The characteristics of the reproductive capacity of hybrids of banteng (Bos (Bibos) javanicus d'Alton) with the domestic cow (Bos (Bos) primigenius taurus)]

The hybrid progeny of F1 produced by crossing of banteng and domestic cow is characterized by absolute sterility of the male line and fertility of the female line. The crossbred males become fertile in further progenies while crossing cross-females with males of initial forms. Successful use of inter-subgenetic hybrids of banteng and domestic cow in selection work is hindered by pathological deviations in their genitals structure as well as frequent deaths of the embryos and foetus in hybrid cows at the different stages of embryogenesis. It is suggested that those deviations (both in cow and in bulls) are caused mainly by genetic and immunological factors and are determined to a greater extent by combination of parental couples.     

Inbreeding and population dynamics of the Chillingham cattle (Bos taurus)

The Chillingham herd of white cattle has been isolated and confined in a park in northern England for several centuries. Blood grouping confirmed the cattle to be remarkably homozygous. Random fixation of harmful alleles and consequent extinction have presumably been prevented by selection, and this paper discusses possible selective processes and the ways in which these have changed over the last hundred years. Herd records from 1862 to 1899 and 1953 to 1985 show that, in the former period, but not the latter, culling and castration took place. In both periods, breeding was not seasonal. Herd fertility (calves born per female) was higher in the latter period. Between 1953 and 1985, calves which survived for at least 12 months had a median date of birth (25 June) a month later than that of calves which did not survive. Conception intervals were rather longer and fecundity lower than those observed in commercial cattle. K-factor analysis showed mortality to differ in its causes between the sexes. A multiple regression model showed January-May rainfall, and population size on 1 January to influence mortality rate of the January-May period. The Chillingham cattle have evidently been, and continue to be, subjected to rigorous selection and this presumably underlies the survival of this herd.     

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.     

Identical marker alleles in Podolic cattle (Bos taurus) and Indian zebu (Bos indicus)

In the context of biochemical marker research and in order to add new information on native breeds, the present work focuses on a local Southern Italy cattle, namely Italian Podolic. We provide the complete structural characterisation of alpha-lactalbumins and beta-globin chains isolated from Podolic cattle (Bos taurus). Given the unavailability of the complete sequence for alpha-lactalbumin A of taurine cattle in the literature, we intended to check its structure in order to ascertain the absence of any possible silent mutation. Screening the Podolic cattle, we found a new beta-globin variant not detectable by conventional methods. The presence of such a new variant might be helpful in the study of the Podolic population genetic structure and for a better knowledge of the gene pool per se, and in comparison with the other breeds. Structural analyses showed that the new beta-globin Podolic variant exhibited the same sequence as beta-globin Azebu. The alpha-lactalbumin A was the same as that isolated from zebu cattle (Bos indicus). The results are discussed in relation to the possible involvement of the two markers in the debate on the origin of the Podolic breed.     

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.     

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.     

Skeletal muscle myosins from the yak (Bos grunniens), cattle (Bos taurus) and their hybrids

The skeletal muscle myosins of the yak (Bos grunniens), of cattle (Bos taurus) and of their first and second filial generation hybrids have been studied by ATPase measurements, fluorescence spectroscopy, near-ultraviolet circular dichroism and peptide mapping on polyacrylamide gels. The ATPase activities, the intrinsic tryptophan fluorescence enhancement upon addition of ATP and the circular dichroism spectra of the four myosins were closely comparable. Peptide maps of the myosin heavy chains indicate extensive sequence homologies but do reveal differences between the myosins of the yak and cattle.     

Superovulatory response of dairy cattle (Bos taurus ) in a tropical environment

Dairy (Bos taurus) heifers and cows (n = 40) in a tropical environment were treated during mid-luteal phase using either SUPER-OV(R) or OVAGEN to induce superovulatory response after synchronization of the superovulatory estrus with a synthetic progestagen and cloprostenol (PG). Estrous cattle were inseminated twice using frozen-thawed semen, and embryos were recovered nonsurgically, on-farm, 7 d later. Between initiation of gonadotrophin treatment and recovery of embryos, 4 blood samples per animal were collected from 26 animals for determination of plasma progesterone (P4) concentration. Two (5%), 28 (70%) and 10 (22%) of the animals were observed in estrus 1.5, 2 and 2.5 to 3 d after PG, respectively. There was no difference (P = 0.7) in the number of palpable CL between animals treated with SUPER-OV (7.6 +/- 1.0; n = 18) and those treated with OVAGEN (7.9 +/- 1.1; n = 22). There was also no significant difference (P > 0.05) between Jersey vs Ayrshire breeds or heifers vs cows in the ovarian response as estimated by the number of palpable CL. However, a higher proportion of Ayrshire cattle and donors treated with OVAGEN yielded a higher total number and viable/transferable embryos than Jersey and SUPER-OV-treated cattle. There was a significant (P < 0.05) correlation between the number of CL and total number of embryos (r = 0.65); the number of transferable embryos was also significantly related to the total number of embryos per recovery (r = 0.85; P < 0.05). For 15 animals with normal P4 profiles, the mean (+/-SEM) plasma P4 concentration was 14.4 +/- 0.8, 0.5 +/- 0.2, 5.4 +/- 1.1 and 39.4 +/- 3.0 nmol L at initiation of gonadotrophin treatment, superovulatory estrus and Days 3 and 7, respectively. The mean (+/-SEM) interval between a PG injection given after embryo recovery and the induced estrus was 7.1 +/- 0.7 d (range 3 to 14 d) and the length of the superovulatory cycle was 24.1 +/- 3.2 d (range 12 to 35 d).     

Isozyme characterization of cattle (Bos taurus) and American buffalo (Bison bison) cell cultures.

Four Bovidae cell lines (BEK-1, MDBK, Bu and EBTr) were characterized by means of enzymatic biochemical markers. Out of 15 enzymatic systems, 3--adenosine deaminase (Ada), phosphoglucomutase (Pgm) and nucleoside phosphorylase (Np)--were found to be polymorphic and quite suitable for biochemical identification of each cell line. The Bu cell line has shown a Np phenotypic pattern which could be distinctive of the Bison bison species.     

Localization of the fragile X chromosome break points in Holstein-Friesian cattle (Bos taurus)

Chromosome fragility is generally believed to affect cattle reproductive performance. Lymphocytes were cultured and the long arm of the X-chromosome was measured in 19 bovines that had been presented as repeat breeders, freemartin cotwins, or as having had anestrus or abortions. The positions of the break points on the X-chromosome were estimated by a measuring compass, starting at the centromere. Relative measurements were calculated from the ratio of break point distance from the centromere to the total Xq length. In our study the break points were found to be mainly in the middle of the long arm (X = 0.52; sigma=0.046). Giemsa banding showed that the break points were located in a large negative G-band observed in region 3 of the long arm. The relationship of these findings to animal reproductive problems is discussed.     

Localisation of aphidicolin-induced break points in Holstein-Friesian cattle (Bos taurus) using RBG-banding

Fragile sites (FS) seem to play a role in genome instability and may be involved in karyotype evolution and chromosome aberrations. The majority of common fragile sites are induced by aphidicolin. Aphidicolin was used at two different concentrations (0.15 and 0.30 μM) to study the occurrence of FS in the cattle karyotype. In this paper, a map of aphidicolin induced break points and fragile sites in cattle chromosomes was constructed. The statistical analysis indicated that any band with three or more breaks was significantly damaged (P < 0.05). According to this result, 30 of the 72 different break points observed were scored as fragile sites. The Pearson correlation test showed a positive association between chromosome length and the number of fragile sites (r = 0.54). On the contrary, 21 FS were identified on negative R bands while 9 FS were located on positive R bands.