Prevalence and incidence of intramammary infections in lactating dairy goats

AIM: To determine the prevalence of intramammary infection (IMI) of lactating dairy goats between 0 and 4 days postpartum, the prevalence and incidence rate of new IMI at Weeks 2, 14 and 27 of lactation, and the relationship between herd-level prevalence of IMI and bulk tank somatic cell count (BTSCC).

METHODS: Milk samples were collected from 8% of a herd (total 624 does) from 18 dairy goat herds in the Waikato region of New Zealand, for bacteriology and somatic cell count (SCC) determination, from both glands within 4 days of kidding (Week 0) and again at Weeks 2, 14 and 27. Prevalence of IMI was determined at each time point and incidence rate calculated for Weeks 0–2, 2–14, and 14–27. Greenwood and Reed-Frost models were compared for estimation of the transmission parameter for all pathogens, and for Staphylococcus aureus, coagulase negative staphylococci (CNS) and Corynebacterium spp. separately.

RESULTS: Bacteria were isolated from 1,122/4,814 (23.3%) glands, with CNS (13.4%) and Corynebacterium spp. (7.3%) being the most common isolates. Prevalence of any IMI increased with stage of lactation, varied among herds, and increased with age (all p<0.05). Incidence rate was 80, 24 and 7 new IMI/10,000 gland days for Weeks 0–2, 2–14 and 14–27, respectively. Incidence rate for any IMI increased with age and with the presence of an IMI in the contralateral gland, and varied among herds (p<0.001). The transmission of each pathogen was better modelled assuming contagiousness (Reed-Frost models), than not (Greenwood models).

At gland level, IMI increased SCC at all stages of lactation (p<0.001). The gland prevalence of IMI within herds was positively associated with ln BTSCC at Week 2 (p=0.02), but not Weeks 14 or 27 (p>0.05).

CONCLUSIONS: Prevalence of IMI increased with stage of lactation, but the highest incidence rate of new IMI occurred in early lactation. Models accounting for the contagious nature of infection fitted better than those not accounting for contagiousness. BTSCC was only associated with prevalence of IMI in early lactation.

CLINICAL RELEVANCE: Reduction of BTSCC in dairy goats may be best achieved by minimising the prevalence and incidence of new IMI in early lactation. Further studies are required to define management factors associated with the between herd, and stage of lactation, effects on prevalence and incidence rate in order to reduce BTSCC throughout lactation.     

Lectin‐binding Sites on the Normal and Pathologic Uterus of Sows

The lectin‐binding pattern was compared in the normal and pathological uterus of sows during the ovarian cycle. The following biotinylated lectins were used: Con A, DBA, SBA, PNA, RCA‐I, UEA‐I and WGA. Glycoconjugate labelling showed differences between phases of ovarian cycle and presence of morphologic lesions. Cystic endometrial hyperplasia increased the RCA‐I reaction in the apical region of the glandular epithelium. There was higher intensity of labelling of WGA in the glandular epithelium in uteri with endometritis. In addition, increased Con A binding in the glandular epithelium and mild reduction of UEA‐I reactivity in the glycocalyx of the glandular epithelium were detected in the cases of endometritis. The results of this study show that morphologic alterations modify the sugar pattern in the porcine uterus. These modifications in glycoconjugates may be one of the reasons for decreased fertility in sows.     

Infertility associated with the absence of endometrial progesterone receptors in a bitch

A three‐year‐old intact female Old English sheepdog was presented for evaluation of infertility. A uterine biopsy was performed during dioestrus, and the microscopic appearance was inconsistent with progesterone stimulation; the glands were sparse, simple and failed to show coiling, while the glandular epithelium was cuboidal instead of columnar. There was very little evidence of glandular activity. Due to the inappropriate appearance of the glands for the stage of the cycle, immunohistochemistry for progesterone receptors was performed. No progesterone receptor‐positive immunoreactivity was identified in the endometrial luminal epithelium, glandular epithelium or stroma. Weak intranuclear immunoreactivity was identified within the smooth muscle cells of the myometrium. The absence of progesterone receptors within the endometrial glands is the most likely explanation for the abnormal appearance of the endometrium and for this bitch's infertility. To our knowledge, this is the first report of endometrial progesterone receptor absence in a bitch.     

Incidence of catheter-associated urinary tract infection among dogs in a small animal intensive care unit

OBJECTIVE: To determine incidence of and possible risk factors for catheter-associated urinary tract infection (UTI) among dogs hospitalized in an intensive care unit and compare results of bacterial culture of urine samples with results of bacterial culture of catheter tips. DESIGN: Prospective study. ANIMALS: 39 dogs. PROCEDURE: A standard protocol for aseptic catheter placement and maintenance was used. Urine samples were obtained daily and submitted for bacterial culture. When possible, the urinary catheter tip was collected aseptically at the time of catheter removal and submitted for bacterial culture. Bacteria that were obtained were identified and tested for antimicrobial susceptibility. RESULTS: 4 of the 39 (10.3%) dogs developed a UTI. The probability of remaining free from UTI after 1 day in the intensive care unit was 94.9%, and the probability of remaining free from UTI after 4 days was 63.3%. Bacteria isolates were generally common urinary tract pathogens and were susceptible to most antimicrobials. Specific risk factors for catheter-associated UTI, beyond a lack of antimicrobial administration, were not identified. Positive predictive value of bacterial culture of urinary catheter tips was only 25%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that placement of an indwelling urinary catheter in dogs is associated with a low risk of catheter-associated UTI during the first 3 days after catheter placement, provided that adequate precautions are taken for aseptic catheter placement and maintenance. Results of bacterial culture of urinary catheter tips should not be used to predict whether dogs developed catheter-associated UTI.     

Effects of oral administration of a commercial activated charcoal suspension on serum osmolality and lactate concentration in the dog

The purpose of this investigation was to determine the effects of an activated charcoal (AC) suspension containing propylene glycol and glycerol on serum osmolality, osmolal gap, and lactate concentration in dogs. Six healthy adult dogs were administered 4 g/kg AC in a commercially available suspension that contained propylene glycol and glycerol as vehicles. Blood samples were taken before and 1, 4, 6, 8, 12, and 24 hours after the administration of the test suspension. Samples were analyzed for osmolality, blood gases, and concentrations of lactate, sodium, potassium, serum urea nitrogen, and glucose. Osmolal gaps were calculated for each time point. Mean serum osmolality, osmolal gap, and lactate concentration were significantly increased after suspension administration compared to baseline. Serum osmolality increased from 311 mOsm/kg at baseline to 353 mOsm/kg, osmolal gap increased from 5 to 52 mOsm/kg, and lactate concentration increased from 1.9 to 4.5 mmol/L after suspension administration (all P < .01). Three of the 6 dogs vomited between 1 and 3 hours after the administration of the test suspension, and 4 of 6 dogs were lethargic. All dogs drank frequently after AC administration. Commercial AC suspension administered at a clinically relevant dose increases serum osmolality, osmolal gap, and lactate concentration in dogs. These laboratory measures and the clinical signs of vomiting, lethargy, and increased frequency of drinking might complicate the diagnosis or monitoring of some intoxications (such as ethylene glycol) in dogs that have previously received AC suspension containing propylene glycol, glycerol, or both as vehicles.     

Ivermectin toxicity in 17 collies

Ivermectin is widely used in veterinary medicine as an anthelminthic and generally has a wide margin of safety, but Collies are prone to ivermectin toxicity. Two groups of Collies were presented to the University of California Veterinary Medical Teaching Hospital (VMTH) with ivermectin toxicity. The medical records of the 2 groups of Collies were reviewed retrospectively. Group I comprised 5 adult Collies that received at least 400 microg/kg ivermectin p.o. and were presented to the VMTH 3 hours after intoxication. These Collies showed marked clinical signs on presentation. Three of these dogs required mechanical ventilation and were euthanized for financial reasons; the remaining 2 dogs were comatose but recovered in 5-7 days. Group II was comprised of 12 adult Collies presented to the VMTH 2 days (n = 10) and 5 days (n = 2) after subcutaneous injection of 200-250 microg/kg ivermectin. These animals showed greater variation in severity of illness among individuals; 5 animals progressed to stupor or coma, whereas 4 animals remained ambulatory. Most of these dogs' clinical signs deteriorated from the day of intoxication until approximately day 6, from which time they showed gradual but steady improvement. All of the Collies in this group survived, but it took 3 weeks for most of them to recover. Collies suffering from ivermectin toxicity can have a severe and prolonged clinical course requiring intensive nursing care. Respiratory, cardiovascular, and nutritional support may all be required. With appropriate care, however, the prognosis for complete recovery is good.     

Performance, forage utilization, and ergovaline consumption by beef cows grazing endophyte fungus-infected tall fescue, endophyte fungus-free tall fescue, or orchardgrass pastures.

Two 120-d trials (May to September, 1988 and 1989) determined the effects of grazing tall fescue (two varieties) or orchardgrass on forage intake and performance by beef cows. Each summer, 48 cow-calf pairs grazed endophyte-infected Kentucky-31 tall fescue (KY-31), endophyte-free Mozark tall fescue (MOZARK), or Hallmark orchardgrass (OG) pastures (16 pairs/treatment). Forage OM intakes and digestibilities were determined during June and August each year. Cow and calf BW and milk production were determined every 28 d. During June of both years, OM intakes did not differ (P greater than .10) among treatments. During August of 1988, intakes were 18% lower (P less than .05) by KY-31 cows (1.6% of BW) than by MOZARK or OG cows (average 1.95% of BW); however, no differences (P greater than .10) were measured in August of 1989. Estimates of ergovaline consumption during June from KY-31 were between 4.2 (1988) and 6.0 mg/d (1989), whereas August estimates were between 1.1 (1988) and 2.8 mg/d (1989). Ergovaline in MOZARK estrusa was below detection limits, except in August of 1989. Cows that grazed KY-31 lost three times (P less than .01) more BW than cows that grazed MOZARK or OG (42 vs 9 and 13 kg, respectively). Milk production by KY-31 cows was 25% lower (P less than .01) than that by cows that grazed MOZARK or OG (6.0 vs average of 8.0 kg/d). Similarly, slower (P less than .01) calf gains were noted for KY-31 than for MOZARK or OG (.72 vs .89 and .88 kg/d, respectively). Cows grazing KY-31 experienced accelerated BW loss and reduced milk production and weaned lighter calves than did cows grazing MOZARK or OG. Decreased performance was not explained by consistently reduced forage intakes; hence, altered nutrient utilization was suspected.