Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: V: Mob and individual-hind risk factors associated with calf rearing to weaning

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. Both years combined, 3364 adult and 653 yearling hinds were diagnosed pregnant in June by ultrasound scanning and monitored for reproductive success up to weaning. At weaning, pre-rut at approximately 100 days after calving, udders were palpated or observed by the farmer and hinds were categorised as lactating (wet) indicating survival of calf, or not lactating (dry). Farm management practices during calving and early lactation were recorded. Analysis of risk factors associated with progeny survival was done using path analysis (separately for adult and yearling hinds). Adult hinds >3 years old at calving, conceiving before 1 May and having a body-condition score >2 in September had 2.8, 2.4 and 2.9 times significantly higher odds of rearing a calf to weaning than other hinds, respectively. Adult hinds had about 5 times lower odds of rearing a calf to weaning when they were mixed with mature stags during calving. When farmers visited calving paddocks and checked for calving problems, adult hinds had 1.7 times higher odds of rearing a calf to weaning. When the farmer entered calving paddocks at least every second time they observed the hinds, yearling hinds had a twice higher odds of rearing a calf up to weaning. Sunny weather and high maximum temperatures were positively and negatively associated, respectively, with the probability of an adult hind being in lactation at weaning.     

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: V. Mob and individual-hind risk factors associated with calf rearing to weaning

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. Both years combined, 3364 adult and 653 yearling hinds were diagnosed pregnant in June by ultrasound scanning and monitored for reproductive success up to weaning. At weaning, pre-rut at approximately 100 days after calving, udders were palpated or observed by the farmer and hinds were categorised as lactating (wet) indicating survival of calf, or not lactating (dry). Farm management practices during calving and early lactation were recorded. Analysis of risk factors associated with progeny survival was done using path analysis (separately for adult and yearling hinds). Adult hinds >3 years old at calving, conceiving before 1 May and having a body-condition score >2 in September had 2.8, 2.4 and 2.9 times significantly higher odds of rearing a calf to weaning than other hinds, respectively. Adult hinds had about 5 times lower odds of rearing a calf to weaning when they were mixed with mature stags during calving. When farmers visited calving paddocks and checked for calving problems, adult hinds had 1.7 times higher odds of rearing a calf to weaning. When the farmer entered calving paddocks at least every second time they observed the hinds, yearling hinds had a twice higher odds of rearing a calf up to weaning. Sunny weather and high maximum temperatures were positively and negatively associated, respectively, with the probability of an adult hind being in lactation at weaning.     

Disease and mortality on red deer farms in New Zealand

A longitudinal observational study of 15 red deer farms was carried out in New Zealand for two years from March 1992. The deer were monitored for performance and health problems, and farm management practices were recorded. Numbers at risk were 4,683 hind-years, 2,459 stag-years and 3,202 weaner-years. The numbers of primiparous and adult hinds at risk of losing their progeny by weaning were 653 and 3,364, respectively. Where possible, postmortem examinations were carried out, and organs were sampled for histological and microbiological investigation. Rates of mortality varied with season with most stag and hind deaths in winter and weaner deaths in autumn and winter. Overall mortality rates were 1.77, 2.60 and 5.87 per 100 deer-years for hinds, stags and weaners, respectively. Malignant catarrhal fever accounted for 0.53 stag and 0.17 hind deaths per 100 deer-years at risk Misadventure, including broken bones, accounted for 15.4 per cent of weaner mortalities, or 0.53 weaner mortalities per 100 weaner-three months in autumn. Yersiniosis was confirmed in 18.6 per cent of weaner deaths, or 1.09 weaners per 100 weaner-years during the first six months after weaning, but was also suspected but unconfirmed in a further 41 per cent of weaner mortalities. Overall, 17 per cent of yearling hinds, and 9.2 per cent of adult hinds lost their progeny between pregnancy diagnosis in June and weaning in March. One outbreak of osteochondrosis was recorded. Mortality rates varied between farms and many mortalities were preventable.     

Accuracy of pregnancy diagnosis and prediction of calving date in red deer using real-time ultrasound scanning

One hundred and sixty-two 18-month-old farmed red deer were used to test the accuracy of pregnancy detection and equations for predicting gestational age. Deer ranging from 30 to 110 days gestation were examined by rectal ultrasonography using a 5 MHz transducer while they were standing. Each scan was recorded on video tape for measurements of uterine diameter, amniotic sac diameters, crown-rump length, head length, head diameter, nose length, chest depth, chest width and placentome base-apex length and width. Fetal age was calculated from the mean of the age predictions derived from each dimension measured on individual deer, for 132 deer between 44 and 110 days gestation. All the hinds diagnosed as pregnant produced offspring, and all the hinds diagnosed as not pregnant failed to produce offspring. Between one and six fetal and uterine dimensions were measurable and the number measurable increased with fetal age. The mean error of calving date prediction in 132 deer was 0.97 days. The error of prediction when measurements were made between 44 and 60 days was 0.44 days, whereas between 61 and 80 days and between 81 and 110 days the errors were +0.95 and +4.72 days, respectively. The estimates of calving date were all within 13 days of the calving date.     

Effects of vaginal Brucella ovis infection of red deer hinds on reproductive performance, and venereal transmission to stags

AIMS: To investigate the effects of vaginal Brucella ovis infection on the reproductive performance of red deer (Cervus elaphus) hinds. To determine whether stags may become infected with B. ovis by venereal transmission from mating infected hinds. METHODS: Thirty mixed-age red deer hinds serologically negative for B. ovis antibodies were synchronised for oestrus on 22 March 2000. B. ovis was inoculated into the vagina of each hind at oestrus and again, 18 days later. At oestrus, hinds were randomly allocated to six groups, each joined with a 16 month-old red deer stag seronegative for B. ovis, for 55 days. Hinds were blood sampled and scanned for pregnancy using rectal ultrasonography at monthly intervals. Six pregnant and four non-pregnant hinds were slaughtered pre-calving and three hinds were slaughtered post-calving. Reproductive tracts and foetuses were examined grossly, histologically and microbiologically. Calves were identified and blood sampled within 3 days of birth. Hinds and calves were blood sampled in February and May 2001 and vaginal swabs were collected from hinds for B. ovis culture. Blood was collected from stags, 5 and 19 days after mating and semen was collected for B. ovis culture. The 17 remaining hinds were mated in 2001 to two mixed-age wapiti (Cervus canadensis) stags. Both stags were blood sampled after mating. Sera were tested in a B. ovis complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA). RESULTS: All 30 hinds developed B. ovis antibody levels, measurable using either the CFT or ELISA, but these did not remain elevated. There was no evidence of infection, either by gross pathology, histopathology or microbiological culture in the ten hinds or six foetuses slaughtered pre-calving. All remaining 20 hinds produced normal calves, 15 of which survived until weaning. Three hinds experienced dystocia and gave birth to dead calves and two calves died within 4 days of birth. One hind which had dystocia was euthanased. Samples from this hind and from 3/5 dead calves showed no evidence of B. ovis infection. B. ovis was cultured from the vagina of 1/19 hinds 48 weeks after inoculation, at which time B. ovis CFT and ELISA results for this hind were negative. Most calves had B. ovis serum antibodies at 1-3 days of age but levels were negligible when sampled at 10-15 weeks of age. Foetuses and dead calves were all seronegative. Three of the five red deer stags used for mating became infected with B. ovis. The two wapiti stags used to mate the remaining 17 hinds the following year remained seronegative. CONCLUSIONS: B. ovis is unlikely to have significant detrimental effects on the reproductive performance of red deer hinds. Venereal transmission via the vagina of hinds is a possible route of transmission between stags. It is possible that survival of the organism in the vagina of some hinds could create difficulties in disease control programmes. CLINICAL RELEVANCE: B. ovis infection of hinds at the time of mating is unlikely to cause significant reproductive losses. Venereal transmission of B. ovis between stags via the hinds may occur when groups of hinds are joined with more than one stag.     

Intra-uterine transmission of paratuberculosis (Johne's disease) in farmed red deer

AIM: To determine whether intra-uterine transmission of paratuberculosis (Johne's disease) occurs in farmed red deer (Cervus elaphus) in New Zealand. METHODS: On four different farms, nine late-stage pregnant hinds with Johne's disease were slaughtered and samples were taken from them and their 10 fetuses. Samples of the hepatic, ileocaecal and mesenteric lymph nodes and the posterior ileum were collected from the hinds. The lung, liver, spleen, jejunum and ileum from the fetuses were sampled, as were the placentomes. Blood samples were tested using the 'Paralisa' test, a modified immunoglobulin G1 (IgG1) enzyme-linked immunosorbent assay (ELISA). Tissue samples were cultured using the BACTEC system, and fixed samples were sectioned and histological slides examined. RESULTS: All nine hinds and 9/10 fetuses (one hind had twins) were culture-positive for Mycobacterium avium subsp paratuberculosis (M. ptb). Six hinds had gross lesions of Johne's disease, while all hinds had characteristic histopathological lesions affecting the ileum, ileocaecal valve and associated lymph nodes. The only histopathological change observed in the fetuses was some mild inflammation in the lungs of one individual. Acid fast organisms (AFOs) were seen in histological sections of the lymph nodes and ileum of six hinds, and none were seen in tissues from the fetuses. These six hinds were Paralisa-positive, whereas the remaining hinds and fetuses were serologically-negative. CONCLUSIONS: These results confirm that there is a high risk of transmission of M. ptb from clinically affected hinds to their fetuses during pregnancy. CLINICAL RELEVANCE: Johne's disease is an increasingly important disease responsible for deaths in young red deer. Recognising the influence of intra-uterine transmission on the spread of this disease may be an important step towards improved control of Johne's disease.     

Risk factors associated with reproductive performance in small-scale dairy farms in Mexico

Several studies suggest that reproductive performance in small-scale dairy farms is low reducing the farms’ profitability. Therefore, identifying risk factors associated with low reproductive performance is a key step to implement an improved reproductive management program. Accordingly, the aim of the present study was to identify the main risk factors affecting the reproductive performance of cows in small-scale dairy farms. Ninety-six dairy farms were incorporated into this study, and data from 1263 lactations were collected with different events as potential risk factors. Logistic regression models were used to assess the association (odds ratio, OR) and impact (population attributable fraction, PAF) between the potential risk factors and the reproductive variables. The main risk factors associated with assisted calving were male calf and primiparous cows (OR?=?1.7, PAF?=?0.315 and OR?=?1.5, PAF?=?0.131, respectively), while for retained fetal membranes (RFM) were assisted calving and abortion (OR?=?4.5, PAF?=?0.440 and OR?=?8.1, PAF?=?0.239, respectively). The main risk factors for days to first service over 70 days in milk were low body condition score at calving (BCS?≤?2.5) and primiparous cows (OR?=?2.2, PAF?=?0.285 and OR?=?1.4; PAF?=?0.096, respectively), while for days open over 110 days in milk were low BCS at calving (BCS?≤?2.5) and primiparous cows (OR?=?1.7, PAF?=?0.213 and OR?=?1.4; PAF?=?0.096, respectively) The main risk factor for non-pregnant cows at first service was RFM (OR?=?1.7; PAF?=?0.059). In conclusion, assisted calving, male calf, BCS?≤?2.5 and RFM were the main risk factors associated with reduced reproductive performance in small-scale dairy farms in tropical and subtropical regions of Mexico.

     

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: II. Risk factors for adult hind conception.

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. About 2600 adult hinds were individually monitored for reproductive success. After mating, hinds were pregnancy-tested by ultrasound and were classified as having conceived before 1 May, after 1 May or as being not pregnant. Risk factors potentially affecting the probability of conception before 1 May or of conception that year were investigated using path analysis. Final path diagrams were used to formulate a putative management strategy for farmers to achieve the desired reproductive performance from adult hinds. To achieve a high pregnancy rate early in the mating season, farmers should wean calves early, exclude hinds which failed to rear a calf to weaning and hinds with a body condition score < or = 2.0 at mating, join hinds early with one or more sire stags, use only experienced sires for mating, limit the hind: stag ratio, use at least one back-up sire after the peak of mating, keep mating mobs away from disturbance and avoid shifting or handling mating mobs. The farmer should choose paddocks with high green pasture allowance and grazed down to no less than 5 cm high.     

Influence of calf genotype on dam lactation and calf growth in farmed red deer (Cervus elaphus)

Multiparous red deer (Cervus elaphus scoticus) hinds (n=17) were either mated to a red deer stag or artificially inseminated with semen from a wapiti bull (C.e. nelsoni) to produce red deer or F₁ crossbred (C.e. scoticus × C.e. nelsoni) calves to test the hypotheses that (1) red deer hinds rearing crossbred calves will produce significantly more milk to support calf growth than hinds rearing red deer calves, and (2) hind live weight and body condition may suffer as a result. Hinds and calves were grazed on ryegrass and white clover pastures and supplemented with pasture silage and barley grain when pasture supply was inadequate. Calves were left with their mothers until 9–10 months of age when lactation had terminated naturally. Mean body condition score (BCS) loss was greater in hinds rearing F₁ calves than in hinds rearing red calves in the period from late gestation to mid-lactation (September–March, P<0.05). F₁ calves grew significantly faster than red deer calves and were heavier at all ages. From February onwards there was a consistent decline in milk intake, and by the latest measurement (22 July) milk production was negligible, and most hinds had ceased lactating. Milk intake by the F₁ calves was significantly greater until day 114, after which the measured milk intake was not significantly different. Pasture intake of the F₁ calves was significantly greater at day 114 but not at other times (P<0.05). The average hind pasture intake was also not significantly affected by calf genotype when adjusted for post calving hind live weight. The results support the hypothesis that a red deer hind rearing an F₁ calf produces significantly more milk than a hind rearing a red deer calf, suggesting that the growth of a red deer calf is limited by its milk demand rather than milk supply by the hind. The study also supported the second hypothesis. Hinds rearing F₁ calves exhibited greater losses of body condition score relative to the hinds rearing red deer calves, indicating that the hinds rearing F₁ calves were in a greater negative energy balance that hinds rearing red deer calves. This highlights the additional energetic demands on a hind from feeding an F₁ calf and in a farmed context the need to ensure that adequate nutrition is provided.     

Use of postpartum vaginoscopic (visual vaginal) examination of dairy cows for the diagnosis of endometritis and the association of endrometritis with reduced reproductive performance

OBJECTIVE: To assess the association between the findings from vaginoscopic examination of postpartum dairy cows with peripartum reproductive disease and their subsequent reproductive performance, and to determine the factors that might be associated with a positive vaginoscopic examination (VV). METHODS: Cows (n=1325) from 17 seasonal calving dairy herds were enrolled if they had been calved at least 7 days and had at least one of the following conditions that placed them at risk of endometritis: retained fetal membranes (RFM), dystocia, a dead calf, hypocalcaemia, twin birth, calving induction or an observed vulval discharge (VD). Examination was undertaken 28-37 days before mating start date (MSD) within each herd. All cows were body condition scored (BCS) and were VV scored on a scale of 0 (clear) to 3 (purulent). The uterus and ovaries were assessed by rectal palpation. RESULTS: Cows with a positive VV score (1-3) were less likely to conceive to first service and had a lower pregnancy proportion than cows that had a negative VV score (score 0). Mean MSD to conception interval was longer in VV-positive cows. A positive VV score was associated with a low BCS, primiparity, intrapelvic uterus, poor uterine tone, large uterus, RFM, VD, dystocia, dead calf and twins. CONCLUSION: In the present study a positive VV score was associated with reduced reproductive performance and was more common in primiparous and low BCS cows. Of the at-risk cows, those with RFM, VD, dystocia, dead calf or twins were more likely to have a positive VV score.     

Field evaluation of melatonin implants to advance the breeding season in 1-year-old farmed red deer hinds

The efficacy of controlled-release melatonin implants to advance the onset of the breeding season was assessed in 1-year-old red deer hinds on five commercial deer farms in various localities in the North Island of New Zealand. Between 44 and 60 hinds in each of six herds were equally divided among treatment and control groups at each site. Melatonin treatment commenced between 27 November and 16 December and was achieved by the subcutaneous administration of two 18 mg melatonin implants. Three doses were given at about 30 day intervals. Two adult stags for each hind group were treated with three 18 mg melatonin implants concurrently on either two or three occasions. On each property, treated and control hinds were joined as one herd to treated stags commencing 30 January-10 February and concluding 15 May-2 June. The hinds in the four experimental herds underwent rectal ultrasound examination May-June to estimate conception rate and foetal age. Calving dates, hind and calf mortalities, weaning weights, and the antler growth cycle and harvesting data were recorded. Overall, treatment with melatonin resulted in an average advance of the median calving date of 22 days (range 12-36 days) when compared with untreated controls in the same herds. Pregnancy rates were 91.3-100% in treated hinds and 63.6-100% in untreated hinds. There were no differences in calf mortality or calf sex ratio between treated and untreated groups. No hind deaths could be attributed to melatonin treatment. The weaning weights of calves were 5.68 kg and 4.43 kg heavier for the male and female offspring of treated hinds respectively, compared with those of control hinds. Treated stags commenced rutting behaviour earlier than normal and the antler casting and growth cycle was advanced. Treatment resulted in advancement of the seasonal pattern of coat changes in hinds and stags, but no untoward side effects of the melatonin treatments were observed.     

Seasonal changes in nutritional status and reproductive performance of Zebu cows kept under a traditional agro-pastoral system in Tanzania

The objectives of this study were to assess changes in nutritional status/body condition score, percentage pregnancy and calving rate in Zebu cows and to establish the relationship between body condition score loss and postpartum interval to resumption of ovarian activity. A total of 198 cows and postpubertal heifers of the Tanzanian Shorthorn Zebu kept under a traditional management system were randomly selected from 200 smallholder herds. Factors investigated during bi-weekly visits include body condition score (BCS), heart-girth circumference, milk yield and reproductive status of the animals, pregnancy/non-pregnancy and cyclicity/non-cyclicity. Local weather conditions and dates of occurrence of other reproductive events such as calving were also recorded. Calvings occurred all year round but with a strong seasonal distribution characterized by annual peaks observed between April and July. The annual calving pattern was closely related to rainfall, with peak precipitation occurring a few months before peak calving. The overall percentage pregnancy varied from 30% to 50% throughout the year. Postpartum cows exhibited minimum mean BCS and heart-girth circumference 12–14 weeks after calving, and cows with BCS loss >1 point exhibited the longest time interval from calving to onset of ovarian activity.     

Intra-uterine transmission of Mycobacterium avium subsp paratuberculosis in subclinically affected red deer (Cervus elaphus)

AIM: To determine the rate of transmission of Mycobacterium avium subsp paratuberculosis (M. ptb) from hind to fetus in utero, and the risk of transmission from dam to fawn via infected colostrum and milk in subclinically affected red deer hinds. METHODS: Hinds were sourced from farms in Otago or Southland and selected for the study if they were positive to the immunoglobulin G1 (IgG1) modified enzyme-linked immunosorbent assay (ELISA) (Paralisa) and exhibited no clinical signs of Johne's disease. The hinds (n=35) were sent to a deer slaughter premises (DSP; n=31) or were killed on-farm (n=4). All post-mortem samples were collected from the fetus first and then from the dam, taking care to avoid cross contamination between samples. Fresh samples (n=185) were collected for culture, and tissue samples (n=72) were collected from 24 hinds and their fetuses for histopathological examination. RESULTS: A total of 24/35 hinds selected were suitable for inclusion in the study. Eighteen of these pregnant hinds were culture-positive for M. ptb, and 14 of these had culture-positive fetuses, representing a transmission rate of 78% (95% confidence interval (CI) =0.58-0.98) from dam to fetus. Of the 16 mammary glands sampled, 11 (69%) were culture-positive for M. ptb while 12/15 (80%) mammary lymph nodes sampled were also culture-positive. CONCLUSIONS: This study demonstrated a high rate of transmission of M. ptb from dam to fetus in red deer, and a potential risk of transmission to fawns suckling from mothers that are subclinically affected with Johne's disease.     

Diagnosis of pregnancy and prediction of fetal age in red deer by real-time ultrasonic scanning

Sixteen pregnant red deer hinds were scanned using real-time ultra sound at regular intervals during the first 150 days of pregnancy. In the early stages of pregnancy, an intra-rectal linear array transducer was used but later in pregnancy the hinds were scanned externally with a sector scanner. Pregnancy was determined from 30 days of gestation by intra-rectal scanning, and from 50 days by external scanning. With advancing age the size of the fetus increased, and linear regressions of size on age gave residual standard deviations of 0.508 days for head diameter and 0.506 days for trunk diameter. It is concluded that this technique can be used to determine pregnancy with a high degree of accuracy from 30 days of gestation and to predict calving date from fetal measurements within the range 1.5 cm to 7 cm for head diameter or 0.5 cm to 8 cm for trunk diameter, corresponding to a fetal age range of 35 to 150 days.     

Milk production and composition in captive Iberian red deer (Cervus elaphus hispanicus): effect of birth date

This study describes milk production and milk composition of Iberian red deer (Cervus elaphus hispanicus) females (hinds) and the effect of calving date and BW change of hinds by milking over 34 wk. All hinds produced milk throughout the 34-wk study period, well over the standard lactation period. Total milk yield was 224.1 +/- 21.1 L, and daily production was 0.91 +/- 0.06 L. Milk yield decreased with lactation stage (P = 0.01) and the later a calf was born (P = 0.008), and it was greater in posterior quarters (P < 0.05). Milk yield was unaffected (P > 0.10) by side position or milking order of the udder. Milk production did not correlate with hind BW (P > 0.1). Hinds lost 4.4% BW during lactation (P < 0.001); losses increased the later a calf was born (P = 0.012). Iberian red deer milk had 11.5% fat, 7.6% protein, 5.9% lactose, and 26.7% DM. Stage of lactation affected fat (P < 0.001), protein (P = 0.002), DM (P < 0.001), and protein:fat ratio (P < 0.001), but not lactose (P > 0.1). These constituents became concentrated as lactation proceeded, and protein was substituted by fat. Calving date had a similar concentrating effect on fat (P < 0.001) and DM (P < 0.001), whereas it decreased lactose (P = 0.015) and protein (P = 0.002), thus producing a substitution of protein by fat (ratio of protein to fat, P < 0.001). Milking order of quarters or their position had no effect on milk composition (P > 0.10). Results suggest that milk production and milk energetic quality might increase by advancing calving date in red deer hinds.     

The association of ruminal pH and some metabolic parameters with conception rate at first artificial insemination in Thai dairy cows

The objective of this study was to determine the association of metabolic parameters and cow associated factors with the conception rate at first insemination (FCR) in Thai dairy cows. The investigation was performed with 529 lactations from 32 smallholder dairy farms. At 3–6 weeks after parturition, blood samples and ruminal fluid were collected. Body condition scores (BCS) of cows were scored 1 week before expected calving date and at blood sampling date. Ruminal pH was measured at 2–4 h after morning feeding in ruminal fluid collected by ruminocentesis. Serum beta-hydroxybutyrate and serum urea nitrogen were measured by kinetic enzyme method. Cows with first insemination (AI) between 41 and 114 days postpartum were identified after pregnancy diagnosis for FCR. Breed, parity, interval from calving to first AI, BCS before calving, BCS after calving, loss in BCS after calving, SBHB, SUN, ruminal pH, and postpartum problems were selected as independent variables for a model with FCR as a dependent variable. A multivariable logistic regression model was used with farm as a random effect. Overall FCR was 27.2 %. The FCR depended on interval from calving to first AI, BCS before calving, and ruminal pH. The FCR between 69 and 91 days postpartum was significantly highest (45 %). Before calving, a cow with high BCS (≥3.5) had significantly greater FCR than a cow with low BCS (≤3.25; P?<?0.01). An increased ruminal pH raised significantly FCR (OR?=?2.53; P?=?0.03).     

A cow‐level association of ruminal pH on body condition score,serum beta‐hydroxybutyrate and postpartum disorders in Thai dairy cattle

Subacute ruminal acidosis in dairy cows occurs when ruminal pH is below about 5.5. However, the exact threshold level of ruminal pH affecting cow health is still in debate. This investigation was carried out in 505 cows within 31 farms. The postpartum disorders, including dystocia, retained placenta, anestrus, cystic ovary, metritis, clinical mastitis and lameness, were analyzed. Ruminal pH, serum beta‐hydroxy butyrate (SBHB), serum urea nitrogen and body condition score (BCS) were measured once during the 3 to 6 weeks postpartum, while BCS was determined once more at 1 week before calving. Ruminal pH was determinded by ruminocentesis technique. The ruminal pH was evaluated to study the association with BCS, SBHB and postpartum disorders using linear regression in a generalized linear mixed model with farm as a random effect. The results show that low ruminal pH was associated with dystocia, metritis and lameness. Moreover, a low ruminal pH can be found in cows with a high loss of BCS after calving and also in cows with low SBHB postpartum. These findings confirmed the feasibility of the ruminocentesis technique and the association of low ruminal pH on various postpartum disorders at the individual cow level. However, the consequences of low ruminal pH on dairy cow health still needs more exploration for a better understanding of the physiological mechanisms.     

Changes in serum oestrone sulphate and progesterone levels of red deer hinds during pregnancy

Serum oestrone sulphate (E1S) and progesterone (P) levels were recorded from six red deer hinds throughout the first two-thirds of gestation. E1S was generally undetectable until 30 days post conception when levels rose, peaking between 60 and 80 days, and fell to lower values between 80 and 170 days post conception. P levels rose after conception and remained elevated for the remainder of the study. This study indicates that in general the presence of measurable E1S levels in serum of hinds is associated with pregnancy.