Effect of chronic administration of a gonadotropin‐releasing agonist on luteal function and pregnancy rates in dairy cattle

Increased embryonic losses may be associated with inadequate progesterone (P4) concentrations in high‐producing lactating dairy cattle. The objectives of the present studies were to determine if chronic administration of a gonadotropin‐releasing hormone (GnRH) agonist, Deslorelin, would increase circulating P4 concentrations and subsequently increase pregnancy rates in dairy cattle. Administration of Deslorelin for 12 days increased (p < .05) luteal volume and circulating P4 concentrations in primiparous lactating dairy cows, but increased only luteal volumes in multiparous cows. Treatment with Deslorelin increased Day 45 pregnancy rates in cows as compared to untreated controls. Chronic treatment with Deslorelin in dairy cattle; (a) increased luteal volume of the primary CL, (b) induced accessory CL, (c) increased circulating P4 concentration in primiparous cows only, (d) did not lengthen the estrous cycle upon removal of treatment, and (e) increased pregnancy rates. Although luteal volume was increased in multiparous cows and circulating P4 concentrations were not with Deslorelin treatment, there was an apparent effect on pregnancy rates. This hormonal strategy may represent a suitable model to address local effects of P4 and GnRH/luteinizing hormone on uterine environment and subsequent embryonic survival.     

Radiotherapy isocenters verified by matching to bony landmarks of the canine and feline head differ when localized using volumetric versus planar imaging

The “gold standard” for verification of patient positioning before linear accelerator‐based stereotactic radiation therapy is kilovoltage cone‐beam computed tomography (kV‐CBCT), which is not uniformly available or utilized; planar imaging is sometimes used instead. The primary aim of this study was to determine if the position of the bony skull, when used as a surrogate for isocenter verification, is different when orthogonal megavoltage (MV) portal or kilovoltage (kV/kV) radiographs are used for image guidance, rather than kV‐CBCT. A secondary aim was to determine the influence of intra‐observer variability, body size and skull conformation on positioning, as determined using these three imaging modalities. Dogs and cats receiving radiotherapy of the head were recruited for this prospective analytical study. Planar (MV portal and kV/kV images) and volumetric (kV‐CBCT) images were acquired before treatment, and manually coregistered with reference images. Differences in skull position when matched based on MV portal, kV/kV images and kV‐CBCT were compared. A total of 65 subjects and 148 unique datasets were evaluated. The Wilcoxon rank‐sum test was used to evaluate effects of transitioning between imaging modalities. When comparing magnitude of shifts in MV to kV‐CBCT, MV to kV/kV and kV/kV to kV‐CBCT, there were statistically significant differences. Results were not measurably impacted by body size, skull conformation or interobserver differences. Based on shift magnitude and direction, an isotropic setup margin of at least 1 mm should be incorporated within the planning target volume when MV or kV planar imaging is used for position verification.     

A comparison of the uterine proteome of mares in oestrus and dioestrus

Proteomic analysis of mare uterine flush fluid provides a minimally invasive technique for studying protein changes associated with the oestrous cycle. The aim of this study was to identify differentially abundant proteins in the uterine flush fluid of mares in oestrus and dioestrus. In this study, uterine flush fluid samples were collected from eight reproductively healthy mares in either oestrus (n = 5) or dioestrus (n = 3). Proteomic analysis was performed using liquid chromatography‐tandem mass spectrometry. Of 172 proteins identified, six proteins (immunoglobulin lambda‐like polypeptide 1, haemoglobin subunit alpha, alpha‐1B‐glycoprotein, serotransferrin, apolipoprotein A‐1, and haemoglobin subunit beta) were significantly more abundant in oestrus. These proteins may contribute to the endometrial defence system through roles in inflammation, immunity or antimicrobial activity. In other species, some of these proteins have been described as immunoglobulins, negative acute phase proteins or defence agents against micro‐organisms. During dioestrus, immunoglobulin alpha‐1 chain C region‐related, complement factor I, CD 109 antigen and uterocalin, were significantly more abundant. Research in other species suggests that these four proteins contribute to the immune response through proposed immunoregulatory characteristics, complement system involvement or roles in B cell–T cell interactions. In conclusion, ten differentially abundant proteins were identified in the uterine flush fluid of mares in oestrus and dioestrus. Targeted studies on these proteins could elucidate their role in uterine defence mechanisms during the oestrous cycle in the mare.     

Calorimetric measurements on chickens given diets with a range of energy concentrations

Eight diets with metabolisable energy (ME) concentrations ranging from 9–1 to 15–3 MJ/kg were given to groups of five chickens kept in respiration calorimeters for 3 to 4 d. Availability of ME ranged from 57% to 79%. One diet differed from the others, but for those groups of chickens on the other seven diets availability of ME was 80% when energy balance was negative and only 60% when positive.

Protein synthesis appeared to continue when chickens were in negative energy balance and fat was frequently catabolised when birds were in positive energy balance, apparently to support protein synthesis.     

Evaluation of intramuscular butorphanol, azaperone, and medetomidine and nasal oxygen insufflation for the chemical immobilization of white-tailed deer, Odocoileus virginianus

Chemical immobilization of wildlife often includes opioids or cyclohexamines. These substances are problematic as a result of their required storage, handling, and record-keeping protocols. A potentially useful alternative sedation protocol includes a combination of butorphanol, azaperone, and medetomidine (BAM: 0.43 mg/kg butorphanol, 0.36 mg/kg azaperone, 0.14 mg/kg medetomidine). One risk of wildlife immobilization with any drug combination is hypoxemia. This may be of particular importance when using an alpha 2 agonist such as medetomidine because of its powerful vasoconstrictive effect. In this prospective study, the BAM combination was evaluated for chemical immobilization of white-tailed deer. Additionally, selected physiologic parameters associated with BAM immobilization, including oxygen saturation via pulse oximetry and arterial blood gas measurement, with and without nasal insufflation of oxygen at a relatively low flow of 3 L/min, were evaluated. The BAM combination resulted in a predictable onset of sedation, with a mean induction time to lateral recumbency of 9.8 +/- 3.6 min. All deer recovered smoothly within a range of 5-20 min after reversal with intramuscular administration of naltrexone, atipamazole, and tolazoline (NAT). Clinically relevant decreases in arterial partial pressure of oxygen (PaO2) and oxygen saturation (SpO2) were observed in animals not receiving supplemental oxygen, while both parameters significantly improved for oxygen-supplemented deer. Pulse oximetry with this protocol was an unreliable indicator of oxygen saturation. In this study, altitude, recumbency, hypoventilation, butorphanol- and medetomidine-specific effects, as well as the potential for alpha 2 agonist-induced pulmonary changes all may have contributed to the development of hypoxemia. Overall, capture of white-tailed deer with the BAM/NAT protocol resulted in excellent chemical immobilization and reversal. Because the BAM combination caused significant hypoxemia that is unreliably detected by pulse oximetry but that may be resolved with nasal oxygen insufflation, routine use of oxygen supplementation is recommended.     

Effects of reconcile (fluoxetine) chewable tablets plus behavior management for canine separation anxiety

Canine separation anxiety is a common behavioral problem presented to veterinarians. Associated behaviors are distressing to both dog and owner, have the potential to disrupt the human-companion animal bond, and may lead to euthanasia. The results of this study demonstrate the clinical efficacy and safety of Reconcile (fluoxetine, 1 to 2 mg/kg/day [0.45 to 0.91 mg/lb/day]), in conjunction with behavior management, for the treatment of canine separation anxiety. The beef flavored chewable formulation was palatable to treated dogs and easy to administer. This study provides to veterinarians and owners valuable information about an effective separation anxiety treatment plan that combines use of Reconcile with behavior modification.     

PALLIATIVE RADIOTHERAPY OF APPENDICULAR OSTEOSARCOMA IN 95 DOGS

Ninety-five dogs with either a presumptive (n = 24) or biopsy confirmed diagnosis (n = 71) of osteosarcoma received palliative radiotherapy using 60Co photons. Parallel opposed beams were used with each dog receiving either 10 Gy on days 0, 7 and 21 (n = 58) or 8 Gy on days 0 and 7 (n = 37). The 8 Gy fractionation scheme was given with the intent of retreating upon relapse from pain relief. Only 9 of 37 (24%) dogs in the 8 Gy group returned for retreatment. Forty-seven of the 95 dogs (49%) received concurrent or sequential chemotherapy. Seventy of the 95 dogs (74%) experienced pain relief following treatment. In dogs experiencing pain relief the median duration of response was 73 days. Numerous clinical variables were evaluated as predictors of response. The only variable significantly related to achieving a response was the use of chemotherapy. The following variables were significantly related to the duration of response: extent of bone lysis, chemotherapy use, length of bone involved and tumor site (humerus). In a multivariate analysis (n = 73 dogs), after adjusting for chemotherapy use, extent of bone involvement (p = 0.01) and tumor site (p = 0.02) retained statistical significance, while degree of bone lysis did not (p = 0.11). No difference in response incidence or duration was found between 3 fractions of 10 Gy vs. 2 fractions of 8 Gy. Administration of a low initial dose with the intent of retreatment was not a successful strategy.     

Exploring tropical fisheries through fishers’ perceptions: Fishing down the food web in the Tonlé Sap,Cambodia

Tropical fisheries are among the most productive fisheries in the world, often providing the primary source of protein for the local population. Despite their importance, data on these systems are relatively limited, thus hampering management and policy development. Here, the implications of increasing fishing pressure are explored by critically evaluating the perceptions of the fishers who rely on these ecosystems to survive. A total of 169 fishers in 26 different fish‐dependent communities in the Tonlé Sap Lake, Cambodia, were surveyed to understand their perceptions of the impact that fishing has had on the ecosystem. The Tonlé Sap is one of the largest, yet poorest studied, freshwater fisheries in the world. Consistent with “fishing down the food web” theory of fisheries, survey data revealed that although fishers observed the total size of fish catch remaining consistent over recent years there has been a drastic decline in the size of individual fish, as well as a reduction in the diversity of species caught. These perceptions are examined with reference to food web theories that explore how fishing pressure leads to ecosystem change, including the more recent “indiscriminate fisheries” theory.