Estrus synchronization and expression of estrus behaviors during periovulatory period in doublesynch treated buffalypso (Bubalus bubalis) in Trinidad

Objectives: Experiment was conducted to investigate (a) the effect of the doublesynch protocol on pregnancy rate in buffalypso (b) the effectiveness of the doublesynch protocol for estrous synchronization and (c) to observe and record signs of estrous in buffalypso. Design and Methodology: In this study, eleven buffalypsoes (n=11) were administered Prostaglandin (PGF2α)on day 0, Gonadotropin-releasing hormone (GnRH) on day 2, a second PGF2α injection on day 9, and a second GnRH injection on day 11. Timed artificial insemination (TAI) was performed 16 and 24 hours after the second GnRH injection. Eleven buffalypso females (n=11) were bred after spontaneous estrus was detected (control group). Oestrous behaviour and intensity were recorded in all the experimental animals, transrectal palpation and ultrasound was performed 60 days postinsemination to determine conception rate. Results: All buffalypsoes treated with the doublesynch protocol elicited signs of swollen vulva and frequent urination which are classical signs of behavioural estrus. The pregnancy rates were 54.5% using TAI in all the treated buffalypsoes and 45.5% for the control group buffalypsoes. The conception rate between doublesynch treatment and Aripo farm herd were also compared and it was found that doublesynch treated buffalypsoes had higher conception rate (54.5%) compared to the overall Aripo farm herd (24.0%) by artificial insemination. Conclusion: The doublesynch protocol effectively synchronized the estrus in buffalypsoes. The study also demonstrated that this protocol followed by TAI enhanced the pregnancy rate with classical signs of estrus in the buffalypsoes.

Survey of ticks of domestic dogs and cattle in Trinidad and Tobago

Objective: Ticks and the pathogens they transmit can cause high morbidity and mortality in domestic animals. As part of a larger study to determine the tickborne pathogens infesting domestic animals and wildlife, the aim of this study was to survey the tick species infesting the canine and cattle populations in Trinidad and Tobago. Design and Methodology: A total of 1,990 ticks were collected off of 179 dogs from 48 areas in Trinidad (n=163) and Tobago (n=16) only between June 2016 and 2018. Ticks were also collected from cattle throughout Trinidad (n=1098) and Tobago (n=306). Collected ticks were morphologically identified using standard taxonomic keys. Results: Only two tick species, Rhipicephalus sanguineus (1,926; 96.8%) and Amblyomma ovale (64; 3.2%) were found on the dogs sampled in Trinidad and Tobago (T&T). A total of 169 (94.4%) dogs and 10 (17.9%) dogs were infested with R. sanguineus and A. ovale respectively. Three dogs (1.7%) were infested with both tick species. Only hunting dogs or those closely associated with them were infested with A. ovale. R. sanguineus was very common throughout both islands whereas A. ovale was restricted to small foci in three rural settlements in both Trinidad (n=2) and Tobago (n=1). Rhipicephalus (Boophilus) microplus was the only tick species found infesting cattle on both islands. Conclusion: R. sanguineus is the most common tick infesting domestic dogs in T&T while A. ovale was found on fewer dogs. Only R. (B). microplus was detected on cattle. R. sanguineus is a known vector of tick-borne diseases in domestic dogs and humans while R. B. microplus can transmit harmful pathogens to cattle. These preliminary findings will aid in determining if there are any possible links between ticks and tick-borne pathogens associated with domestic and wildlife species and possibly humans and give further insight into the potential movement of ticks and their pathogens between the human, animal and tropical forest interface.

Comparative study on responses of cattle and water buffalo (Bubalus bubalis) to experimental inoculation of Brucella abortus biovar 1 by the intraconjunctival route--a preliminary report

The preliminary study was conducted to assess the virulence of a strain of Brucella abortus (1969D) and to compare the susceptibility of water buffalo and cattle calves to infection by the intraconjunctival route. Seven of each cattle and water buffalo (Bubalus bubalis) calves aged 3-6 months were inoculated intraconjunctivally with counts ranging from 1.5 ž 10(7) to 1.7 ž 10(10) colony forming units of B. abortus. Animals were monitored over an 8-week period for clinical manifestations and serological and hematological evidence of infection. At slaughter, eight lymph nodes from each animal were sampled for bacteriological and histopathological assessments. Lymph nodes from three water buffalo (43%) and five cattle (71%) yielded B. abortus (P=0.048). Parotid/prescapular lymph nodes were most sensitive in detecting B. abortus. Our data suggest that B. abortus strain 1969D may be used as challenge strain, and water buffalo appeared to have a lower susceptibility to B. abortus infection than cattle.

Liquid and Frozen Storage of Agouti (Dasyprocta leporina) Semen Extended with UHT Milk, Unpasteurized Coconut Water, and Pasteurized Coconut Water

This study evaluated the effects of semen extension and storage on forward progressive motility % (FPM%) in agouti semen. Three extenders were used; sterilized whole cow's milk (UHT Milk), unpasteurized (CW) and pasteurized coconut water (PCW), and diluted to 50, 100, 150, and 200 ž 10(6) spermatozoa/ml. Experiment 1: 200 ejaculates were extended for liquid storage at 5(∘)C and evaluated every day for 5 days to determine FPM% and its rate of deterioration. Experiment 2: 150 ejaculates were extended for storage as frozen pellets in liquid nitrogen at -195(∘)C, thawed at 30(∘) to 70(∘)C for 20 to 50 seconds after 5 days and evaluated for FPM% and its rate of deterioration. Samples treated with UHT milk and storage at concentrations of 100 ž 10(6) spermatozoa/ml produced the highest means for FPM% and the slowest rates of deterioration during Experiment 1. During Experiment 2 samples thawed at 30(∘)C for 20 seconds exhibited the highest means for FPM% (12.18 ñ 1.33%), 85% rate of deterioration. However, samples were incompletely thawed. This was attributed to the diameter of the frozen pellets which was 1 cm. It was concluded that the liquid storage method was better for short term storage.

The effect of a chronic stressor, lameness, on detailed sexual behaviour and hormonal profiles in milk and plasma of dairy cattle

The objectives of the present study were to quantify the effects of a biological chronic stressor (lameness) on the duration and frequency of different oestrous behaviours in parallel with milk hormone profiles. Dairy cows 51.8 +/- 1.4 days postpartum (n = 59), including 18 non-lame control cows, were scored for lameness and closely observed for signs of oestrus having had their follicular phases synchronized by administration of gonadotrophin-releasing-hormone (GnRH) followed by prostaglandin F(2alpha) (PG) 7 days later. Lameness shortened the period when herd-mates attempted to mount the lame cows (1.83 +/- 0.69 h vs 5.20 +/- 1.53 h; p = 0.042) but did not affect the overall duration of total behaviours (lame 12.3 +/- 1.3 h vs non-lame 15.2 +/- 1.3 h). Lameness also lowered the intensity of oestrus [1417 +/- 206 points (n = 18) vs 2260 +/- 307 points (n = 15); p = 0.029]. Throughout the synchronized oestrous period, lame cows mounted the rear of herd-mates less frequently (p = 0.020) and tended to chin rest less (p = 0.075). Around the period of maximum oestrous intensity, lameness also diminished the proportion of cows mounting the rear of another cow and chin resting (p = 0.048, p = 0.037, respectively). Furthermore, lame cows had lower progesterone values during the 6 days before oestrous (p < or = 0.05). Fewer lame cows were observed in oestrus following PG (non-lame 83%, lame 53%; p = 0.030); however, if prior progesterone concentrations were elevated, lame cows were just as likely to be observed in oestrus. In conclusion, following endogenous progesterone exposure, lameness shortens the period when herd-mates attempt to mount lame cows but does not affect the incidence of oestrous. However, lame cows are mounted less frequently and express oestrus of lower intensity. This is associated with lower progesterone prior to oestrus but not with abnormal oestradiol or cortisol profiles in daily milk samples.

Calving-to-conception interval of dairy cows in a farm in Trinidad and Tobago.

Factors affecting calving-to-conception interval (CCI) in dairy cows on a farm in Trinidad and Tobago were studied. Retrospective data from the period January 200 to December 2004 were collected from records (n=178) of the University Field Station dairy herd and analysed using a multivariable regression model. Predictor variables included: parity, season of calving [wet vs. dry- dry season (mean rainfall 48.8mm) runs from January to May and the wet season (mean rainfall 194.9mm) from June to December], presence or absence of periparturient disease (PPD), and milk yield. Milk production data were adjusted to an annual yield by correcting the yield between calving intervals to a 365-day production. The natural logarithm transformation of the CCI (LCCI) was fitted as the response of variable in a regression model. The regression coefficients for parity and season of calving were not significant and were 1.4 days longer than females without periparturient disease (P=0.04). Higher milk- producing cows had shorter CCIs. For each kilogramme increase in milk yield, there was a one-day decrease in CCI (P=0.0001). The adjusted R squared was 24% and the predictive regression equation was: LCCI=5.22+0.33 (PPD)-0.0001 (milk yield). The findings in this study support the need for more comprehensive investigations at national and regional levels in order to screen for other predictors in an effort to deliver better dairy herd programs health.

Calving-to-conception interval of dairy cows in a farm in Trinidad and Tobago.

Factors affecting calving-to-conception interval (CCI) in dairy cows on a farm in Trinidad and Tobago were studied. Retrospective data from the period January 200 to December 2004 were collected from records (n=178) of the University Field Station dairy herd and analysed using a multivariable regression model. Predictor variables included: parity, season of calving [wet vs. dry- dry season (mean rainfall 48.8mm) runs from January to May and the wet season (mean rainfall 194.9mm) from June to December], presence or absence of periparturient disease (PPD), and milk yield. Milk production data were adjusted to an annual yield by correcting the yield between calving intervals to a 365-day production. The natural logarithm transformation of the CCI (LCCI) was fitted as the response of variable in a regression model. The regression coefficients for parity and season of calving were not significant and were 1.4 days longer than females without periparturient disease (P=0.04). Higher milk- producing cows had shorter CCIs. For each kilogramme increase in milk yield, there was a one-day decrease in CCI (P=0.0001). The adjusted R squared was 24% and the predictive regression equation was: LCCI=5.22+0.33 (PPD)-0.0001 (milk yield). The findings in this study support the need for more comprehensive investigations at national and regional levels in order to screen for other predictors in an effort to deliver better dairy herd programs health.

Pre-processed bovine milk quality in Trinidad: Prevalence and characteristics of bacterial pathogens and occurrence of antimicrobial residues in milk from collection centres

The study was conducted to assess the impact of the changes in the milk collection system in Trinidad (from twice daily collection to once, introduction of chilling facilities to the collection centres and transportation of milk to the processing plant in insulated truck instead of in metal churns at ambient temperature) on the microbial load and antimicrobial residue quality of the milk as well as the temperature and pH of milk, using standard methods. The presence of antimicrobial residues was detected using the Delvo test kit. Of a total of 266 milk samples from churns, the mean ñ sd temperature and log10 ñ sd TAPC per ml was 20.36 ñ 7.91 øC and 6.3 ñ 1.09 respectively. For 20 milk samples from the chillers, the mean temperature and log10 ñ sd TAPC per ml was 15.10 ñ 2.73 øC and 7.04 ñ 0.33 respectively compared with corresponding values for 36 samples collected from the truck, 11.64 ñ 4.22 øC and 7.11 ñ 0.62 respectively (P < 0.05; X2). The mean TAPC, staphylococcal and E. coli counts per ml of milk from churns were significantly (P < 0.05; X2) higher for milk at low temperature (0–20 øC) compared with milk at high temperature (>30 øC). Eight (4.2 per cent) of 192 milk samples tested contained antimicrobial residues. Of 168 S. aureus isolates tested, 24 (14.3 per cent) were enterotoxigenic while 53 (45.3 per cent) of 117 isolates tested exhibited resistance to various antimicrobial agents while of 386 isolates of E. coli tested, 3 (0.8 per cent) were O157 strain and 129 (64.5 per cent) of 200 isolates exhibited resistance to antimicrobial agents. It was concluded that despite the changes, the microbial load of milk was still high suggesting poor sanitary practices at the farm level. The detection of antimicrobial residues agents coupled with toxigenic S. aureus and E. coli isolates could pose health hazards to consumers.

Likelihood ratio estimation without gold standard: a case study evaluating brucellosis c-ELISA in cattle and water buffalo in Trinidad

The likelihood ratio (LR) is a measure of association that quantifies how many more times likely a particular test result is from an infected animal compared to one that is uninfected. They are ratios of conditional probabilities and cannot be interpreted at the individual animal level without information concerning pretest probabilities. Their usefulness is that they can be used to update the prior belief that the individual has the outcome of interest through a modification of Bayes' theorem. Bayesian analytic techniques can be used for the evaluation of diagnostic tests and estimation of LRs when information concerning a gold standard is not available. As an example, these techniques were applied to the estimation of LRs for a competitive ELISA (c-ELISA) for diagnosis of Brucella abortus infection in cattle and water buffalo in Trinidad.Sera from four herds of cattle (n = 391) and four herds of water buffalo (n = 381) in Trinidad were evaluated for Brucella-specific antibodies using a c-ELISA. On the basis of previous serologic (agglutination) test results in the same animals, iterative simulation modeling was used to classify animals as positive or negative for Brucella infection. LRs were calculated for six categories of the c-ELISA proportion inhibition (PI) results pooled for cattle and water buffalo and yielded the following estimations (95% probability intervals): <0.10 PI, 0.05 (0ùC0.13); 0.10ùC0.249 PI, 0.11 (0.04ùC0.20); 0.25ùC0.349 PI, 0.77 (0.23ùC1.63); 0.35-0.499 PI, 3.22 (1.39ùC6.84); 0.50ùC0.749 PI, 17.9 (6.39ùC77.4); ­í0.75 PI, 423 (129ùC­è). LRs are important for calculation of post-test probabilities and maintaining the quantitative nature of diagnostic test results.

Bovine epigastric heteropagus in Trinidad and Tobago: a case study

Congenital duplications are common causes of dystocia in farm animals, especially in cattle. Heteropagus or conjoined asymmetric twins can be differentiated into a dominant and a parasitic twin, which can be classified further by the development of the parasitic twin and its anatomical attachment to the dominant twin (autosite). In epigastric heteropagus, the parasitic twin is attached to the autosite in the epigastric area. Epigastric heteropagus is a very rare condition in all species, but it has previously been reported in human beings (Chadhaand others 1993). There have been no reports of heteropagus in cattle in Trinidad and Tobago, and there is a paucity of information on bovine epigastric heteropagus in the literature. Reports of congenital abnormalities in Trinidad include craniopagus in a calf (Isitor and Adogwa 1992), perosomus elumbus in a goat (Cazabon and others 1994) and cephalothoracopagus in sheep (Cazabon and Adogwa 2003). The interest in congenital abnormalities lies mainly in the aetiology and its implications, such as genetic defects and environmental toxins. This short communication describes the firstcase of epigastric heteropagus in cattle reported in Trinidad and Tobago.

Ear-tag retention and identification methods for extensively managed water buffalo (Bubalus bubalis) in Trinidad

Thirty-two young domestic water buffalo were studied to evaluate ear-tag retention during an epidemiologic field trial. Plastic ear-tags were placed in both ears before the start of the trial, which was implemented in an extensively managed domestic water buffalo herd of approximately 1000 animals in Trinidad from 1999–2001. The presence or absence of ear-tags was recorded at the times of animal handling. The rate of ear-tag loss was modeled using a parametric survival analysis assuming an exponential rate of loss. A gamma distribution was used to estimate the amount of time that each animal would be positively identified based only on the presence or absence of one or more ear-tags. The overall median ear-tag retention was 272 days. The estimated rate of ear-tag loss was 0.0024 ear-tags lost per day. The use of ear-tags alone might not be sufficient for long-term identification of extensively managed animal populations.

Ear-tag retention and identification methods for extensively managed water buffalo (Bubalus bubalis) in Trinidad

Thirty-two young domestic water buffalo were studied to evaluate ear-tag retention during an epidemiologic field trial. Plastic ear-tags were placed in both ears before the start of the trial, which was implemented in an extensively managed domestic water buffalo herd of approximately 1000 animals in Trinidad from 1999-2001. The presence or absence of ear-tags was recorded at the times of animal handling. The rate of ear-tag loss was modeled using a parametric survival analysis assuming an exponential rate of loss. A gamma distribution was used to estimate the amount of time that each animal would be positively identified based only on the presence or absence of one or more ear-tags. The overall median ear-tag retention was 272 days. The estimated rate of ear-tag loss was 0.0024 ear-tags lost per day. The use of ear-tags alone might not be sufficient for long-term identification of extensively managed animal populations.

Serologic responses, biosafety and clearance of four dosages of Brucella abortus strain RB51 in 6-10 months old water buffalo (Bubalus bubalis)

Thirty water buffalo were obtained from a brucellosis-free farm in order to evaluate antibody responses, bacterial clearance and safety to Brucella abortus strain RB51 vaccine in a dose response study. The animals were randomly divided into five treatment groups. Groups I–V received the recommended dose of RB51 vaccine (RD) once, RD twice 4 weeks apart, double RD once, double RD twice 4 weeks apart and saline once, respectively. Antibody responses to RB51 were monitored at 2, 4, 6, 8, 10, 12, 16 18, 22, 24 and 27 post-initial-inoculation weeks (PIW). Clearance of RB51 from the prescapular lymph node was evaluated at 2, 4, 6, 12, 18 and 24 PIW for groups 1, III and V and at 6, 8, 10, 16, 22 and 27 PIW for groups II and IV. To evaluate shedding of the RB51 strain, nasal, conjunctival, vaginal or preputial swabs were taken from all experimental animals at 1, 2, 3, 4, 6, 8 and 12 PIW. Sera taken at all PIW were negative for field strain B. abortus by both the buffered plate agglutination test (BPAT) and competitive enzyme-linked immunosorbent assay (c-ELISA). Antibody responses to RB51 were demonstrated in all vaccinates but not in the controls, up to 12 PIW, by complement fixation test (CFT) and the dot-blot assay with an 83.7% agreement for both tests. Clearance of RB51 occurred between 6 and 12 PIW in group I but less than 2 weeks after booster vaccinations in groups II and IV and between 4 and 6 PIW in group III. RB51 was not recovered at any time from swabs obtained from either RB51-vaccinates or non-vaccinates. The results of this study indicate that serologic responses to RB51 vaccination can be monitored by both CFT and dot-blot assay in water buffalo. Our data also indicates that RB51 vaccination does not interfere with brucellosis sero-surveillance and is safe (no serological and bacteriological evidence of spread to non-vaccinates, no adverse clinical signs or detectable abnormalities on haematology and serum biochemistry) for use in water buffalo (AU)

Molecular characterization of rabies virus isolates from Trinidad

Bovine rabies continues to be a serious problem facing the cattle industry in South and Central America. Although Trinidad played an important role in originally demonstrating the link between bats and bovine rabies, relatively little is known about rabies in Trinidad, an island 7miles off the coast of Venezuela. In order to obtain a more complete understanding of bovine rabies in the region, we report herein on a study undertaken in Trinidad to characterize isolates of rabies virus obtained from infected cattle. A portion of the nucleotide sequence of the nucleoprotein gene from six rabies virus isolates collected from bovine rabies from the years 1997, 1998 and 2000 was determined and compared both to themselves and the nucleotide sequence of other South American isolates. Results indicate that there are at least two independently evolving variants of rabies virus in Trinidad. The nucleotide sequence of either variant failed to match completely the sequence of South American isolates. However, the lack of South American isolates from coastal regions facing Trinidad leaves undetermined the question of South American influence on rabies in Trinidad. The results of this study helps complete the picture of bovine rabies in the South American region and provide basic information required locally for the creation of an effective rabies control and eradication strategy.

A preliminary investigation on the use of imidocarb dipropionate in the prophylaxis of anaplasmosis and babesiosis [abstract]

The prophylactic effect of imidocarb dipropionate on anaplasmosis and babesiosis was studied using twenty-seven heifers at the university field station. Fifteen animals were administered imidocarb dipropionate intramuscularly at a dose of 2mg-kg 1 while twelve were left as controls. All animals were subsequently turned out to pasture from a feedlot environment which was tick-free. Over a period of seven months, the heifers were monitored for tick infestation, weight gain, body temperature, haematological para-meters such as packed cell volume, haemoglobin, white blood cell count, total plasma protein, the differences in other parameters between treated and untreated control heifers were not significantly different. It is concluded that the administration of imidocarb dipropionate for the purpose of prophylaxis of babesiosis and/or anaplasmosis in this situation was of no significant value. (AU)

Understanding the mechanism of action of Cytochrome c Oxidase in normal and disease states: shark heart enzyme, a potential model

Cytochrome c oxidase, the final member of the electron transport chain, is crucial to respiration and also contributes to the synthesis of cellular ATP. The total absence of this enzyme is incompatible with life and its deficiency or malfunction leads to a number of serious disease states. Understanding the mechanism of action of this enzyme, which is an important prerequisite to unravelling its role in the pathogenesis of disease states, is hampered by the lack of suitable enzyme models. The bovine enzyme, which are structually simple, appear to follow a different mechanism of action. The hammer head shark is a seasonal resident of the warm waters of the Caribbean Sea. The work presented here indicates that, like the bovine enzyme, the enzyme of the heart of this shark (i) possesses thirteen subunits and two substrate binding sites and (ii) exhibits biphasic kinetics. The work also confirms that, unlike the bovine enzyme which is dimeric, the shark enzyme functions as a monomer. Given this latter simplifying feature, in conjunction with its kinetic and structural similarities to the more complex mammalian varieties, we propose that shark heart cytochrome c oxidase replace the bovine and bacterial forms as the enzyme of choice for model studies.(Au)

The presence of Coxiella-like organisms in the commercial foetal bovine sera.

During routine passaging of chicken embryo fibroblasts minute extracellular organisms were observed to develop in the cultures. These organisms could be detected in three different batches of commercial sera from three different suppliers. Passage of the organisms into laboratory guinea pigs resulted into their detection in the mononuclear leukocytes. The biological characteristics of these organisms are similar to those of Coxiella, already described by previous workers. The present results indicate that commercial sera could serve as vehicles of these organisms.

The presence of Coxiella-like organisms in the commercial foetal bovine sera.

During routine passaging of chicken embryo fibroblasts minute extracellular organisms were observed to develop in the cultures. These organisms could be detected in three different batches of commercial sera from three different suppliers. Passage of the organisms into laboratory guinea pigs resulted into their detection in the mononuclear leukocytes. The biological characteristics of these organisms are similar to those of Coxiella, already described by previous workers. The present results indicate that commercial sera could serve as vehicles of these organisms.

A longitudinal study on enteropathogenic infections of livestock in Trinidad

A longitudinal study was conducted on selected livestock farms to determine the prevalence of enteropathogens in diarrhoeic and non-diarrhoeic animals. The enteropathogens assayed from faecal samples and rectal swabs were bacteria (Escherichia coli, Campylobacter spp. Salmonella spp. and Yersinia enterocolitica), parasites (coccidia, gastrointestinal nematodes and Cryptosporidium spp.) and viruses (group A rotavirus and parvovirus). The prevalence of the enteropathogens in various animal species was related to age and month of the year. Generally, younger animals presented a higher prevalence of infection by enteropathogens than older animals while most infections occurred between the months of January and April.