 2790 women had a test during 1985-90. Inviting women aged 20-25 to attend for a test increased coverage from 45.8% (146/319) in 1980-5 to 82.5% (282/342) in 1985-90. The proportion of women with abnormalities requiring hospital referral rose in the second half of the study, especially among younger women (from 17/39 (44%) to 45/64 (70%) in women aged 25-34). CONCLUSIONS: Practice based cervical screening programmes can be highly effective. Cytological abnormalities affect patients psychologically as well as physically and practices should provide support and explanation for patients with abnormal results. Data from individual practices should be aggregated to allow health authorities to plan secondary care effectively.

Management of nursing services: financial control of establishments.

After restructuring budgetary responsibility for nursing services will be pushed down to unit level. Peter Creighton, area nurse (service and capital planning), Redbridge and Waltham Forest AHA, draws attention to the problems created by special duty payments.

Visualization of pig sperm chromosomes by in-vitro penetration of zona-free hamster ova.

Zona-free hamster eggs were penetrated by pig spermatozoa capacitated using bovine follicular fluid and Percoll gradients. A mean penetration rate of 80.1% was obtained from 5 ejaculates from 2 boars. Penetrated eggs were cultured and analysable metaphase chromosome spreads were obtained from 16.8%. The analysis of 20 pig sperm complements indicated that 9 were 19, Y, 10 were 19, X and 1 appeared to have an XY sex chromosome constitution.

Mapping of bovine markers CYP21, PRL, and BOLA DRBP1 by genetic linkage analysis in reference pedigrees.

We have analyzed DNA from 13 bovine reference pedigrees using primers specific for microsatellite markers derived from the 21-steroid hydroxylase (CYP21) and prolactin (PRL) genes and the leukocyte antigen (BOLA DRBP1) pseudogene. Linkage was demonstrated between PRL and BOLA DRBP1 (theta = 0.05; Z = 19.6), cyp21 and PRL (theta = 0.13; Z = 6.8), and BOLA DRBP1 and CYP21 (theta = 0.17; Z = 10.4). These results suggest an order BOLA DRBP1-PRL-CYP21, although in a multilocus analysis the alternative order PRL-BOLA DRBP1-CYP21 was also possible. The data confirm and extend the previously established syntenic relationship between these markers on bovine chromosome 23 and provide points of anchorage for further linkage studies in the reference pedigrees described.