Delineation of temperature-humidity index (THI) as indicator of heat stress in riverine buffaloes (Bubalus bubalis) of a sub-tropical Indian region

The erstwhile developed temperature-humidity index (THI) has been popularly used to indicate heat stress in dairy cattle and often in buffaloes. However, scientific literature suggests differences in thermotolerance and physiological responses to heat stress between cattle and buffalo. Therefore, THI range used to indicate degree of heat stress (mild, moderate, and severe) in cattle should be recalibrated for indicating heat stress in buffaloes. The present study was carried out to delineate THI range to indicate onset and severity of heat stress in buffaloes based on physiological, biochemical, and expression profiling of heat shock response (HSR) genes in animals at different THI. The result indicated early onset of heat stress in buffaloes as compared to cattle. Physiological and biochemical parameters indicated onset of mild signs of heat stress in buffaloes at THI 68-69. Significant deviation in these parameters was again observed at THI range 73-76. At THI 77-80, the physiological and biochemical responses of animals were further intensified indicating extreme alteration in homeostasis. The in vivo expression profiling of HSR genes indicated that members of Hsp70 gene family are expressed in a temporal pattern over different THIs, whereas expressions of Hsf genes were evident during intense heat stress. Overall, the study established that amplitude of heat shock response and THI range for indicating severity of thermal stress for buffaloes are not in unison to cattle. The study also suggests skin temperature of the poll region could be used as non-invasive tool for monitoring heat stress in dairy buffaloes.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-021-01209-1.     

Reticulo-ruminal motility in cattle (Bos indicus) and water buffaloes (Bubalus bubalis) fed a low quality roughage diet

1. The effect of A and B sequence contractions of the reticulo-rumen on passage rate of digesta was compared in buffaloes and cattle fed low quality rhodes grass. 2. Both species ate the same amount per unit body weight but buffaloes spent 53% more time ruminating than cattle. 3. Buffaloes had fewer A and B sequence contractions each day and the rate of these contractions during eating, ruminating and at rest were slower. 4. A larger pool of fine feed particles in the rumen of buffaloes, generated by extra ruminating activity was associated with the 30% shorter mean residence time of particulate matter in the forestomach compared with cattle. 5. It is concluded that the difference in the number and frequency of contractions between the species was insufficient to affect passage rate of digesta from the stomach.     

Genetic variants of ribosomal DNA and mitochondrial DNA between swamp and river buffaloes

To clarify the genetic relationship between Swamp and River buffaloes, the restriction fragment length polymorphisms (RFLPs) of nuclear genomic ribosomal DNA (rDNA) and cytoplasmic mitochondrial DNA (mtDNA) were analysed. Blood or liver samples from 73 Swamp and three River buffaloes were collected in East and South-east Asian countries. DNA samples from cattle, goats and sheep were used for comparisons. The analysis of rDNA allowed water buffaloes, cattle, goats and sheep to be characterized by four distinct repeat-types. However, swamp and river buffaloes showed the same repeat-type. Divergence of water buffalo and cattle is considered to have occurred approximately four to six million years ago. The RFLPs for mtDNA divided water buffaloes into three haplotypes, swamp-1, swamp-2 and river types. Swamp-1 accounted for 91% of all swamp buffaloes while swamp-2 was observed only in water buffaloes from Thailand (9%). All river buffaloes were of the same haplotype. No differences were observed between swamp and river buffaloes at the rDNA level. In contrast, a few distinct differences between them were found at the mtDNA level. Therefore, mtDNA polymorphisms provide an adequate means for classifying water buffaloes into either swamp or river buffaloes.     

Molecular prevalence of different genotypes of Theileria orientalis detected from cattle and water buffaloes in Thailand

Here we report on an epidemiological study regarding the molecular prevalence of different genotypes of Theileria orientalis present among domestic cattle and water buffalo populations bred in Thailand. A phylogenetic analysis based on the parasitic gene encoding a major piroplasm surface protein revealed the presence of 5 genotypes (Types 1, 3, 5, 7, and N-3) in cattle and 7 genotypes (Types 1, 3, 4, 5, 7, N-2, and N-3) in water buffaloes. Types 4, 7, and N-3 of T. orientalis were reported for the first time in water buffaloes. The previously reported C and Thai types from Thailand clustered as types 7 and 6, respectively, in the present analysis. Great similarities were observed among nucleotide sequences of isolates of the same genotype from cattle and water buffaloes, and, therefore, water buffaloes were considered to serve as a reservoir for these genotypes of T. orientalis in Thailand. In conclusion, T. orientalis parasites circulating in Thailand are more diverse in their genetic characters than previously anticipated.     

Identification of Cu/Zn superoxide dismutase in cattle and river buffaloes

All air-living organisms produce superoxide dismutase (SOD) and several antioxidant enzymes that limit oxidative stress by detoxifying reactive oxygen species. SOD1 gene has been investigated in Egyptian native cattle and buffalos at the level of genomic DNA and cDNA that were extracted from leucocytes. An unexpected band at approximately 370 bp was obtained in cattle genomic DNA and cDNA as well as in buffalo cDNA. SOD1 amplified sequence of native cattle genomic DNA and cDNA showed a 93% alignment. Native cattle genomic DNA SOD1 amplicon shares sequence homology with mRNAs of Bos taurus “similar to superoxide dismutase” (SOD1) sequence of the GeneBank database. It also shares sequence homology with “similar to superoxide dismutase” on B. taurus chromosome BTA13. The results indicate that the genomic DNA of Egyptian native cattle contains SOD1 processed pseudo gene. SOD1 primers amplified three fragments in buffalo genomic DNA which indicates that buffalo genome has different copies of SOD1 due to alternative splicing. It failed to produce the 370 bp fragments found in cattle DNA. The protein analysis revealed no differences between Egyptian native cattle and B. taurus SOD1 mRNA. However, one amino acid, aspartic acid (Asp), in Egyptian native cattle and B. taurus SOD1, is substituted with asparagine (Asn) (D26N) in buffaloes. This amino acid substitution may be due to non-synonymous single nucleotide polymorphisms (nsSNPs). The nsSNPs detected in buffaloes may affect the function of the encoded protein. This study is the first investigation reporting that the resistance of the buffalo to diseases and parasites that afflict cattle may not be acquired but may have a genetic basis.     

Point prevalence of gastrointestinal helminthiasis in ruminants in southern Punjab, Pakistan

The present study was carried out to determine the prevalence of gastrointestinal helminthiasis in ruminants in an irrigated area of lower Punjab (Pakistan). For this purpose, 100 faecal samples were collected from sheep, goats, cattle and buffaloes. Parasitological procedures including direct and indirect methods (sedimentation and floatation) and coproculture were used for the identification of helminths. The overall prevalence of helminthiasis was 51% in cattle, 47% in buffaloes, 62% in sheep and 52% in goats, with nematodes being the most common helminths. The prevalence of helminths was higher in young animals compared with adults in cattle (P < 0.0001), buffaloes (P < 0.0001), sheep (P < 0.059) and goats (P = 0.010). The prevalence of different species of helminths also varied in different age groups, with Toxocara vitulorum being higher in calves than adults both in cattle (P = 0.017) and buffaloes (P < 0.0001). Sex-wise prevalence of helminths was higher in males than females for buffaloes (P < 0.0001) and sheep (P = 0.014) in contrast to cattle and goats.     

Point prevalence of bovine fascioliasis and the influence of chemotherapy on the milk yield in a lactating bovine population from the district of Toba Tek Singh, Pakistan

This paper provides an estimation of the point prevalence of fascioliasis and its economic impact in terms of increased milk yield after chemotherapy of a bovine population from the district of Toba Tek Singh, Punjab, Pakistan. A total of 2400 cattle and buffaloes were examined quantitatively using the McMaster egg-counting technique. Infected cattle and buffaloes (50 of each) were randomly selected and each divided into two groups of 25 animals. Groups A (buffaloes) and C (cattle) were treated with oxyclozanide (orally, 16.6?mg?kg-?1 body weight). Groups B and D served as negative controls for buffaloes and cattle, respectively. Pre- and post-treatment milk yield was recorded to determine if there were any changes in milk yield after treatment. Of 2400 faecal samples analysed, 654 (27.25%) were positive for Fasciola spp. with a mean number of eggs per gram (EPG) of 503.2. The point prevalence and worm burden of fascioliasis was significantly higher (OR?=?2.13; P?相似文献   

Treatment and reinfection of water buffaloes and cattle infected with Schistosoma japonicum in Yangtze River Valley, Anhui province, China

The aim of the present study was to evaluate the efficacy of praziquantel treatment of Schistosoma japonicum infections in cattle and water buffaloes and to assess the natural rate of reinfection after treatment. The studies were conducted on 2 islands in the Yangtze River, Anhui province, China, from March 2003 to January 2004. The efficacy of praziquantel was 97% when applied orally wrapped in tree leaves at the recommended doses. The efficacy was measured using a miracidium hatching technique on fecal samples collected 20 days after treatment. The treatment did not give rise to any major side effects. Reinfection after treatment was high and occurred throughout the year in both cattle and water buffaloes. Age-related resistance was only observed in water buffaloes. It is concluded that although praziquantel is highly effective against S. japonicum in cattle and water buffaloes, a single annual treatment strategy does not effectively control transmission. New strategies for integrated control of animal schistosomiasis are needed to control schistosomiasis transmission more effectively in farm areas of China.     

Risk factor analysis for the prevalence of gastrointestinal parasites found in large ruminants in Lower Dir Khyber Pakhtunkhwa Pakistan

The present study was designed to investigate the prevalence of gastrointestinal (GI) parasites in cattle and buffaloes of Lower Dir Khyber Pakhtunkhwa, Pakistan. The presence of the eggs, cysts, and oocysts of GI parasites in fecal samples were detected using direct smear methods and concentration techniques including floatation, centrifugation, and sedimentation. Identification of recovered fecal stages were determined by morphology using size and appearance of the recovered eggs, cysts, and oocysts. A total of 314 fecal samples were collected from the different Tehsils (Administrative Districts) and analyzed through microscopy. A higher prevalence was observed in the buffalo than the cow population. A total of 184 samples were positive for GI parasites of which 109/196 (55.61%) were from cattle, whereas 75/118 (63.55%) were from buffaloes. The minimum number of strongyle eggs detected in all the samples were 136.39 eggs/g (EPG). The mean EPG in cattle was 143.30 and 122.56 in buffaloes. The open-source water prevalence of GI parasites was higher than the other sources in cattle and the second highest after tap water in buffaloes. The seasonal prevalence of GI parasites ranged from 32.39% (23/71), in spring to 68.8% (86/125) in summer in cattle. In was For buffaloes the infection prevalence was 52.94% (27/51) and 71.64% (48/67) in spring and summer, respectively. Gastrointestinal parasites are a serious problem in cattle and buffaloes in the lower district of Dir Khyber Pakhtunkhwa Pakistan. In general, the burden of parasitic infection was low in most animals that received previous anti-parasitic treatment.     

Quality of handling and holding yard environment, and beef cattle temperament: 2. Consequences for stress and productivity

This experiment assessed the effects of different quality and quantity of handling and quality of the holding yard environment on the productivity and physiological parameters indicative of stress in beef cattle. One-hundred-and-forty-four steers were given one of three human handling and yarding experiences on six occasions during a 12-month grazing period post-weaning (backgrounding): Good handling/yarding, Poor handling/yarding and Minimal handling/yarding. At the end of this phase the cattle were lot-fed for 78 days, with no handling/yarding treatments imposed, before being transported for commercial slaughter. Temperament was assessed by flight speed (FS) and a fear of humans (FOH) test, which measured the proximity to a stimulus person (ZA), the closest approach to the person (CA) and the amount the cattle moved around the test arena (TT). Mid-way through backgrounding, the Minimal treatment group was heavier than the Good, which was heavier than the Poor (mean weights 207, 201 and 194 kg, respectively; P = 0.05; LSD = 5.4), but by the end of backgrounding there was no difference between treatments and treatment did not affect liveweight during lot-feeding. At the end of backgrounding, plasma cortisol levels were significantly lower (P < 0.001) in the Good treatment group compared to the Poor and Minimal groups but at the end of lot-feeding there was no significant difference between the groups. Treatment affected plasma non-esterified fatty acid levels in backgrounding (P = 0.060) and lot-feeding (P = 0.046) with levels being higher in the Minimal than the Good and Poor groups (backgrounding: 0.52, 0.44 and 0.47 nmol/L, respectively; SE 0.02; lot-feeding: 0.46, 0.41 and 0.41 mmol/L, respectively; LSD = 0.05). Significant weak to moderate (r-value <0.50) negative correlations were found between FS and average daily gain, but there were no consistent correlations between measures from the FOH test and productivity. FS and TT were weakly positively correlated with plasma l-lactate, glucose and cortisol levels, and CA was weakly to moderately negatively correlated with l-lactate and glucose levels. The results indicate that, whilst being imposed, the Good treatment reduced stress and the Poor treatment negatively impacted on liveweight gain. Minimal handling/yarding appeared to cause the cattle to experience stress, perhaps because of the relative novelty of being handled and confined. This work also confirms previous findings that cattle with high FS have poorer liveweight gains under both pasture and feedlot conditions and FS has some value as a predictor of productivity. Correlations also indicated that agitated cattle show a heightened arousal and stress responses when being handled. Fear of humans, as assessed by ZA, CA and TT, did not adversely affect productivity.     

Two Different Macaviruses,ovine herpesvirus-2 and caprine herpesvirus-2, Behave Differently in Water Buffaloes than in Cattle or in Their Respective Reservoir Species

The ongoing global spread of “exotic” farm animals, such as water buffaloes, which carry their native sets of viruses, may bear unknown risks for the animals, into whose ecological niches the former are introduced and vice versa. Here, we report on the occurrence of malignant catarrhal fever (MCF) on Swiss farms, where “exotic” water buffaloes were kept together with “native” animals, i.e. cattle, sheep, and goats. In the first farm with 56 water buffaloes, eight cases of MCF due to ovine herpesvirus-2 (OvHV-2) were noted, whereas additional ten water buffaloes were subclinically infected with either OvHV-2 or caprine herpesvirus-2 (CpHV-2). On the second farm, 13 water buffaloes were infected with CpHV-2 and two of those succumbed to MCF. In neither farm, any of the two viruses were detected in cattle, but the Macaviruses were present at high prevalence among their original host species, sheep and goats, respectively. On the third farm, sheep were kept well separated from water buffaloes and OvHV-2 was not transmitted to the buffaloes, despite of high prevalence of the virus among the sheep. Macavirus DNA was frequently detected in the nasal secretions of virus-positive animals and in one instance OvHV-2 was transmitted vertically to an unborn water buffalo calf. Thus, water buffaloes seem to be more susceptible than cattle to infection with either Macavirus; however, MCF did not develop as frequently. Therefore, water buffaloes seem to represent an interesting intermediate-type host for Macaviruses. Consequently, water buffaloes in their native, tropic environments may be vulnerable and endangered to viruses that originate from seemingly healthy, imported sheep and goats.     

黄牛、水牛体内人肉孢子虫18S rRNA基因研究及虫种鉴定

本文对自然感染的水牛源的人肉孢子虫以及黄牛源人孢子虫ＤＮＡ的１８Ｓ ｒＲＮＡ基因的ＰＣＲ扩增产物进行了测序。对年获的８６３ｂｐ的１８Ｓ ｒＲＮＡ基因分析比较表明,二者有较高的同源性,因此认为二者可能同是一种肉孢子虫－－人肉孢子虫（Ｓａｒｃｏｃｙｓｔｉｓ ｈｏｍｉｎｉｓ Ｒａｉｌｌｉｅｔ ａｎｄ Ｌｕｃｅｔ,１８９１）。由此推断,不仅黄牛可作为人肉孢子虫的中间宿主,水牛也可作为人肉孢子虫的中间宿主。     

Genomic diversity and selection sweeps identified in Indian swamp buffaloes reveals it's uniqueness with riverine buffaloes

The present investigation was focused to study genomic diversity of Indian swamp buffalo populations through reduced representation approach (ddRAD). The heterozygosity (F_ST) among the swamp buffaloes was 0.11 between Assam and Manipuri; 0.20 between swamp (Manipuri) and riverine buffaloes; 0.30 between swamp (Manipuri) and cattle. The average observed and expected heterozygosity in swamp buffalo populations was 0.254 and 0.221 respectively. The Inbreeding coefficient (F_IS) value was 0.02 among the swamp buffaloes. PCA and structure analysis revealed Manipuri swamp buffalo was genetically distinct and closely related to Nagaland swamp buffalo and least to Assam swamp buffalo. Identification of selective sweeps revealed 1087 regions to have undergone selection related to immune response, adaptation and nervous system. A total of 3451 SSRs were identified in the genome of swamp buffaloes. The study evidenced the genomic diversity in the swamp buffalo populations and its uniqueness in comparison with riverine buffalo and cattle.     

Validation of a sensitive enzymeimmunoassay for 13,14-dihydro-15-keto-PGF2alpha in buffalo plasma and its application for reproductive health status monitoring

A simple, sensitive and direct enzymeimmunoassay (EIA) procedure on microtitre plates using the second antibody coating technique was standardized and validated for the determination of 13,14-dihydro-15-keto PGF2alpha (PGFM) in unextracted buffalo plasma. The assay was carried out directly in 20 microl of buffalo plasma. PGFM standards prepared in charcoal stripped hormone-free plasma were used. The sensitivity of the assay was 0.4 pg/well, which corresponded to 20 pg/ml plasma. Plasma volumes for the assay ranging from 10 to 50 microl did not influence the PGFM standard curve; however, a slight drop in the OD450 was observed with higher plasma volumes. Biological validation of the assay was carried out in buffalo plasma samples obtained during physiological states of cyclicity, peri-estrus, post-insemination, reproductive tract infection and persistent corpus luteum conditions. A pulsatile pattern of plasma PGFM release was observed prior to estrus when PGFM was determined in blood samples collected at hourly intervals of time. The PGFM pulsatility was not observed when blood sampling frequency of either 4 or 12 h was considered. The PGFM levels stayed high in peripheral circulation of buffaloes with reproductive tract infections and remained low throughout the sampling period in buffaloes having persistent corpus luteum. After an initial increase post-insemination, the plasma PGFM levels showed minor fluctuations. The assay was found to be sufficiently reliable and specific for estimation of PGFM levels in buffaloes. The standardization and validation of PGFM assay in buffalo opens the prospects of using PGFM levels as an indicator for reproductive health status monitoring in this species.     

Seroprevalence of Neospora caninum antibodies in cattle and water buffaloes in India

Neospora caninum is now recognized as a major cause of abortion in cattle worldwide, but there is no report of N. caninum infection in cattle in India. Serum samples from 427 dairy cattle and 32 dairy water buffaloes from 7 organized dairy farms located in Punjab, India, were tested for N. caninum antibodies using a commercial monoclonal antibody-based competitive enzyme-linked immunosorbent assay (ELISA). Antibodies to N. caninum were found in 35 of 427 cattle from 6 of the 7 farms; 9.6% of cows, 5.1% of heifers, and 5.0% of calves were seropositive, suggesting postnatal transmission of N. caninum on the farm. Antibodies to N. caninum were found in 16 of 32 buffaloes tested from 2 dairy farms. In total, 64 cattle and 16 buffalo sera already tested by ELISA were also evaluated by an indirect fluorescent antibody test (IFAT) to verify ELISA results. Of the 64 cattle samples, 29 sera were negative by both tests and of the 35 ELISA-positive sera, 12 had IFAT titers of 1:100 or higher (1 had IFAT titer of 100, 2 had IFAT titer of 200, and 9 had IFAT titers of 400 or higher). Of the 16 buffalo sera positive by ELISA, 1 had an IFAT titer of 1:400. Thus, antibodies to N. caninum were demonstrated in cattle sera by 2 serologic methods. To our knowledge this is the first report of N. caninum infection in cattle and buffaloes in India.     

Karyotypic evolution of ribosomal sites in buffalo subspecies and their crossbreed

Domestic buffaloes are divided into two group based on cytogenetic characteristics and habitats: the “river buffaloes” with 2n = 50 and the “swamp buffaloes”, 2n = 48. Nevertheless, their hybrids are viable, fertile and identified by a 2n = 49. In order to have a better characterization of these different cytotypes of buffaloes, and considering that NOR-bearing chromosomes are involved in the rearrangements responsible for the karyotypic differences, we applied silver staining (Ag-NOR) and performed fluorescent in situ hybridization (FISH) experiments using 18S rDNA as probe. Metaphases were obtained through blood lymphocyte culture of 21 individuals, including river, swamp and hybrid cytotypes. Ag-NOR staining revealed active NORs on six chromosome pairs (3p, 4p, 6, 21, 23, 24) in the river buffaloes, whereas the swamp buffaloes presented only five NOR-bearing pairs (4p, 6, 20, 22, 23). The F1 cross-breed had 11 chromosomes with active NORs, indicating expression of both parental chromosomes. FISH analysis confirmed the numerical divergence identified with Ag-NOR. This result is explained by the loss of the NOR located on chromosome 4p in the river buffalo, which is involved in the tandem fusion with chromosome 9 in this subspecies. A comparison with the ancestral cattle karyotype suggests that the NOR found on the 3p of the river buffalo may have originated from a duplication of ribosomal genes, resulting in the formation of new NOR sites in this subspecies.     

Attenuation of luteolytic response following fish meal supplementation in dairy buffaloes (Bubalus bubalis)

Luteolysis of corpus luteum, due to un-inhibited PGF(2α) secretion, has been reported to be a cause of early embryonic mortality in dairy animals. The objective of this study was to determine the effects of fish meal (FM) supplementation on the uterine secretion of PGF(2α) and hence establish its supplementation as an antiluteolytic strategy in dairy buffaloes. Five cycling Murrah buffaloes were supplemented with 250g FM daily for 55 days in addition to their routine feed and seven buffaloes were kept as non-supplemented control. After 30 days of FM supplementation, the oestrus was synchronized in all the buffaloes using Ovsynch protocol. On day 15 of synchronized cycle, animals were challenged with oxytocin (OT; 100IU) intravenously and blood samples were collected at 15min interval, 1h before to 4h after OT challenge. The PGF(2α) response was measured as the venous concentration of 13,14-dihydro-15-keto PGF(2α) (PGFM). The mean hourly concentration of PGFM in FM supplemented buffaloes was lower than in the control buffaloes at all the occasions. During peak response (1h post-OT challenge), PGFM concentration was significantly lower (P<0.05) in FM supplemented buffaloes than in the control (197.4±41.7pg/ml versus 326.3±33.5pg/ml, respectively). Also the percent rise in PGFM after OT-challenge in FM supplemented buffaloes was less than the control (11.73% versus 22.47%). The dietary supplementation did not affect the size of corpus luteum (CL) and plasma progesterone concentration. Plasma glucose and total protein concentrations remained within the normal physiological limits during FM supplementation. The present study indicated that supplementing FM decreased the concentrations of PGF(2α) without alterations in the size of CL and plasma progesterone concentrations in dairy buffaloes.     

Impact of pre-ovulatory follicle diameter on plasma estradiol, subsequent luteal profiles and conception rate in buffalo (Bubalus bubalis)

The present study was designed to investigate the impact of pre-ovulatory follicle (POF) diameter on the day of estrus on plasma estradiol concentration, subsequent luteal profile (corpus luteum, CL, diameter and plasma progesterone concentration) and conception rate in buffaloes. Twenty-eight buffaloes were synchronized with synthetic analogue of prostaglandin F(2α) (PGF(2α)) administered 11 days apart. Transrectal ultrasonography and jugular vein blood sampling was carried out on the day of estrus and on days 0 (day of ovulation), 5, 12, 16 and 21 post-ovulation. Out of 28 buffaloes, 11 (39.3%) were diagnosed pregnant on day 40 post-ovulation. Retrospective analysis revealed that the buffaloes getting pregnant had larger (p<0.05) POF diameter. In fact, all the buffaloes (n=5/5) having POF diameter between >14 and 16 mm conceived, whereas, conception rate in buffaloes with POF diameter between >12 and ≤14 mm (n=6/17) or <12 mm (n=0/6) was 35.3% and 0.0%, respectively. A positive correlation (r=0.57, p<0.05) was observed between POF diameter and plasma estradiol concentration at estrus. On day 5 post-ovulation, luteal profile was positively correlated (CL: r=0.34, p<0.05; plasma progesterone concentration: r=0.27, p>0.05) with POF diameter. Further, on the same day, plasma progesterone concentration was positively correlated (r=0.47, p<0.05) with CL diameter, however, this correlation was absent (r=0.05, p>0.05) during the subsequent luteal phase. Nevertheless, the post-ovulation luteal profile of pregnant buffaloes was higher (p<0.05) compared to non-pregnant counterparts. In conclusion, the diameter of POF in buffaloes has positive impact on plasma estradiol concentration at estrus, post-ovulation luteal profile and conception rate. The diameter of CL can be used as an indicator of luteal function at early but not at mid or late luteal phase of estrus cycle in buffaloes.     

Identification of Sarcocystis hominis-like (Protozoa: Sarcocystidae) cyst in water buffalo (Bubalus bubalis) based on 18S rRNA gene sequences

DNA templates were extracted from isolates of Sarcocystis hominis-like cysts collected from cattle and water buffalo, as well as from Sarcocystis fusiformis cysts and Sarcocystis suihominis cysts. The 18S rRNA genes were amplified using DNA from a single cyst as the templates. Approximately 1,367-1,440 bp sequences were obtained. The sequence difference in isolates of Sarcocystis hominis-like cysts from water buffaloes, and isolates of S. hominis cysts from cattle were very low, only about 0.1%, much lower than the lowest value (1.7%) among different species. Combined with their morphological structure, these sequence data indicate that the 4 isolates from cattle and water buffalo might be the same species, i.e., S. hominis, suggesting that both cattle and water buffalo may serve as the intermediate hosts for this parasite. Apparently, this is the first report using a single cyst to do such work and is a useful way to distinguish the Sarcocystis cyst in an intermediate host that may be simultaneously infected by several different Sarcocystis species.