***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To evaluate the effects of length of exposure to prepartum transition diets on milk yield , fat and protein production . DESIGN Prospect i ve cohort study . The number of days that the cows were fed the prepartum transition diets was the exposure of interest . PROCEDURES Holstein and Holstein x Jersey cows ( n = 1008 ) were enrolled .  Diets given in the far-off dry period ( from end of lactation until approximately 3 weeks before expected parturition ) consisted of ad libitum access to perennial ryegrass pastures . Prepartum transition diets included perennial ryegrass pasture , ryegrass silage , cereal hay , grain , grain by-product , protein meals , BioChlor , sodium monensin , virginiamycin or tylosin , MgSO(4 ) , trace elements and vitamins . On a dry matter basis , these contained 16.0 % crude protein , 4.2 % rumen undegradable protein , and 9.9 mJ metabolisable energy/kg . Diets provided an estimated metabolisable protein balance of 286 g/day and dietary cation anion difference of -150 meq/kg dry matter . Statistical models controlled for effects of herd , calving day , breed , age and gestation period . RESULTS Increasing length of exposure to the prepartum transition diets significantly increased the 4.0 % fat- and 3.2 % protein-corrected milk yield and milk-protein yield as a linear and quadratic effect . The optimal duration of exposure to the prepartum transition diets was 25 days for fat- and protein-corrected milk production and 22 days for milk protein production . Milk-fat percentage decreased significantly and linearly with increasing exposure to the prepartum transition diets ; however , milk-fat yield or milk-protein percentage did not vary significantly with duration of exposure to the diets . CONCLUSIONS Increasing exposure to prepartum transition diets increased milk and milk-protein yields and decreased the milk fat-percentage , but not the milk-protein percentage or milk-fat yield CONTEXT Selective reporting of outcomes within published studies based on the nature or direction of their results has been widely suspected , but direct evidence of such bias is currently limited to case reports . OBJECTIVE To study empirically the extent and nature of outcome reporting bias in a cohort of r and omized trials . DESIGN Cohort study using protocol s and published reports of r and omized trials approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg , Denmark , in 1994 - 1995 . The number and characteristics of reported and unreported trial outcomes were recorded from protocol s , journal articles , and a survey of trialists . An outcome was considered incompletely reported if insufficient data were presented in the published articles for meta- analysis . Odds ratios relating the completeness of outcome reporting to statistical significance were calculated for each trial and then pooled to provide an overall estimate of bias . Protocol s and published articles were also compared to identify discrepancies in primary outcomes . MAIN OUTCOME MEASURES Completeness of reporting of efficacy and harm outcomes and of statistically significant vs nonsignificant outcomes ; consistency between primary outcomes defined in the most recent protocol s and those defined in published articles . RESULTS One hundred two trials with 122 published journal articles and 3736 outcomes were identified . Overall , 50 % of efficacy and 65 % of harm outcomes per trial were incompletely reported . Statistically significant outcomes had a higher odds of being fully reported compared with nonsignificant outcomes for both efficacy ( pooled odds ratio , 2.4 ; 95 % confidence interval [ CI ] , 1.4 - 4.0 ) and harm ( pooled odds ratio , 4.7 ; 95 % CI , 1.8 - 12.0 ) data . In comparing published articles with protocol s , 62 % of trials had at least 1 primary outcome that was changed , introduced , or omitted . Eighty-six percent of survey responders ( 42/49 ) denied the existence of unreported outcomes despite clear evidence to the contrary . CONCLUSIONS The reporting of trial outcomes is not only frequently incomplete but also biased and inconsistent with protocol s. Published articles , as well as review s that incorporate them , may therefore be unreliable and overestimate the benefits of an intervention . To ensure transparency , planned trials should be registered and protocol s should be made publicly available prior to trial completion Aspects of the metabolism and health of 63 cows which had been treated with different amounts of bovine somatotrophin ( BST ) daily in the preceding lactation and 25 control cows were studied . The aims of the study were first , to identify cows with ketotic conditions , either by measurements of blood metabolite concentrations or by clinical observations , secondly , to evaluate the risk of such conditions in cows treated with BST in the preceding lactation , and thirdly , to examine the metabolic and production consequences of the ketotic conditions in an environment in which the cows ' health , body condition and nutrition were closely observed . The cows were categorised objective ly by the use of cluster analysis into non-ketotic cows and ketonaemic cows , on the basis of their plasma metabolite concentrations . Twelve of the control cows and none of the cows previously treated with BST were classified as ketonaemic . Similarly , nine of the control cows but only two of the cows previously treated with BST had clinical ketosis . Some , but not all , of the decrease in the risk of clinical ketosis was attributable to the lower body condition score of the cows previously treated with BST . The clinical ly ketotic cows had a greater risk of other illness in the first 10 days post partum than their herdmates , but the ketonaemic cows had a significantly lower risk of other disease in the first 10 days post partum . The ketonaemic control cows were significantly heavier than the non-ketotic control cows , but they maintained a higher dry matter intake than the latter cows , probably a key factor in reducing the risk of clinical ketosis This cross-sectional survey examined the prevalence of ruminal acidosis and the effects of acidosis on the production of dairy cattle . Eight fresh cows , 3 primiparous and 5 multiparous ( < 100 d in milk ) , were selected r and omly from each of 100 dairy herds in 5 regions of Australia . Rumen fluid was obtained from each cow by rumenocentesis and a stomach tube , and sample s were tested for pH. Stomach tube rumen fluid sample s were analyzed for volatile fatty acid , ammonia , and D-lactate concentrations . On the basis of the results of all assays , cows were categorized into 3 distinct categories ( categories 1 , 2 , and 3 ) by cluster analysis . The percentages of cattle in categories 1 , 2 , and 3 were 10.2 , 29.9 , and 59.9 % , respectively . Mean rumen pH for categories 1 , 2 , and 3 were 5.74 + /- 0.47 , 6.18 + /- 0.44 , and 6.33 + /- 0.43 , respectively . Biochemically , categories 1 , 2 , and 3 were characterized , respectively , as follows : mean total VFA concentration ( mM ) , 100.74 + /- 23.22 , 94.79 + /- 18.13 , and 62.81 + /- 15.65 ; mean ammonia concentration ( mM ) , 2.46 + /- 2.02 , 7.79 + /- 3.75 , and 3.64 + /- 2.03 ; and mean D-lactate concentration ( mM ) , 0.34 + /- 0.86 , 0.28 + /- 0.97 , and 0.12 + /- 0.51 . Category 1 cows had higher propionate , valerate , isovalerate , and caproate concentrations and were of lower parity than cows in other categories . Cows in category 1 had higher milk production but lower milk fat content than category 2 cows . Herds were assigned to 1 of 3 groups according to the numbers of cows assigned to each category . Herds with > or = 3 of the 8 cows in category 1 were classified as acidotic . Herds with > or = 3 of the 8 cows in category 2 were classified as having suboptimal rumen function , and herds with > or = 3 of the 8 cows in category 3 were classified as normal . Herds that had 3 or more of the 8 cows in category 1 ( acidotic herds ) had diets with higher energy and nonfiber carbohydrate contents and a lower neutral detergent fiber content than herds with a high prevalence of category 2 or 3 cows . The lack of significance of a herd effect in the statistical models developed suggests that the categories were robust across production systems , in which diets varied from all pasture to total mixed rations . A point prevalence of 10 % ( 95 % credible interval , 8 to 12 % ) of cows with an acidotic profile indicates a high risk for acidosis in the cattle sample d. The higher nonfiber carbohydrate and lower neutral detergent fiber contents of diets for herds with a high prevalence of category 1 cows ( acidotic herds ) indicates that there may be opportunities to reduce the risk of acidosis by dietary manipulation OBJECTIVE To determine the effect of a controlled-release monensin capsule administered at cessation of lactation on incidence of calving-related disorders , fertility , and milk yield in dairy cows . ANIMALS 290 dairy cows treated with monensin and 290 untreated control cows . PROCEDURE Treated cows received a capsule that released monensin at 335 mg/d for 95 days . Incidence of calving-related disorders ; daily milk yield up to 20 days postpartum ; test-day milk yield , fat , protein , and mature-equivalent 305-day milk production ; and body condition score at calving were determined . Reproductive variables were conception rate at first service , pregnancy rate , and calving-to-conception interval . RESULTS Cows treated with monensin were 2.1 times as likely to develop dystocia and 0.8 times as likely to develop metritis as control cows . For milk yield , there was an interaction of treatment X time X parity . In multiparous cows , monensin significantly improved milk yield at test days 4 and 7 . In addition , monensin increased body condition score at calving . CONCLUSIONS AND CLINICAL RELEVANCE Despite increasing the likelihood of developing dystocia and metritis , administration of monensin improved the lactational performance of multiparous cows and may be a promising additive for use at the time of cessation of lactation Data from 1,010 lactating lactating , predominately component-fed Holstein cattle from 25 predominately tie-stall dairy farms in southwest Ontario were used to identify objective thresholds for defining hyperketonemia in lactating dairy cattle based on negative impacts on cow health , milk production , or both . Serum sample s obtained during wk 1 and 2 postpartum and analyzed for beta-hydroxybutyrate ( BHBA ) concentrations that were used in analysis . Data were time-ordered so that the serum sample s were obtained at least 1 d before the disease or milk recording events . Serum BHBA cutpoints were constructed at 200 micromol/L intervals between 600 and 2,000 micromol/L. Critical cutpoints for the health analysis were determined based on the threshold having the greatest sum of sensitivity and specificity for predicting the disease occurrence . For the production outcomes , models for first test day milk yield , milk fat , and milk protein percentage were constructed including covariates of parity , precalving body condition score , season of calving , test day linear score , and the r and om effect of herd . Each cutpoint was tested in these models to determine the threshold with the greatest impact and least risk of a type 1 error . Serum BHBA concentrations at or above 1,200 micromol/L in the first week following calving were associated with increased risks of subsequent displaced abomasum [ odds ratio ( OR ) = 2.60 ] and metritis ( OR = 3.35 ) , whereas the critical threshold of BHBA in wk 2 postpartum on the risk of abomasal displacement was > or=1,800 micromol/L ( OR = 6.22 ) . The best threshold for predicting subsequent risk of clinical ketosis from serum obtained during wk 1 and wk 2 postpartum was 1,400 micromol/L of BHBA ( OR = 4.25 and 5.98 , respectively ) . There was no association between clinical mastitis and elevated serum BHBA in wk 1 or 2 postpartum , and there was no association between wk 2 BHBA and risk of metritis . Greater serum BHBA measured during the first and second week postcalving were associated with less milk yield , greater milk fat percentage , and less milk protein percentage on the first Dairy Herd Improvement test day of lactation . Impacts on first Dairy Herd Improvement test milk yield began at BHBA > or=1,200 micromol/L for wk 1 sample s and > or=1,400 micromol/L for wk 2 sample s. The greatest impact on yield occurred at 1,400 micromol/L ( -1.88 kg/d ) and 2,000 micromol/L ( -3.3 kg/d ) for sera from the first and second week postcalving , respectively . Hyperketonemia can be defined at 1,400 micromol/L of BHBA and in the first 2 wk postpartum increases disease risk and results in substantial loss of milk yield in early lactation 
    Output:
    
Examples where meta-analyses have been repeated in animal science or veterinary medicine show good consistency in estimates of effect .