Fertility of Bos indicus and Bos indicus x Bos taurus crossbreed cattle after estrus synchronization

Ninety-five cows (79 Boran and 16 Boran-Brahman crossbreeds) and 107 heifers (55 Boran and 52 Boran x Friesian F1 crossbreeds) were used to determine estrus response, estrus response interval and pregnancy rate following synchronization with prostaglandin (PGF(2)alpha), a progesterone-releasing intravaginal device (PRID) and Synchro-mate B (SMB). The proportion of cattle responding to synchronization treatment was 62.5, 43.5 and 57.7% for cows and 85.7, 68.0 and 81.5% for heifers using PGF(2)alpha, PRID and SMB, respectively. The overall mean response was 59 and 81.8% for cows and heifers, respectively. The estrus response of the control animals over a 45-d breeding period was 72.7 and 90% for cows and heifers, respectively. The estrus response interval for cows was 31.8, 22.1 and 18.0 h and it was 51.1, 38.0 and 21.6 h for heifers with PGF(2)alpha, PRID and SMB treatment, respectively. Mean pregnancy rate for cows was 50.0, 34.8, 46.2 and 68.8% and for heifers it was 60.7, 40.0, 55.6 and 77.8% in the PGF(2)alpha, PRID, SMB and control groups, respectively. Based on these findings, it was concluded that both PGF(2)alpha and SMB produce a satisfactory estrus response and pregnancy rate in the cattle studied.     

Estimate of the population of preantral follicles in the ovaries of Bos taurus indicus and Bos taurus taurus cattle

The number of oocytes recovered from Bos taurus indicus females subjected to ovum pick-up averaged two to four times greater compared to Bos taurus taurus females. The objective of the present study was to test the hypothesis that this difference in oocyte yield was due to more preantral follicles in the ovaries of Bos indicus females. Ovaries (n = 64) from Nelore (Bos indicus) fetuses (n = 10), heifers (n = 12), and cows (n = 10), and Aberdeen Angus (Bos taurus) fetuses (n = 10), heifers (n = 12), and cows (n = 10) were cut longitudinally into halves, fixed, and processed for histological evaluation. The number of preantral follicles was estimated by counting them in each histological section, using the oocyte nucleus as a marker and employing a correction factor. The average number of preantral follicles in the ovaries of Bos indicus vs Bos taurus was (mean ± SD) 143,929 ± 64,028 vs 285,155 ± 325,195 for fetuses, 76,851 ± 78,605 vs 109,673 ± 86,078 for heifers, and 39,438 ± 31,017 vs 89,577 ± 86,315 for cows (P > 0.05). The number of preantral follicles varied greatly among individual animals within the same category, as well as between breeds. In conclusion, we inferred that the higher oocyte yield from Bos indicus females was not due to a greater ovarian reserve of preantral follicles. Therefore, mechanisms controlling follicle development after the preantral stage likely accounted for differences between Bos indicus and Bos taurus females in number of oocytes retrieved at ovum pick-up.     

Ciliate protozoa in the rumen of Kenyan zebu cattle, Bos taurus indicus, with the description of four new species

The composition of the fauna of rumen ciliates in zebu cattle in Kenya was surveyed and 13 genera containing 51 species with 19 formae were identified. Four new species were recognized, then described as Diplodinium africanum n. sp., Diplodinium namum n. sp., Eudiplodinium kenyensis n. sp., and Ostracodinium iwawoi n. sp. In addition, Buetschlia triciliata and Ostracodinium stokyi were found for the second and third times and described as Hsiungia triciliata n. comb. and Enoploplaston stokyi n. stat., with two formae, respectively. The species composition was similar to that of Indian zebu but several species were considered to originate from African native ruminants. In the percentage composition of genera, the numbers of Entodinium, which normally predominate in rumens in other areas, were very low.     

Influence of the breed of bull (Bos taurus indicus vs. Bos taurus taurus) and the breed of cow (Bos taurus indicus, Bos taurus taurus and crossbred) on the resistance of bovine embryos to heat

In vitro studies have shown that Bos taurus indicus (B. t. indicus) embryos submitted to heat shock at early stages of development are better able to survive as compared to Bos taurus taurus embryos. Embryo genotype influences resistance to heat shock thus leading to the question as to whether embryos sired by thermo-tolerant breeds exhibit the same resistance to heat shock. In the present study the influence of both oocyte and semen, on the resistance to heat shock (HS) at early stages of in vitro development, was assessed in B. t. indicus [Nelore (N) breed], B. t. taurus [Holstein (H) and Angus (A) breeds] and crossbreds. In Experiment 1, Nelore and crossbred oocytes were collected from slaughterhouse ovaries and fertilized with spermatozoa from Nelore and Angus bulls. Presumptive embryos were collected and randomly assigned to control (39 degrees C) or HS at 12, 48 or 96 h post insemination (hpi; 41 degrees C for 12h) treatments. The cleavage rates and proportion of embryos developing to the blastocyst and hatched blastocyst stages were recorded on Days 2, 8 and 10, respectively. Heat shock treatment decreased development of both Nelore and crossbred embryos. There was a significant interaction between time (12, 48 or 96 hpi) and temperature for blastocyst rates, i.e., the embryos became more thermotolerant as development proceeded. In Experiment 2, oocytes from Nelore and Holstein cows were fertilized with semen from bulls of either Nelore or Angus breeds, and subjected to 12 h HS at 96 hpi. Heat shock at 96 hpi, decreased embryo development. Additionally, cowxtreatment and bullxtreatment interactions were significant for blastocyst rates, i.e., both breed of cow and breed of bull affected the decline in blastocyst rate caused by heat shock treatment. In conclusion, the present results indicate that Nelore embryos (indicus) are more resistant to heat shock than Holstein (taurus) at early stages of in vitro development, and that embryos become more thermo-tolerant as development proceeds. Additionally, the resistance to heat shock was a result of the genetic contribution from both oocyte and spermatozoa.     

Comparative gene frequencies of nucleoside phosphorylase from cattle of Bos taurus and Bos indicus derivation in Brazil

1. Two nucleoside phosphorylase (NP) phenotypes were detected in 844 animals from four distinct genetic groups of Bos taurus and Bos indicus derivation. 2. Bos indicus breeds like Guzerat (Kankrej), Gir, Nellore (Ongole) and Indubrazil presented an NP-H frequency of 1.00, 0.928, 0.776 and 0.754 respectively, while the Canchim breed, a Bos taurus-Bos indicus crossbred cattle (5/8 Charolais-3/8 Zebu) presented a frequency of 0.372. 3. The high frequency detected from the NP-H allele in the Bos indicus breeds strongly suggests that this enzyme is a genetic marker for cattle and that it probably has a very high frequency in all Indian breeds.     

Synaptonemal complex analysis of hybrid cattle. II. Bos indicus x Bos taurus F1 and backcross hybrids

The levels of meiotic chromosome pairing abnormalities observed in six Australian F1 Bos indicus x Bos taurus cattle crosses (mean = 23%) were significantly higher than those of the full-blood breeds (9%). The abnormal configurations in the F1 hybrids included partial pairing failure, multivalents, interlocks, and inversion pairing. Abnormal configurations were also present, but at lower frequency, in backcross hybrid bulls. The main types of abnormal configurations and the levels of XY-autosomal associations and autosomal asynapsis observed were unlikely to cause significant fertility problems in the hybrids.     

Cryptosporidium bovis n. sp. (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus)

A new species of Cryptosporidium, C. bovis, is described. Oocysts of C. bovis, previously identified as Cryptosporidium genotype Bovine B (GenBank AY120911), are morphologically indistinguishable from those of C. parvum. They are excreted fully sporulated and contain 4 sporozoites, but lack sporocysts. Oocysts measure 4.76-5.35 microm (mean = 4.89 microm) x 4.17-4.76 microm (mean = 4.63 microm), with a length-to-width ratio of 1.06 (n = 50). Oocysts were not infectious for neonatal BALB/ c mice, but were infectious for 2 calves that were previously infected with C. parvum. Oocysts were not infectious for 2 experimentally exposed lambs less than 1 wk of age and were not detected in 42 lambs 2-3 mo of age, but were detected in a 2-wk-old lamb. In an earlier study, 79 of 840 calves on 14 dairy farms in 7 states were found infected with the new species. Most calves were 2-7 mo of age and none exhibited signs of diarrhea. This new species has been found in 10 of 162 calves aged 9 to 11 mo on a beef farm in Maryland. Fragments of the 18S rDNA, HSP-70, and actin genes were amplified by PCR, and purified PCR products were sequenced. Multilocus analysis of the 3 unlinked loci demonstrated the new species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further evidence of species status. Based on these biological and molecular data, we consider this highly prevalent Cryptosporidium that infects primarily postweaned calves to be a new species and propose the name Cryptosporidium bovis n. sp. for this parasite.     

Coexistence of Bos taurus and B. indicus mitochondrial DNAs in nuclear transfer-derived somatic cattle clones

We investigated the mitochondrial DNA (mtDNA) composition in one of the largest adult somatic mammalian clones (n = 20) reported so far. The healthy cloned cattle were derived from nuclear transfer of an identical nuclear genetic background (mural granulosa donor cells including surrounding cytoplasm) into enucleated oocytes with either Bos indicus or B. taurus mtDNA. Here we report the first cases of coexisting mtDNAs of two closely related subspecies following nuclear transfer. Heteroplasmy (0.6-2.8%) was found in 4 out of 11 cross-subspecies cloned cattle. Quantitation was performed using "amplification refractory mutation system (ARMS) allele-specific real-time PCR." We determined that the ratio of donor cell to recipient cytoplast mtDNA copy number was 0.9% before nuclear transfer. Therefore, we concluded that the percentage of donor cell mtDNA in the heteroplasmic intersubspecific cloned animals is in accordance with neutral transmission of donor mtDNA. We determined an amino acid sequence divergence of up to 1.3% for the two subspecies-specific mtDNA haplotypes. In addition, intrasubspecific B. indicus heteroplasmy of approximately 1% (but up to 7.3 and 12.7% in muscle and follicular cells of one animal) was detected in 7 out of the 9 B. indicus intrasubspecific cloned cattle.     

Morphology and infraciliature of two new marine urostylid ciliates: Metaurostylopsis struederkypkeae n. sp. and Thigmokeronopsis stoecki n. sp. (Ciliophora, Hypotrichida) from China

ABSTRACT. The morphology and infraciliature of two new marine urostylid ciliates, Metaurostylopsis struederkypkeae n. sp. and Thigmokeronopsis stoecki n. sp., collected from the coastal waters off Qingdao (Tsingtao), China, have been investigated. Metaurostylopsis struederkypkeae n. sp. is characterized by the slender body shape, small size, rose-reddish cell colour, and having two kinds of pigment-like granules. The larger pigment-like granules are yellow–green or grass-green in colour, oval in shape, and flattened, whereas the smaller ones are wine-reddish. Infraciliature and nuclear apparatus are similar to the well-known Metaurostylopsis marina. Thigmokeronopsis stoecki n. sp. is characterized by its large size with dark brown cell colour and grass-green cortical granules, which are large, blood-cell shaped, and sparsely distributed. The thigmotactic ciliature is conspicuous: 11–14 rows of densely arranged cirri occupy the most postoral area. Keys are provided for all the known species in both genera.     

Effects of scrotal insulation on sperm production,semen quality,and testicular echotexture in Bos indicus and Bos indicus x Bos taurus bulls

The objectives of the present study were to evaluate the effects of scrotal insulation on sperm production, semen quality, and testicular echotexture in Bos indicus and Bos indicus x Bos taurus crossbred bulls. In one experiment, B. indicus bulls (n=12) were allocated to control and whole-scrotum insulation groups, while in a second experiment, crossbred bulls (n=21) were allocated into control, whole-scrotum, and scrotal-neck insulation groups. Insulation was applied for 4 days (start of insulation = Day 0) and semen collection and testicular ultrasonographic examinations were performed twice weekly until Day 35. Sperm concentration and total sperm output during the post-insulation period were greater in control groups, but significant differences were observed only in B. indicus bulls. Overall, sperm motility in scrotal-insulated B. indicus bulls was lower (P<0.05) than in the control group. After whole-scrotum insulation in crossbred bulls, sperm motility was lower (P<0.05) than pre-insulation levels between Days 21 and 31, and lower than control levels on Day 24. The proportion of normal sperm after whole-scrotum insulation was lower than pre-insulation and control values from Day 11 to the end of the experiment in B. indicus bulls (P<0.05 from Days 14 to 21 and on Day 27), and from Days 14 to 25 in crossbred bulls (P<0.05 on Days 14 and 18). Insulation of the scrotal neck in crossbred bulls did not significantly affect semen quality. Loose sperm heads (Day 11), midpiece defects (Days 11 and 14), and acrosome defects (Days 27 and 31) increased (P<0.05) in insulated B. indicus bulls, while proximal cytoplasmic droplets (Days 14, 18 and 27 in B. indicus; Days 24 and 27 in crossbred bulls) and sperm vacuoles (Days 18 and 21 in B. indicus; Day 18 in crossbred bulls) increased (P<0.05) in whole-scrotum insulation groups in both experiments. There was considerable variation among bulls in the incidence of specific sperm defects. The timing of appearance of sperm defects after insulation provided insights into the pathogenesis of specific abnormalities. Neither whole-scrotum nor scrotal-neck insulation affected testicular echotexture in either experiment. In conclusion, whole-scrotum insulation resulted in decreased sperm production and semen quality in B. indicus and B. indicus x B. taurus bulls, but those changes were not associated with changes in testicular echotexture.     

Comparative analysis of GDF 8 (myostatin) in Bos indicus and Bos taurus.

We report the myostatin gene sequence of Bos indicus cattle in comparison to Bos taurus. B. indicus genomic sequence was obtained by overlapping PCR amplification of genomic DNA. Exon splice sites were confirmed by mRNA sequencing. There were 5 exonic single nucleotide polymorphisms (SNP) only one of which was a non-synonymous mutation that resulted in a serine to asparagine (S214N) amino acid substitution. The B. indicus gene has two insertions of 16 and 12 bases in the first intron. In addition, SNPs in the 3' UTR and intronic regions are also reported.     

Microsatellite analysis of genetic population structure of zebu cattle (Bos indicus) breeds from north-western region of India

The present study aims to understand the existing genetic diversity and structure of six native cattle breeds (Rathi, Tharparkar, Nagori, Mewati, Gir, and Kankrej) adapted to the north-western arid and semi-arid region of India based on microsatellite loci. Various diversity estimates, mean number of alleles (12.84); effective number of alleles (5.02); gene diversity (0.769), and observed heterozygosity (0.667) reflected the existence of substantial within-breed diversity in all the investigated cattle breeds. Mean estimates of F-statistics: F(IT) = 0.144 ± 0.023, F(IS) = 0.071 ± 0.021, and F(ST) = 0.078 ± 0.014 were significantly different from zero (P < 0.05). The interbreed relationships indicated moderate level of breed differentiation between the six cattle breeds with least differentiation between Kankrej-Mewati pair. The phylogeny structuring further supported close grouping of Kankrej and Mewati breeds. Correspondence analysis plotted Rathi, Tharparkar, and Gir individuals into three separate areas of multivariate space; whereas, Kankrej, Mewati, and Nagori cattle showed low breed specific clustering. This reflected the existence of discrete genetic structure for Tharparkar, Rathi, and Gir, the prominent dairy breeds of the region; whereas, admixture was observed for Kankrej, Mewati, and Nagori individuals.     

Ciliate Protozoa in the Rumen of Kenyan Zebu Cattle,Bos taurus indicus,with the Description of Four New Species1

ABSTRACT. The composition of the fauna of rumen ciliates in zebu cattle in Kenya was surveyed and 13 genera containing 51 species with 19 formae were identified. Four new species were recognized, then described as Diplodinium africanum n. sp., Diplodinium nanum n. sp., Eudiplodinium kenyensis n. sp., and Ostracodinium iwawoi n. sp. In addition, Buetschlia triciliata and Ostracodinium stokyi were found for the second and third times and described as Hsiungia triciliata n. comb. and Enoploplastron stokyi n. stat., with two formae, respectively. The species composition was similar to that of Indian zebu but several species were considered to originate from African native ruminants. In the percentage composition of genera, the numbers of Entodinium, which normally predominate in rumens in other areas, were very low.     

Investigation of X- and Y-specific single nucleotide polymorphisms in taurine (Bos taurus) and indicine (Bos indicus) cattle

Initially, domesticated African cattle were of taurine type. Today, we find both African Bos taurus and Bos indicus cattle, as well as their crossbreeds, on the continent of Africa and they all share the same set of African taurine mitochondrial DNA haplogroups. In this study, we report genetic variation as substitutions and insertions/deletions (indels) on both the X and Y chromosomes, and use the variation to assess hybridization between taurine and indicine cattle. Six African cattle breeds (four Sanga breeds, including Raya Azebu, Danakil, Caprivi, Nguni; and two Zebu breeds, including Kilimanjaro Zebu and South Kavirondo Zebu) were screened for six new X-chromosomal markers, specifically three single nucleotide polymorphisms and three indels in the DDX3X (previously DBX ) and ZFX genes, and five previously identified Y-chromosomal markers in the DDX3Y (previously DBY ) and ZFY genes. In total, 90 (57 bulls and 33 cows) samples from the African breeds were analysed. We identify five diagnostic haplotypes of indicine and taurine origins on both the X and Y chromosomes. For each breed, the level of indicine introgression varies; in addition to pure taurine, indicine and hybrid X-chromosome individuals, recombinant X-chromosome variants were also detected. These markers are useful molecular tools for assessing the level of indicine admixture in African cattle breeds.     

Influence of bull biostimulation, season and parity on resumption of ovarian activity of zebu (Bos indicus) cattle following parturition

A total of 135 postpartum suckled zebu cows were assigned randomly at calving to two treatments: cows exposed to vasectomised bulls (Mature Bull Exposure, MBE) and cows not exposed to bulls (No Bull Exposure, NBE) for a period of 150 days postpartum. This study was conducted to determine the influence of bull biostimulation, season and parity on postpartum reproductive performance of Bos indicus cattle. The trials were conducted in two seasons: cows calving in the dry season and cows calving in the rainy season. Cows with an increase in serum progesterone (P(4)) concentration of >1 ng/ml from the weekly blood samples were used to analyse the number of days from calving to the time of resumption of ovarian activity. The introduction of vasectomised bulls shortened the postpartum anoestrus in cattle following calving. Mean interval from calving to resumption of ovarian activity for the MBE cows was 71.7 days, which was significantly earlier following calving than the NBE cows with a duration of 77.8 days. By 60 to 80 days postpartum, the proportion of cows at resumption of postpartum activity for MBE cows was greater than for the NBE cows.Mean interval from calving to resumption of ovarian activity for cows that calved in the dry season was 71.3 days, which was significantly earlier than for cows that calved in the rainy season (78.6 days). At 60 days postpartum, the proportion of cows at resumption of postpartum ovarin activity for cows that calved in the dry season was greater than the cows that calved in the rainy season. Mean interval from parturition to resumption of ovarian activity for cows with three to five calvings was 65.1 days, which was significantly earlier than the value of 71. 2 days for cows with one to two calvings. By 60 to 80 days postpartum, the proportion of cows at onset of ovarian activity for cows with three to five calvings was greater than those cows with one to two calvings. Cows that calved in the dry season completed uterine involution by 24.4 days, which was significantly shorter than the duration of 26.5 days for cows that calved in the rainy season. Cows with three to five calvings completed uterine involution earlier than those with one to two calvings. It is concluded that bull-cow biostimulation influences reproductive activity in the cow possibly through olfactory cues (pheromones).     

A polymorphism in randomly amplified DNA that differentiates the Y chromosomes of Bos indicus and Bos taurus

A small number of west African Bos taurus cattle breeds, including the N'Dama, constitute a valuable genetic resource by virtue of their ability to remain productive under trypanosomiasis challenge. However, introgression of Bos indicus genes into the trypanotolerant breeds, particularly by introduction of zebu bulls, is a threat to this resource. This work describes the characterization and cloning of a bovine randomly amplified polymorphic DNA (RAPD) that is generated in polymerase chain reaction (PCR) with the 10 base primer ILO1065 from Bos indicus male templates, but not from B. taurus male templates or female templates of either type. Male-specific sequences with homology to the RAPD also occur in B. taurus breeds. This suggests that the polymorphism may be due to base substitution(s) in an ILO1065 priming site, or insertion/deletion events either affecting priming sites or occurring between sites on the cattle Y chromosome. We have shown that cattle, whether of B. indicus or B. taurus phenotype, which possess a typically B. indicus metaphase Y chromosome on the basis of QFQ banding, have a B. indicus ILO1065-generated genotype. The ILO1065-primed RAPD can be used in a simple dot blot assay as a probe of RAPD-PCR products, to provide a convenient, reliable and effective means of detecting introgression of zebu genes in B. taurus cattle populations.     

Use of primers derived from a new sequence of the bovine Y chromosome for sexing Bos taurus and Bos indicus embryos

A bovine male-specific marker was identified in our laboratory through random amplified polymorphic DNA (RAPD) analysis. This fragment of 3216 bp was cloned, sequenced and mapped by fluorescent in situ hybridization (FISH) on the taurine Yq. Primers derived from this sequence were initially screened by polymerase chain reaction (PCR) for their ability to detect Y-specific segments in zebu and taurine genomic DNA. Two of these primers amplified a 655 bp Y-specific sequence present in taurine and zebu male genomic DNA. These primers were then used for detecting the 655 bp male sequence in DNA from 173 zebu and 30 taurine embryos, which had been previously sexed using primers for the sequence BC 1.2. The results revealed an accuracy of 100%.