Impact of Water Stress on Maize Grown Off-Season in a Subtropical Environment

During the last decade, the production of off‐season maize has increased in several regions of Brazil. Growing maize during this season, with sowing from January through April, imposes several climatic risks that can impact crop yield. This is mainly caused by the high variability of precipitation and the probability of frost during the reproduction phases. High production risks are also partially due to the use of cultivars that are not adapted to the local environmental conditions. The goal of this study was to evaluate crop growth and development and associated yield, yield components and water use efficiency (WUE) for maize hybrids with different maturity ratings grown off‐season in a subtropical environment under both rainfed and irrigated conditions. Three experiments were conducted in 2001 and 2002 in Piracicaba, state of São Paulo, Brazil with four hybrids of different maturity duration, AG9010 (very short season), DAS CO32 and Exceler (short season) and DKB 333B (normal season). Leaf area index (LAI), plant height and dry matter were measured approximately every 18 days. Under rainfed conditions, the soil water content in the deeper layers was reduced, suggesting that the extension of the roots into these layers was a response to soil water limitations. On average, WUE varied from 1.45 kg m⁻³ under rainfed conditions to 1.69 kg m⁻³ under irrigated conditions during 2001. The average yield varied from 4209 kg ha⁻¹ for the hybrids grown under rainfed conditions to 5594 kg ha⁻¹ under irrigated conditions during 2001. Yield reductions under rainfed conditions were affected by the genotype. For the hybrid DKB 333B with a normal maturity, yield was reduced by 25.6 % while the short maturity hybrid Exceler was the least impacted by soil water limitations with a yield reduction of only 8.4 %. To decrease the risk of yield loss, the application of supplemental irrigation should be considered by local farmers, provided that this practice is not restricted by either economic considerations or the availability of sufficient water resources.     

Aberrant development of mammary glands, but precocious expression of beta-casein in transgenic females ubiquitously expressing whey acidic protein transgene

It has been suggested that whey acidic protein (WAP) may function as a protease inhibitor. However, the actual function of WAP remains obscure. We investigated the histological development of the mammary glands of transgenic mice ubiquitously expressing WAP and CAG/WAP transgene. Ubiquitous expression of WAP induced aberrant development of the lobular alveoli of the mammary glands: mammary alveoli that were either aberrantly large or small in size increased in number in the developing mammary glands of these transgenic females during pregnancy and lactation. The expression of beta-casein was precociously induced in the mammary glands of the transgenic females during early pregnancy and accompanying this was a histological observation that abnormally developed lobular alveoli filled with milk proteins appeared in the mammary glands of transgenic females during early pregnancy. However, during lactation, the development of mammary glands was impaired in transgenic females. To investigate the possible paracrine action of WAP associated with mammary gland aberration, we transplanted the mammary tissue of CAG/EGFP transgenic females into the fat pad of virgin CAG/WAP transgenic females and initiated pregnancy by mating. The development of mammary tissue transplanted to the recipient was histologically examined on day 3 of lactation. The results revealed that the development of grafted mammary tissues was impaired in a manner similar to that of the mammary glands of CAG/WAP transgenic females, indicating that the inhibitory effect of WAP acts via a paracrine mechanism. In vitro experiments using HC11 cells with forced expression of exogenous WAP demonstrated the inhibitory function of WAP on proliferation of mammary epithelial cells.     

Three cases of prolapse of the nictitans gland in cats

We report three cases of adult cats showing a prolapse of the gland of the third eyelid. Three different breeds were affected: Burmese, Persian and Domestic Short-haired. In all cases, the disorder occurred spontaneously, without any other ocular sign. Surgical replacement of the gland was performed using the Morgan pocket technique. Good esthetic results were obtained, and no recurrence occurred.     

Effects of altering the sequence of midazolam and propofol during co‐induction of anaesthesia

ObjectiveTo assess the effects of varying the sequence of midazolam and propofol administration on the quality of induction, cardiorespiratory parameters and propofol requirements in dogs.Study designRandomized, controlled, clinical study.AnimalsThirty‐three client owned dogs (ASA I‐III, 0.5–10 years, 5–30 kg).MethodsDogs were premedicated with acepromazine (0.02 mg kg^?1) and morphine (0.4 mg kg^?1) intramuscularly. After 30 minutes, group midazolam‐propofol (MP) received midazolam (0.25 mg kg^?1) intravenously (IV) before propofol (1 mg kg^?1) IV, group propofol‐midazolam (PM) received propofol before midazolam IV at the same doses, and control group (CP) received saline IV, instead of midazolam, before propofol. Supplementary boluses of propofol (0.5 mg kg^?1) were administered to effect to all groups until orotracheal intubation was completed. Behaviour after midazolam administration, quality of sedation and induction, and ease of intubation were scored. Heart rate (HR), respiratory rate, and systolic arterial blood pressure were recorded before premedication, post‐premedication, after midazolam or saline administration, and at 0, 2, 5, and 10 minutes post‐intubation. End‐tidal CO₂ and arterial oxygen haemoglobin saturation were recorded at 2, 5 and 10 minutes post‐intubation.ResultsQuality of sedation and induction, and ease of intubation were similar in all groups. Incidence of excitement was higher in the MP compared to CP (p = 0.014) and PM (p = 0.026) groups. Propofol requirements were decreased in MP and PM groups with respect to CP (p < 0.001), and in PM compared to MP (p = 0.022). The HR decreased after premedication in all groups, and increased after midazolam and subsequent times in MP (p = 0.019) and PM (p = 0.001) groups. Incidence of apnoea and paddling was higher in CP (p = 0.005) and MP (p = 0.031) groups than in PM.Conclusions and clinical relevanceAdministration of midazolam before propofol reduced propofol requirements although caused mild excitement in some dogs. Administration of propofol before midazolam resulted in less excitatory phenomena and greater reduction of propofol requirements.     

Sex differences in the response of yearling horses to handling by unfamiliar humans

In adult horses, pronounced sex differences in behavior exist, and many riders prefer male horses to mares. In the present study, we tested the hypothesis that sex differences in the response of horses to handling emerge before puberty, that is, in sexually immature animals. Warm-blooded yearling horses (6 males and 9 females) were exposed to a stationary human test (exposure to an unfamiliar person for 5 minutes) and a tolerance test (haltering and direct contact with the horse) on 5 consecutive days. The horses' behavior and heart rate were recorded. Male yearling horses displayed significantly less exploratory behavior than females during the stationary human test on days 1 and 2 (P < 0.05). Latency to halter and ease with which horses could be haltered were significantly affected by day (P < 0.05), and a significant interaction of day and sex was detected (P < 0.05; e.g., time for haltering: females, day 1: 23.8 ± 7.8 seconds [±standard error of the mean] and day 5: 21.1 ± 1.7 seconds; males, day 1: 53.6 ± 10.4 seconds and day 5: 19.4 ± 2.2 seconds). Heart rate of the horses in response to the test situations was significantly affected by day (P < 0.01) but not by sex. In conclusion, sex differences in behavior do not only exist in adult horses but are already present in young horses before puberty. When exposed to unfamiliar humans for the first time, male yearling horses display more caution than females.