A survey was carried out in 2003 in 49 dairy herds to determine the overall and pathogen-specific prevalence of intramammary infection (IMI) in Dutch dairy herds, and to compare the distribution with four studies performed from 1973 to 1985 in The Netherlands. Herds were randomly selected stratified over the 12 Dutch provinces, had at least 40 lactating cows and participated in the Dutch milk recording system. Quarter milk samples were collected from all 408 cows with a somatic cell count (SCC) ⩾250 000 cells/ml and 145 heifers with SCC ⩾150 000 cells/ml at the last milk test before the farm visit. Additionally, samples were collected from 519 (approximately 25%) of the remaining low-SCC cows and heifers with a SCC at the last milk test before the farm visit of <250 000 and <150 000 cells/ml, respectively. Bacterial growth occurred in 37·3% of milk samples of high-SCC cows and in 21·1% of low-SCC cows. Coagulase-negative staphylococci (CNS) were the most frequently isolated group of bacteria (10·8% of quarters) and were found in all herds. Prevalence of Staphylococcus aureus IMI was lower in 2003 than in 1973, respectively 1·8% and 6·2% of quarters. Prevalence of Streptococcus uberis and Str. dysgalactiae IMI was almost the same in the five samplings during the 30-year period, at 1·1–1·7 and 0·9–1·5%, respectively. Str. agalactiae was not found in this study. Prevalence of CNS IMI was higher in lactating heifers, while prevalence of Str. uberis, Str. dysgalactiae and penicillin-resistant Staph. aureus IMI was higher in older cows. Because distribution of pathogens changes over time, herd-level samples for bacteriological culturing must be taken regularly to monitor udder health. Additionally, national mastitis prevalence studies give important information through monitoring the national udder health status.

A study was carried out to analyse the production and composition of milk from Malagueña goats of different genotypes for the content of αs1-casein. Twenty goats were used, half of them with a high (HG) and half with a low (LG) genetic capability for αs1-casein synthesis. Among the ten HG goats, seven had BB and three had AB genotypes, whereas there were seven EF and three FF genotypes among the LG goats. The goats were fed a diet differing in crude protein content, 136 and 177 g/kg dry matter for diet 1 (D1) and diet 2 (D2), respectively. For each genotype group, a trial was conducted, with each of the two diets in a two-period balanced change-over design, in which the milk production and composition were analysed. The genotype was found to determine milk composition, with that produced by the HG goats being higher in total solids, protein, αs1-casein, αs2-casein and fat. Analysis of milk production values and, especially, those of the yields of the different components, revealed an interaction between the factors. HG goats that consumed D1 were more productive than LG goats, but this ceased to be so when the D1 diet was replaced by D2. However, LG goats, although less productive than HG ones when the D1 diet was consumed, showed increased productive capacity when D1 was replaced by D2. The main difference for the fatty acid profile of the dairy fat is that the milk fat produced by the HG goats contained higher levels of short and medium-chain fatty acids. From these results, it is concluded that, in terms of favouring production, the advantage of replacing animals with a low capacity for αs1-casein synthesis with those of a high capacity seems to depend on the protein level in the diet. Similarly, the advantage of changing to a diet of higher protein content depended on the animal's genotype.

Coagulase-negative staphylococci (CNS) have emerged as bovine mastitis pathogens in many countries. CNS mastitis is generally mild but can persist in the udder for long periods. Pathogenesis of CNS intramammary infection is not well understood. In the present study, adhesion, invasion and intracellular replication of twenty-two CNS strains isolated from bovine mastitis and the effect of bovine lactoferrin (bLf) on the internalization were studied in vitro in a bovine mammary epithelial (BME) cell model. The CNS strains were of Staphylococcus chromogenes, Staph. simulans, Staph. epidermidis, Staph. haemolyticus and Staph. cohnii urealyticus; two strains of Staph. aureus were used as controls. Seven of the CNS strains originated from persistent and five from transient mastitis infections. The in-vitro susceptibility of the strains to bLf was also investigated. All CNS species examined had an adhesive ability equal to that of Staph. aureus, but internalization varied among staphylococcal strains. The antagonistic effect of bLf on the adhesion and invasion of CNS strains was weak, but bLf significantly decreased intracellular replication and replication rates of CNS. No correlation between the in-vitro susceptibility of the strain to bLf or internalization among clinical signs of mastitis was established. No difference between the persistent and transient CNS strains in adhesion, invasion or replication rate was recorded. This in-vitro BME cell model can be used to study the virulence potential of mastitis pathogens, although the severity and persistence of eventual infections shall be further investigated in vivo. The role of bLf in intramammary infection caused by CNS may be limited.

Unsupplemented acid goat whey containing 0·96% protein and 2·76% lactose was fermented aerobically with 32 microflora extracted from various raw milk cheeses and dairy products. These microflora were screened for their ability to hydrolyse whey proteins (α-lactalbumin and/or β-lactoglobulin) and to generate peptides inhibitors of Angiotensin I Converting Enzyme. Five microflora were able to degrade whey protein. The most efficient microflora was able to fully hydrolyse α-lactalbumin and to a lesser extend β-lactoglobulin. It was extracted from Bamalou des Pyrenées cheese. Micro-organisms involved consisted of yeast Kluyveromyces marxianus and lactobacillus Lactobacillus rhamnosus. Both were able to produce ACE inhibitory peptides after whey fermentation.

We investigated the anti-allergic effects of one strain (T120) of a lactic acid bacteria (LAB) isolated from Mongolian fermented milk using atopic dermatitis (AD) model mice (NC/Nga mice). Strain T120 has already been identified as Enterococcus faecium and shown to induce strong production of IL-12 (Kimura et al. 2006). In in vitro studies, strain T120 suppressed total IgE production and induced IL-12 and IFN-γ production by splenocytes of NC/Nga mice. The additional examination of various neutralization antibodies was performed to elucidate in detail the mechanism of depressed IgE production by strain T120. As a result, it became clear that IL-12 induced by strain T120 increased production of IFN-γ and total IgE production was mainly controlled by the IFN-γ. In order to define the cells which produce IL-12 powerfully by this strain, antigen-presenting cells (APCs) such as macrophages and dendritic cells (DCs) were removed from the splenocytes, and the reactivity of these cells to the strain was examined. Induction of IL-12 and IFN-γ by strain T120 became significantly very low by removal of APCs from splenocytes. Therefore, it was clear that strain T120 acted on APCs and induced production of IL-12. Further, this strain enhanced the production of IL-10 by splenocytes. In in vivo studies, intraperitoneal injection of strain T120 inhibited serum IgE elevation and atopic dermatitis symptoms in NC/Nga mice. These results suggest that an anti-allergic effect of strain T120 depends on the increased production of IL-12 by APCs activated by the strain and following the increased production of IFN-γ. Further, activation of regulatory T cells by strain T120 may inhibit atopic desease.

The objective was to determine the effects of supplementing the diet with fish oil during the peri-partum period on the immune competence and the pathophysiological response to a lipopolysaccharide-induced mastitis challenge. Multiparous Holstein cows (n=30) were completely randomized to one of two treatments at 3 weeks pre-partum. Treatments differed only in the source of supplemental lipid and included either Energy Booster® or fish oil. Treatment diets were fed from −21 d relative to expected date of parturition until 10 d post partum. Treatments were fed as a bolus prior to the a.m. feeding. The dose of lipid during the pre-partum period was 250 g/d, whereas the amount of lipid supplemented post partum was adjusted to the level of intake, approximately 0·92% of the previous day's dry matter intake. Ex-vivo analyses of immune competence were measured including the antimicrobial activity of whole blood against Escherichia coli, Salmonella typhimurium and Candida albicans as well as the production of interferon-γ by peripheral blood mononuclear cultures. At 7 days in milk cows were infused with 100 μg of Esch. coli lipopolysaccharide into one rear quarter. Supplementing fish oil increased plasma concentrations of eicosapentaenoic and docosahexaenoic acids, but had no affect on the proportions of arachidonic acid at calving. Fish oil did not influence the production of interferon-γ or the antimicrobial activity of whole blood against any of the microorganisms. Furthermore, fish oil had no ameliorative effect on either the local or the systemic acute phase response following an intramammary lipopolysaccharide challenge in early lactating Holstein cows. Supplementing fish oil in the diet of peri-partum cows will not protect them from deleterious effects of an excessive acute phase response.

The usefulness of the serum fructosamine (Fser) to monitor the retrospective glucose concentrations in transitional dairy cows (n=17) was evaluated. In weekly blood samples (3 weeks before to 5 weeks after calving) concentrations of plasma glucose and serum fructosamine, β-hydroxybutyrate (βOHB) and total proteins were determined. The observed Fser concentrations (271±55 mean value, range 152–423 μmol/l) were within the range reported in the literature, and showed a progressive and significant decrease after calving. Mean plasma glucose concentration was 60·6±5·0 (range 39·9–82·2) mg/dl increasing from week 3 before calving to the week of calving and then decreasing during the next 5 weeks of lactation. This decrease was coincident with inverse relationships between plasma glucose and milk yield (P=0·03) and serum βOHB (P<0·001). Linear regression analysis performed between serum fructosamine and (a) plasma glucose concentration of the same sampling and (b) plasma glucose concentration of 1, 2 and 3 weeks preceding the sampling, did not show significant and systematizing positive correlations. Persistent hypoproteinaemias that could affect the fructosamine concentrations were not found: mean value and range of serum proteins was 6·3±1·0 and 4·8–7·8 g/dl, respectively, and no correlation was found between serum proteins and Fser (P=0·26). Results did not support the possibility of retrospective monitoring of the plasma glucose concentration by serum fructosamine in dairy cows in the transition period.

Prevalence of mastitis pathogens in milk samples from dairy cows and heifers was studied over a period of 1 year (Aug 2005–Aug 2006) in ten dairy herds in Germany. Milk samples (n=8240) were collected from heifers without clinical mastitis at parturition (n=6915), from primiparous cows with clinical mastitis (n=751) and from older cows with clinical mastitis (n=574). Coagulase negative staphylococci (CNS) were the predominant group of bacteria isolated (46·8% of samples) from clinically healthy quarters of primiparous cows around parturition, followed by streptococci (12·6%), coliforms (4·7%) and Staphylococcus aureus (4·0%). Thirty-three percent of samples were negative on culture (range on farm level, 12·0–46·4%). In cases of clinical mastitis in primiparous and older cows, streptococci were the predominant finding (32·1 and 39·2%) followed by CNS (27·4 and 16·4%), coliforms (10·3 and 13·1%) and Staph. aureus (10·0 and 11·7%). Negative results were obtained from 21·3% (range, 0·0–30·6%) and 19·5% (range, 0·0–32·6%) of these samples. Results indicated substantial differences in the prevalence of pathogens among herds. There was a positive within-herd correlation between the monthly prevalences for Streptococcus dysgalactiae between the three groups of samples. This correlation was also found between clinical samples of primiparous and older cows for Staph. aureus. These correlations were not found for the other pathogens. Besides herd, prevalence of pathogens was influenced by parity, type of sample and season.

A multiplex PCR (mPCR) assay using previously known genetic markers of Shigella, Escherichia coli and Shiga-toxic Esch. coli was standardized. uidA gene was targeted for the common detection of Esch. coli and Shigella, whereas ipaH and stx1 genes were used as markers for the detection of Shigella and shiga-toxin producing strains, respectively. The standardized assays detected the target organism specifically and selectively. The mPCR developed by combining all the three reactions generated specific products. The inclusivity and exclusivity tests depicted the precise specificity of the mPCR assay. Results were interpreted on the basis of the pattern of amplicons generated: amplifications of the ipaH and uidA gene fragments indicated the presence of Shigella spp., amplification of uidA alone revealed the presence of Esch. coli and additional presence of verotoxin gene amplicon indicated verotoxinogenic nature of the strain. Specific patterns of bands were obtained when different strains of Esch. coli and Shigella spp. were subjected to this assay. The reactions, individually as well as in the mPCR, could detect approximately 1 cell per 20-μl PCR assay. The protocols were validated by analyzing the coded samples of full fat milk spiked with different pathogens. In naturally contaminated raw milk samples (n=100), Esch. coli were detected in all samples and verotoxinogenic Esch. coli in 15 samples. Shigella, however, was not detected in any of the samples. When DNA purified from the samples found positive for Shiga-toxic Esch. coli was directly used as template for the mPCR, the results showed agreement with the enrichment based detection. The mPCR assay, standardized in this study, may be used for rapid microbiological evaluation of milk samples. Further, the study emphasizes the need for better hygienic conditions in dairies.

The somatic cell count (SCC) in bovine bulk tank milk is presently used as an indicator of raw milk quality, reflecting the udder health status of the herd. During mastitis, SCC increases, mostly owing to an influx of polymorphonuclear leucocytes (PMN) from blood into milk, with a concomitant change in milk composition. Bulk tank milk samples were categorized according to their SCC, as well as polymorphonuclear leucocyte count (PMNC), to study relationships between SCC, PMNC and various raw milk quality traits, i.e. contents of total protein, whey protein, casein, fat and lactose, casein number, proteolysis and rheological properties. The proportion of PMN, obtained by direct microscopy, was significantly higher in samples with high SCC compared with low SCC samples. SCC and PMNC were strongly correlated, yielding a correlation coefficient of 0·85. High SCC samples had lower lactose and casein contents, lower casein number and more proteolysis than low SCC samples. Samples with high PMNC had a lower casein number than low PMNC samples. Samples with high and low SCC or PMNC did not differ in respect to rheological properties. Our results do not indicate that PMNC is a better biomarker than SCC for raw bulk tank milk quality, as previously proposed.

In goats, αs1-casein polymorphism is related to different rates of protein synthesis. Two genetic variants, A and F, have been identified as strong and weak alleles based on a production of 3·5 and 0·45 g/l of αs1-casein per allele. The aim of the trial was to test whether goats can select their diet as a function of their genetic aptitude to produce milk at different casein levels and whether this selection can influence milk production or composition. Two groups of 8 animals, homozygous for strong (AA) or weak (FF) alleles were housed in individual pens. Using a manger subdivided into five separate containers, the goats were offered daily for 3 weeks: 1·5 kg of alfalfa pelleted hay, 0·7 kg of whole barley, 0·7 kg of whole maize, 0·7 kg of whole faba bean and 0·7 kg of pelleted sunflower cake. Total dry matter intake was similar between groups and resulted in nutrient inputs much higher than requirements. On average, goats selected 86% of maize plus barley and only 46% of faba bean plus sunflower. Indeed, AA goats selected less faba bean compared with FF goats (37·2 v. 56·7% of the available amount; P=0·01); during week 2 and week 3 they significantly increased maize selection (respectively for week 2 and week 3: 94·9 and 99·1% v. 85·3 and 87·3%) thus increasing the ratio between the high-energy feeds and the high-protein feeds (2·41 v. 1·81, P=0·023). As for true protein, the high soluble fraction (B1) and the indigestible fraction (C) were lower in the diet selected by AA goats (respectively in AA and FF groups: B1, 7·85 v. 9·23% CP, P<0·01; C, 6·07 v. 6·30% CP, P<0·001); these diet characteristics can be associated with lower losses of protein. Milk production, being similar in AA and FF groups when goats were fed with a mixed diet, significantly increased in AA group, when free-choice feeding was given (mean productions: 1198 v. 800 g/d, P<0·01). Casein content was higher in AA group than in FF group (2·70 v. 2·40%, P<0·01) whereas milk urea was higher in FF group (59·7 v. 48·8 mg/dl, P<0·01). In conclusion, when the animals were free to select their diet, their higher genetic aptitude to produce casein seemed to adjust their energy and protein dietary input in qualitative terms, thus leading to an increase in milk production and a decrease in milk urea. These results seem to demonstrate that interactions probably occurred between genetic polymorphism at the αs1-casein locus, diet selection and the efficiency of nutrient transformation into milk.

Bulk tank ewe's milks from Assaf, Castellana and Churra breeds categorized within three different Somatic Cell Count (SCC) groups (LSCC: <500 000; MSCC: 1 000 000 to 1 500 000; and HSCC: 2 500 000 to 3 000 000 cells ml−1) were used to investigate changes in capillary electrophoresis protein profiles and cheese-making properties. The results do not reveal a significant effect of SCC on total casein contents, because the sum of β-caseins decreased as SCC increased; no statistically significant differences were observed for the sum of α-caseins, and the values of κ-casein were higher in the HSCC milk. However, the soluble proteins other than α-lactalbumin and β-lactoglobulin increased with SCC. Regarding the effect of breed, the Assaf breed had the lowest contents of κ-CN, αs1-I-CN, αs1-II-CN 1-CN, αs1-III-CN, β1-CN and β2-CN. The protein profile was significantly correlated with curd textural properties. αs1-I-CN was the most influential variant because it was positively correlated with a large number of textural parameters. Cheese yield was positively correlated with all casein variants except αs1-III-CN, showing that the milk from local breeds were more suitable for cheese-making due to their higher contents of all the casein variants. Regarding curd texture properties LSCC milk curds showed more cohesiveness, associated with its lower content of αs1-III-CN and Castellana milk curds showed the highest values for firmness owing to their higher content of αs1-I-CN.

Lactobacillus fermentum CECT5716, a probiotic strain isolated from human milk, was characterized in a previous study. The objective of this study was to evaluate its sensitivity to antibiotics and its potential toxicity and translocation ability after oral administration to mice. For this puropose, 40 Balb/C mice were divided in two groups (n=20 per group). One group was treated orally with 1010 colony forming units (cfu)/mouse/day of Lb. fermentum CECT5716 during 28 d. The other group only received the excipient and was used as control. Food intake, body weight, bacterial translocation and different biochemical and haematological parameters were analysed. Oral administration of Lb. fermentum CECT5716 to mice had no adverse effects on mice. There were no significant differences in body weight or food intake between control and probiotic-treated mice. No bacteraemia was observed and there was no treatment-associated bacterial translocation to liver or spleen. Stress oxidative markers were not different in control and probiotic-treated mice. These results suggest that the strain Lb. fermentum CECT5716 is non-pathogenic for mice even in doses 10,000 times higher (expressed per kg of body weight) than those normally consumed by humans.

A questionnaire was sent to 2099 dairy farms to investigate the occurrence of poor milkability. Based on that, the frequency of poor milkability in Swiss dairy cows was 4% and the percentage of cows treated with oxytocin (OT) was 2%. In addition, 270 dairy farms that had reported cases of animals with poor milkability were contacted for an interview to classify the disorders. Farmers suspected disturbed milk ejection in 52%, anatomical dysfunction of the teat and/or the udder in 16% and milk ejection disorder or impaired milkability caused by discernable environmental factors in 32% of the cases. Forty-eight animals from 18 farms with suspected milk ejection disorders were selected for an experimental field study which included milk flow recording and OT administration to induce milk ejection. After cessation of the spontaneous milk flow, a low dose of OT (0·2, 0·5 or 1 i.u.) was injected i.v. to test the responsiveness of the udder to OT at a physiological level. When milk flow ceased again, 10 i.u. OT was injected i.v. (supraphysiological) to ensure complete udder emptying and to determine the residual milk. Milk ejection disorder could be confirmed in 69% of the cases, i.e. if residual milk was >20% of the total milk. Because in 27% of the animals milk ejection disorder was not confirmed on the basis of elevated residual milk, an anatomical disorder of the teat and/or the udder was suspected. Milk ejection disorder could be confirmed in 69% of the cases whereas in 27% of the suspected cases an anatomical disorder of the teat and/or the udder was suspected. An increased cortisol production in cows with milk ejection disorder was not obvious because faecal concentrations of cortisol metabolites with a 5β-androstane-3α,11oxo-structure were not augmented in animals with disturbed milk ejection.

The efficiency of Petrifilm™ AC (3M Microbiology, St. Paul, MN, USA) associated with the broths M17 and de Mann-Rogosa-Sharpe (MRS) at pH 5·4 was evaluated to enumerate Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus during the yogurt production. Commercial and reference strains of these microorganisms were experimentally inoculated in nonfat milk and incubated at 42°C for 4 h for yogurt production. At the moment of inoculation and after incubation, aliquots were collected, submitted to dilution using the broths M17 and MRS at pH 5·4, and plated for Strep. salivarius and Lb. bulgaricus enumeration according ISO 9232 and at Petrifilm™ AC plates, respectively. M17 plates were incubated at 42°C, and MRS plates were incubated at 35°C under anaerobiosis. After 48 h, the formed colonies were enumerated and the counts were compared by correlation and analysis of variance (P<0·05). In addition, colonies were randomly selected from all plates and characterized according to Gram staining and morphology. The obtained results indicated that Petrifilm™ AC plates associated to M17 and MRS at pH 5·4 can be considered as a suitable alternative for Strep. salivarius and Lb. bulgaricus enumeration during yogurt production, with slight interferences due to the acidity of MRS at the moment of inoculation, and due to the acidity of yogurt at the end of fermentation process. It was also observed that the MRS at pH 5·4 was not sufficiently selective for Lb. delbrueckii enumeration, despite it is indicated by the official protocol from ISO 9232.

This paper uses a Markov chain model to analyse the dynamics in farm-size distribution among the Flemish dairy sector and the impact of quota policy regulation on such changes. The model predicts a decline of 24% in number of farms in 2014 compared with the current situation with a more liberal exchange policy and a decline of 18% with a restricted quota exchange policy. From these Markov chain model results, we analysed the impact of farm-size distribution on eight different milk quality parameters (total bacterial count, somatic cell count, coliform count, freezing point, urea-N, fat content and protein content and penalty-points). In general, larger farms produce higher quality milk than smaller farms, especially with respect to the microbiological parameters (total bacterial count, somatic cell count and coliform count). The change in farm-size distribution from a liberal quota exchange policy would decrease the average total bacterial count by 18·0%, the somatic cell count by 2·1% and the coliform count by 11·0%. The aggregate performance of the other parameters are smaller with improvements in all cases of <1%.

Plant oils in the diet are known to alter milk fat composition owing to changes in the supply of fatty acid precursors and/or activity of lipogenic enzymes in the mammary gland. Thirteen mid-lactating Alpine goats were used in a 3×3 Latin square design with 28-d periods to evaluate possible mechanisms regulating milk fat synthesis and fatty acid composition on grass hay-based diets containing none (H) or 55 g/kg diet dry matter of sunflower-seed oil (HSO) or linseed oil (HLO). Inclusion of oils in the diet had no effect on milk yield but enhanced (P<0·05) milk fat secretion. Compared with the control, HLO and HSO decreased (P<0·05) C10–C16 secretion and increased (P<0·05) C18 output in milk, responses that were accompanied by reductions in milk fat cis-9 14:1/14:0, cis-9 18:1/18:0 and cis-9, trans-11 18:2/cis-9 18:1 concentration ratios. Plant oil supplements decreased (P<0·05) mammary stearoyl-CoA desaturase (SCD) activity but had no effect on SCD mRNA. Treatments had no effect on glucose-6-phosphate dehydrogenase, malic enzyme and glycerol-3-phosphate dehydrogenase activity, or mRNA abundance and/or activity of lipoprotein lipase, acetyl-CoA carboxylase and fatty acid synthase in mammary, hepatic or adipose tissue. The results provided little support for milk fatty acid secretion responses to HLO and HSO being mediated via changes in mammary, hepatic or adipose mRNA abundance or in the activity of key lipogenic enzymes. In conclusion, plant oils in the diet enhance milk fat synthesis, alter milk fatty acid composition and specifically inhibit mammary SCD activity in the goat. Furthermore, the results suggest that the regulation of mammary lipogenesis in response to plant oils appears related to factors other than altered mammary gene expression or potential lipogenic enzyme activity.

The objective of this study was to develop a mathematical model that accurately describes the rise and decline in plasma progesterone concentrations, and is able to define parameters describing progesterone appearance and disappearance during the bovine oestrous cycle. Daily plasma progesterone data from 27 cows were used to develop a compartmental model consisting of an appearance function and an appearance modulating function. Model outputs included an apparent appearance or secretion duration, appearance rate and an average disappearance rate (expressed as arbitrary units per day; units/d). Shape-based clustering identified three common shape-based groups (or clusters) of progesterone profiles defined as either ‘peaked’ profile, with the profile reaching a distinguishable peak, 'structured', with the profile exhibiting a wave-like pattern, or ‘flat top’, with the profile reaching a plateau. Differences in the model parameters for the three different shapes of progesterone profiles were examined: peaked (n=13), flat top (n=7) and structured (n=7). The mean duration of apparent appearance was 11·49 (sd 0·17 d) for all 27 profiles. The model estimates for total appearance of progesterone (area under the curve; ng/ml per cycle), mean appearance rate and maximum appearance rate were 69·04 ng/ml per cycle (sd 15·2 ng/ml per cycle), 3·19 ng/ml per cycle (sd 0·7 ng/ml per d) and 6·70 ng/ml (sd 1·31 ng/ml), respectively. The average disappearance rate was 1·0 units/d (sd 0·04 units/d). The apparent appearance duration was greatest (P<0·01) in the flat top profiles (12·54, sd 0·41 d) followed by the structured (11·77, sd 0·66 d) and the peaked (10·80, sd 0·30 d) profiles. Total and mean progesterone appearance, maximum progesterone appearance rate, and the progesterone disappearance rates were not different between the profiles. The model successfully simulated all components of the progesterone profile and was able to define specific parameters of different shaped progesterone profiles. A simple model able to estimate parameters describing progesterone appearance and disappearance can be used to explore the relationships between profile shapes and reproductive outcomes.