Productivity of Thai Brahman and Simmental-Brahman crossbred (Kabinburi) cattle in central Thailand

The productivity of the new crossbred cattle Kabinburi (K) was compared to that of Thai Brahman (TB) using 756 production records from K cattle and 1,316 production records from TB cattle kept at three locations in Thailand. The data were analyzed for the effect of breeds and locations. The ambient temperature, the humidity, the Temperature–Humidity Index (THI) and the rainfall of the three locations were different. Lamphayaklang Livestock Research and Breeding Center (LP) had the highest rainfall/year followed by Nongkwang Livestock Research and Breeding Center (NK), and Prachinburi Livestock Breeding Station (PC). Kabinburi cattle had a higher bodyweight at birth as well as at 200, 400 and 600 days of age than TB cattle. Furthermore, K heifers gave birth to their first calf at a younger age and had a shorter calving interval than TB cows. Thai Brahman cattle kept at LP had significantly higher bodyweight at 400 and 600 days than the animals kept at NK, but bodyweight at birth and 600 days of age were not significantly different. Thai Brahman cattle kept at LP were younger at first calving and had a shorter calving interval than the animals kept at NK. K cattle kept at NK were heavier at birth and at 200, 400 and 600 days of age than the animals kept at PC. Furthermore, Kabinburi cows kept at NK were younger at first calving (P < 0.01), but the calving interval was not different between the two groups kept at NK or PC.     

Detection of heat-stable and heat-labile enterotoxin genes of Escherichia coli in diarrhoeic faecal samples of mithun (Bos frontalis) calves by polymerase chain reaction

Aims:  To find out the prevalence of different serogroups of Escherichia coli ( E. coli ) and to detect heat-stable (ST) and heat-labile (LT) enterotoxin genes of enterotoxigenic E. coli (ETEC) from the faeces of mithun calves with diarrhoea.
Methods and Results:  Faecal samples obtained from 65 diarrhoeic mithun calves of under 2 months of age were examined for E. coli using polymerase chain reaction (PCR). Fifty-four E. coli isolates were obtained from those samples, which belonged to 38 different serogroups. Out of 54 isolates tested by PCR, two isolates (3·70%) belonging to serogroups O26 and O55 were found to possess gene that code for ST enterotoxin and one isolate (1·85%) belonging to serogroup O125 was found to carry LT enterotoxin gene.
Conclusions:  Escherichia coli isolates from diarrhoeic mithun calves were found to possess ST and LT enterotoxin genes, which are designated as ETEC, and these isolates can be detected through PCR using specific primers.
Significance and Impact of the Study:  This study reports the isolation of ETEC possessing ST and LT enterotoxin genes for the first time and ETEC could be a cause of diarrhoea in mithun calves leading to calf mortality.     

Isolation of bovine intestinal Lactobacillus plantarum and Pediococcus acidilactici with inhibitory activity against Escherichia coli O157 and F5

Aims:  The growth rate of bovine lactic acid bacteria (LAB) in five different culture conditions, and their inhibitory activity against Escherichia coli O157 and F5 in two assays was assessed to identify LAB for potential prophylactic use in cattle.
Methods and Results:  106 bovine-derived faecal/intestinal LAB were tested in vitro for tolerance to pH 2·0, pH 4·0, 0·15% and 0·3% bile, aerobic incubation, and for inhibitory activity against E. coli O157 ( n  = 3) and F5 ( n  = 1). While no LAB grew at pH 2·0, LAB survivability varied between 35% and 100% on the other tests. Exactly 7·6% (8/106) of LAB supernatants inhibited the growth of E. coli in two assays, whereas 6·6% (7/106) of isolates enhanced the growth of all E. coli strains. Partial 16s rRNA gene sequencing of six best isolates (95th percentile) revealed that five were Lactobacillus plantarum and one Pediococcus acidilactici.
Conclusion:  Lactobacillus plantarum with acid/bile and aerobic resistance and inhibitory activity against E. coli O157 and F5 inhabit the intestinal tract of healthy cattle. Some LAB may enhance E. coli growth.
Significance and Impact of the Study:  Lactobacillus plantarum and P. acidilactici are natural plant micro-organisms and studied silage inoculants. Their identification from gastrointestinal samples of healthy cattle is prophylactically promising.     

Development of captive bongos (Tragelaphus eurycerus): Activity budgets and developmental milestones

The development of changes in visual orientation, posture, activity budgets, and behavioral milestones was examined in five bongo calves which were observed from birth to 4 or 6 months of age. The only significant change in the calves' visual orientation was an increase in orientation to food. Reclining declined significantly over weeks, while standing increased and moving did not change. Overall, stationary behaviors dominated the activity budget, but decreased significantly over the study. The category that included locomotion, object exploration, and auto-play did not change, while forage and rumination increased significantly. Contrary to expectation, the decline in suckling was not significant. Affiliative interactions with the dam decreased significantly during the study, but increases in affiliation with other bongos were not significant. Levels of agonistic behavior between the calves and their dams and other herd members were low throughout the study, and did not change significantly. One female calf achieved several developmental milestones later than the others. It is suggested that these differences may have been influenced by the dominance status of her dam. The results conform to the general developmental pattern of “hider” bovids. Bongos, however, show somewhat different patterns of social development than eland, which are reported to be more precocial in expression of aggressive and sexual behaviors. © 1992 Wiley-Liss, Inc.     

Occurrence of enterotoxigenic and nonenterotoxigenic Bacteroides fragilis in calves and evaluation of their antimicrobial susceptibility

Bacteroides fragilis is considered an important clinical pathogen and the most common anaerobe isolated from human and animal clinical specimens; enterotoxigenic strains produce diarrhea. The presence of enterotoxigenic (ETBF) and nonenterotoxigenic B. fragilis in stool samples from calves with or without acute diarrhea and the antimicrobial susceptibility of the strains were evaluated. The stool samples were plated onto a selective B. fragilis-bile-esculin agar, and incubated anaerobically (10% CO(2)/90% N(2)), at 37 degrees C, for 72 h. Species of the B. fragilis group were identified by using the API 32-A kit. Enterotoxigenic strains were detected by PCR and the cytotoxic assay. From 54 diarrhea and 54 nondiarrhea stools, 124 and 92 members of the B. fragilis group, respectively, were recovered. Only two ETBF strains were isolated from two different diarrhea samples and the bft gene was detected in both. Moreover, the bft gene was detected in DNA from four different diarrheal stools samples but no ETBF strain was recovered. All the bacteria were susceptible to chloramphenicol, imipenem, moxifloxacin, piperacillin/tazobactam, metronidazole and tigecycline. Most of the isolates from both calves with and without diarrhea were resistant to all metals. Our results are of concern, and suggest the need to increase the surveillance of antibiotic and metal resistance of this microbial group isolated from animal production such as calves.     

Effects of isovalerate supplements on morphology and functional gene expression of rumen mucosa in pre- and post-weaning dairy calves

Isovalerate supplements could stimulate rumen development by improving morphology and function of rumen mucosa, and then promote the growth of calves. This study was done to evaluate the effects of isovalerate supplements on morphology and functional gene expression of rumen mucosa in dairy calves. In total, 48 Chinese Holstein male calves with 15 days of age and 45.1±0.36 kg of BW were randomly assigned to four groups. The treatments were: control, low-isovalerate, moderate-isovalerate and high-isovalerate with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. Supplementary isovalerate was hand-mixed into milk in pre-weaning calves and into concentrate portion in post-weaning calves. The study consisted of a 15-day-adaptation period and a 60-day-sampling period. Calves were weaned at 60 days of age. Three calves were slaughtered from each of the four treatments at 30, 60 and 90 days of age. The weight of body and stomach were measured, samples of ruminal tissues and blood were analyzed. Total stomach weight, total stomach to BW ratio, rumen wall and keratinized layer thickness, serum growth hormone and IGF-1 for both pre- and post-weaning calves increased linearly with increasing isovalerate supplements. Rumen to total stomach weight ratio, the length and width of rumen papillae, and serum β-hydroxybutyrate increased linearly for post-weaning calves. However, abomasum weight to total stomach weight ratio decreased linearly for both pre- and post-weaning calves. The relative messenger RNA expression for growth hormone receptor, IGF-1 receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly for post-weaning calves. Our results suggested that isovalerate supplements promoted rumen development in a dose-dependent manner. The optimum dose was 6.0 g isovalerate per calf per day.     

Validation of indicators used to assess unconsciousness in veal calves at slaughter

European legislation states that after stunning regular checks should be performed to guarantee animals are unconscious between the end of the stunning process and death. When animals are killed without prior stunning these checks should be performed before the animal is released from restraint. The validity of certain indicators used to assess unconsciousness under different stunning and slaughter conditions is under debate. The aim of this study was to validate the absence of threat-, withdrawal-, corneal- and eyelid reflex as indicators to assess unconsciousness in calves subjected to different stunning and slaughter methods. Calves (201±22 kg) were randomly assigned to one of the following four treatments: (1) Captive bolt stunning followed by neck cut in an inverted position (n=25); (2) Non-stunned slaughter in an upright position (n=7); (3) Non-stunned slaughter in an inverted position (180° rotation) (n=25); (4) Non-stunned slaughter in an upright position followed by captive bolt stunning 40 s after the neck cut (n=25). Each calf was equipped with non-invasive electroencephalogram (EEG) electrodes before the slaughter procedure. All reflexes were verified once before the slaughter procedure. At the beginning of the procedure (T=0 s) calves were stunned (treatment 1) or neck cut in an upright position (treatment 2, 4) or inverted position (treatment 3). Calves of treatment 4 were captive bolt stunned 34±8 s after the neck cut. Reflexes were assessed every 20 s from T=15 s for all treatments until all reflex tests resulted in a negative response three times in a row and a flat line EEG was observed. In addition, reflexes were assessed 5 s after captive bolt stunning in calves of treatments 1 and 4. Visual assessment of changes in the amplitude and frequency of EEG traces was used to determine loss of consciousness. Timing of loss of consciousness was related to timing of loss of reflexes. After captive bolt stunning, absence of threat-, withdrawal-, corneal- and eyelid reflex indicated unconsciousness as determined by EEG recordings. After non-stunned slaughter, both threat- and withdrawal reflex were on average lost before calves were unconscious based on EEG recordings. The eyelid- and corneal reflex were on average lost after calves had lost consciousness based on EEG recordings and appeared to be distinctly conservative indicators of unconsciousness in non-stunned slaughtered calves since they were observed until 76±50 and 85±45 s (mean±SD), respectively, after EEG-based loss of consciousness.     

Ostertagia ostertagi: establishment of patent infections in calves by intravenous inoculation

In two experiments calves raised free of parasite infection were given parenteral injections of Ostertagia ostertagi infective larvae to determine if patent infections might result. Patency was achieved by intravenous injection of larvae. Ten calves of different age (3–8 months) and sex were given intravenous, subcutaneous, and intraperitoneal injections of infective larvae. These calves were not necropsied; patency was based on fecal egg counts. Six calves injected intravenously all achieved patency (17–21 days after inoculation). Two calves each were inoculated subcutaneously and intraperitoneally; patency was observed in none. Calves given primary intravenous inoculation responded with higher levels of ova production to subsequent oral challenge inoculation.In a second experiment, six 2–3-month-old calves were injected intravenously with 186,000 infective larvae. Calves were killed at 2, 7, 12, 20 and 30 days after inoculation and had a tissue reaction in the lungs to migrating larvae characterized by focal granulomas, interstitial thickening of alveolar walls, and some hemorrhage. Infective larvae were recovered from the lungs at 2, 7 and 12 days, fourth stage larvae from the abomasum at 7 and 12 days, and adults only from the abomasum at 20 and 30 days. It was considered that larvae reached the abomasum by way of the trachea and by then being swallowed. Clinical signs of disease were not observed.     

圈养丹顶鹤与白枕鹤杂交繁育

我园一只雄性丹顶鹤与一只雌性白枕鹤于2001年开始自然配对产蛋,3年共产51枚,经人工孵化育雏,目前存活15只。杂种鹤在第4周后进入快速增长阶段,在12周达到最高峰,16周后增长速度明显下降,18周后部分指标停止增长。外观上,出生至3月龄时,幼鹤整体颜色都呈黄褐色,以后变化基本一致。目前,2001及2002年存活杂种鹤颜色以白色为主,夹杂着灰色羽毛。     

First investigations to refine video-based IR thermography as a non-invasive tool to monitor the body temperature of calves

In this study, a video-based infrared camera (IRC) was investigated as a tool to monitor the body temperature of calves. Body surface temperatures were measured contactless using videos from an IRC fixed at a certain location in the calf feeder. The body surface temperatures were analysed retrospectively at three larger areas: the head area (in front of the forehead), the body area (behind forehead) and the area of the entire animal. The rectal temperature served as a reference temperature and was measured with a digital thermometer at the corresponding time point. A total of nine calves (Holstein-Friesians, 8 to 35 weeks old) were examined. The average maximum temperatures of the area of the entire animal (mean±SD: 37.66±0.90°C) and the head area (37.64±0.86°C) were always higher than that of the body area (36.75±1.06°C). The temperatures of the head area and of the entire animal were very similar. However, the maximum temperatures as measured using IRC increased with an increase in calf rectal temperature. The maximum temperatures of each video picture for the entire visible body area of the calves appeared to be sufficient to measure the superficial body temperature. The advantage of the video-based IRC over conventional IR single-picture cameras is that more than one picture per animal can be analysed in a short period of time. This technique provides more data for analysis. Thus, this system shows potential as an indicator for continuous temperature measurements in calves.