Santa Gertrudis Cattle Research Articles

Allelic Variation in Protein Tyrosine Phosphatase Receptor Type-C in Cattle Influences Erythrocyte, Leukocyte and Humoral Responses to Infestation With the Cattle Tick Rhipicephalus australis.

The protein tyrosine phosphatase receptor type-C (PTPRC) gene encodes the common leukocyte antigen (CD45) receptor. CD45 affects cell adhesion, migration, cytokine signalling, cell development, and activation state. Four families of the gene have been identified in cattle: a taurine group (Family 1), two indicine groups (Families 2 and 4) and an African “taurindicine” group (Family 3). Host resistance in cattle to infestation with ticks is moderately heritable and primarily manifests as prevention of attachment and feeding by larvae. This study was conducted to describe the effects of PTPRC genotype on immune-response phenotypes in cattle that display a variable immune responsiveness to ticks. Thirty tick-naïve Santa-Gertrudis cattle (a stabilized composite of 5/8 taurine and 3/8 indicine) were artificially infested with ticks weekly for 13 weeks and ranked according to their tick counts. Blood samples were taken from control and tick-challenged cattle immediately before, then at 21 d after infestation and each subsequent week for 9 weeks. Assays included erythrocyte profiles, white blood cell counts, the percentage of cellular subsets comprising the peripheral blood mononuclear cell (PBMC) population, and the ability of PBMC to recognize and proliferate in response to stimulation with tick antigens in vitro. The cattle were PTPRC genotyped using a RFLP assay that differentiated Family 1 and 3 together (220 bp), from Family 2 (462 bp), and from Family 4 (486 bp). The PTPRC allele frequencies were Family 1/3 = 0.34; Family 2 = 0.47; Family 4 = 0.19. There was no significant association between PTPRC genotype and tick count. Each copy of the Family 1/3 allele significantly decreased total leucocyte count (WCC) and CD8+ cells. Increasing dosage of Family 2 alleles significantly increased red blood cell count (RCC), haematocrit (PCV), and haemoglobin (Hb) concentration in blood. Increasing dosage of the Family 4 allele was associated with increased WCC, reduced RCC, reduced PCV and reduced Hb. Homozygote Family 1/3 animals had consistently lower IgG1 in response to tick Ag than homozygote Family 2 animals. The PTPRC genotype influences the bovine immune response to ticks but was not associated with the observed variation in resistance to tick infestation in this study.

Serum proteomes of Santa Gertrudis cattle before and after infestation with Rhipicephalus australis ticks

Previous studies have applied genomics and transcriptomics to identify immune and genetic markers as key indicator traits for cattle tick susceptibility/resistance; however, results differed between breeds, and there is lack of information on the use of host proteomics. Serum samples from Santa Gertrudis cattle (naïve and phenotyped over 105days as tick-resistant [TR] or tick-susceptible [TS]) were used to conduct differential abundance analyses of protein profiles. Serum proteins were digested into peptides followed by identification and quantification using sequential window acquisition of all instances of theoretical fragment ion mass spectrometry. Before tick infestation, abundance of 28 proteins differed significantly (adjusted P<10-5 ) between TR and TS. These differences were also observed following tick infestation (TR vs TS) with a further eight differentially abundant proteins in TR cattle, suggesting possible roles in adaptive responses. The intragroup comparisons (TS-0 vs TS and TR-0 vs TR) showed that tick infestation elicited quite similar responses in both groups of cattle, but with relatively stronger responses in TR cattle. Many of the significantly differentially abundant proteins in TR Santa Gertrudis cattle (before and after tick infestation) were associated with immune responses including complement factors, chemotaxis for immune cells and acute-phase responses.

Estimation of genomic breed composition of individual animals in composite beef cattle.

Three statistical models (an admixture model, linear regression, and ridge-regression BLUP) and two strategies for selecting SNP panels (uniformly spaced vs. maximum Euclidean distance of SNP allele frequencies between ancestral breeds) were compared for estimating genomic-estimated breed composition (GBC) in Brangus and Santa Gertrudis cattle, respectively. Animals were genotyped with a GeneSeek Genomic Profiler bovine low-density version 4 SNP chip. The estimated GBC was consistent among the uniformly spaced SNP panels, and values were similar between the three models. However, estimated GBC varied considerably between the three methods when using fewer than 10000 SNPs that maximized the Euclidean distance of allele frequencies between the ancestral breeds. The admixture model performed most consistently across various SNP panel sizes. For the other two models, stabilized estimates were obtained with an SNP panel size of 20000 SNPs or more. Based on the uniformly spaced 20K SNP panel, the estimated GBC was 69.8-70.5% Angus and 29.5-30.2% Brahman for Brangus, and 63.9-65.3% Shorthorn and 34.7-36.1% Brahman in Santa Gertrudis. The estimated GBC of ancestries for Santa Gertrudis roughly agreed with the pedigree-expected values. However, the estimated GBC in Brangus showed a considerably larger Angus composition than the pedigree-expected value (62.5%). The elevated Angus composition in the Brangus could be due to the mixture of some 1/2 Ultrablack animals (Brangus×Angus). Another reason could be the consequences of selection in Brangus cattle for phenotypes where the Angus breed has advantages.

Environmental effects on pre-weaning traits in Santa Gertrudis cattle

We aimed to evaluate environmental effects on pre-weaning traits of Santa Gertrudis cattle. We used 213 standardized records for adjusted 205-day weight at weaning (W205), average daily gain from birth to weaning (AGD), and number of days to gain 160 kg from birth to weaning (D160), obtained from the Santa Gertrudis Breeders' Association for animals born between 1990 and 1997. The files were edited with information regarding cow age at calving (CAC) and contemporary group (CG), for which the effects of year and season of birth, animal category, herd, and sex were considered. It was observed that cow age at calving, which had linear and quadratic effects, and effect of contemporary group were significant (P &lt; 0.0001) for the evaluated traits. Estimated averages were 198.05 ± 40.64 kg, 0.790 ± 0.198 kg day-1, and 288.05 ± 67.18 days for W205, ADG, and D160, respectively. Males were 4.67 kg heavier (197.17 kg) than females, on average. Regarding the animal category effect, the classified females were 2.3% heavier than the unclassified, on average. On average, animals born in the dry season were 1.6% lighter than those born in the rainy season (197.18 kg). Thus, environmental effects are important and should be considered in any analysis model.

Comparing SNP panels and statistical methods for estimating genomic breed composition of individual animals in ten cattle breeds

BackgroundSNPs are informative to estimate genomic breed composition (GBC) of individual animals, but selected SNPs for this purpose were not made available in the commercial bovine SNP chips prior to the present study. The primary objective of the present study was to select five common SNP panels for estimating GBC of individual animals initially involving 10 cattle breeds (two dairy breeds and eight beef breeds). The performance of the five common SNP panels was evaluated based on admixture model and linear regression model, respectively. Finally, the downstream implication of GBC on genomic prediction accuracies was investigated and discussed in a Santa Gertrudis cattle population.ResultsThere were 15,708 common SNPs across five currently-available commercial bovine SNP chips. From this set, four subsets (1,000, 3,000, 5,000, and 10,000 SNPs) were selected by maximizing average Euclidean distance (AED) of SNP allelic frequencies among the ten cattle breeds. For 198 animals presented as Akaushi, estimated GBC of the Akaushi breed (GBCA) based on the admixture model agreed very well among the five SNP panels, identifying 166 animals with GBCA = 1. Using the same SNP panels, the linear regression approach reported fewer animals with GBCA = 1. Nevertheless, estimated GBCA using both models were highly correlated (r = 0.953 to 0.992). In the genomic prediction of a Santa Gertrudis population (and crosses), the results showed that the predictability of molecular breeding values using SNP effects obtained from 1,225 animals with no less than 0.90 GBC of Santa Gertrudis (GBCSG) decreased on crossbred animals with lower GBCSG.ConclusionsOf the two statistical models used to compute GBC, the admixture model gave more consistent results among the five selected SNP panels than the linear regression model. The availability of these common SNP panels facilitates identification and estimation of breed compositions using currently-available bovine SNP chips. In view of utility, the 1 K panel is the most cost effective and it is convenient to be included as add-on content in future development of bovine SNP chips, whereas the 10 K and 16 K SNP panels can be more resourceful if used independently for imputation to intermediate or high-density genotypes.

The influence of animal traits on feedlot profitability of Santa Gertrudis cattle in South Africa

ABSTRACTApproximately 75 per cent of South Africa’s beef is finished by feedlots. The profitability of the beef industry remains under pressure due to various external factors. Previous research has shown that many factors influence feedlot performance and profitability. It is, however, very difficult to judge an animal’s inherit feedlot performance before it enters the feedlot. The aim of this study was to explore the relationship between the animal traits of Santa Gertrudis bulls and the feedlot profitability of these bulls. Analysed traits included the sheath score, capacity score and build score as high scores for these traits are believed to be associated with better feedlot performance. The data for this study was collected from 48 Santa Gertrudis bull calves. The profitability of feeding cattle was expressed as the Total Margin (TM) and Feed Margin (FM). Given the nature of the dependant variables, Ordinary Least Squared regressions were used for the analyses with TM and FM as dependent variables. Results show that although both models were significant, the sheath score was the only individual trait that proved to be significantly correlated with both TM and FM. Sheath score proved to be negatively correlated with TM and FM while it was expected, through popular belief, to be positively correlated. This implies that animals with lower sheath scores, thus with sheaths closer to their bodies, perform better in the feedlot and may affect the TM and FM positively. The magnitude of this trait still remains under question and further research is required.

Local immune response to larvae of Rhipicephalus microplus in Santa Gertrudis cattle.

This study investigated the local immune response at larval attachment sites in Santa Gertrudis cattle with low and high levels of tick resistance. Skin samples with tick larvae attached were collected from Santa Gertrudis cattle at the end of a period of 25 weekly infestations, when the animals manifested highly divergent tick-resistant phenotypes. There was a tendency for more CD3+ , CD4+ , CD8+ , CD25+ , γδ T cells and neutrophils to concentrate at larval tick attachment site in susceptible cattle than in resistant cattle but the differences were significant only for γδ T cells and CD4+ cells. Most of the cattle developed intra-epidermal vesicles at the larval attachment site but the predominant cell within or around the vesicles was the neutrophil in susceptible animals and eosinophil in the resistant animals. The monoclonal antibodies (mAbs) specific for CD45 and CD45 RO antigens reacted with skin leucocytes from a higher number of susceptible cattle than resistant cattle. Our data suggest that some of the cellular responses mounted at larval attachment site are not involved in tick protection. The mAbs specific for CD45 and CD45 RO directly, or a test for CD45 genotype might be developed as markers of tick susceptibility or resistance.

Peripheral cellular and humoral responses to infestation with the cattle tick Rhipicephalus microplus in Santa Gertrudis cattle.

Resistance to cattle tick infestation in single-host ticks is primarily manifested against the larval stage and results in the immature tick failing to attach successfully and obtain a meal. This study was conducted to identify immune responses that characterize the tick-resistant phenotype in cattle. Thirty-five tick-naïve Santa Gertrudis heifers were used in this study, thirty of which were artificially infested for thirteen weeks with tick larvae while five animals remained at a tick-free quarantine property to serve as a control group. Following thirteen weeks of tick infestation, the animals in this trial exhibited highly divergent tick-resistant phenotypes. Blood samples collected throughout the trial were used to measure peripheral immune parameters: haematology, the percentage of cellular subsets comprising the peripheral blood mononuclear cell (PBMC) population, tick-specific IgG1 and IgG2 antibody titres, IgG1 avidity for tick antigens and the ability of PBMC to recognize and proliferate in response to stimulation with tick antigens in vitro. The tick-susceptible cattle developed significantly higher tick-specific IgG1 antibody titres compared to the tick-resistant animals. These results suggest that the heightened antibody response either does not play a role in resistance or might contribute to increased susceptibility to infestation.

Immuno-fluorescence staining patterns of leukocyte subsets in the skin of taurine and indicine cattle

The immuno-staining patterns of skin leukocytes were investigated in three breeds of cattle: Holstein–Friesian, Brahman and Santa Gertrudis of similar age before and after tick infestation. The antibodies specific for CD45 and CD45RO reacted with cells in the skin of all Holstein–Friesian cattle but did not react with cells in the skin of any Brahman cattle. The same antibodies reacted with cells from the skin of four (CD45) and seven (CD45RO) of twelve Santa Gertrudis cattle. The antibodies specific for T cells and γδ subset of T cells recognized cells from all three breeds of cattle. The antibody specific for MHC class II molecules labelled cells of mostly irregular shape, presumably dermal dendritic cells and/or macrophages and Langerhans cells. The antibody specific for granulocytes (mAb CH138) reacted with cells only in sections cut from skin with lesions. The antibody specific for CD25+ cells labelled regularly shaped cells that showed a wide range of intensities of staining.

Intervention of Genetic Flow of the Foreign Cattle toward Diversity of Phenotype Expressions of Local Cattle in the District of Banyuwangi

The aims of the present research are two folds: to know the phenotypic diversity and to reconstruct the cross-breeding pattern of local cattle in Banyuwangi. Based on three sampling areas, it was found that there were 32 phenotypic cattle (10 in the sub districts of Rogojampi, 16 in Tegaldlimo and 6 in Glagah areas). The phenotypic varieties were caused by two factors, namely the flow of genetic intervention of the other local cattle (Bali, Ongole, and Brahman cattle) and the artificial insemination program using the semen of Limousine, Simmental, Aberdeen Angus and Santa Gertrudis cattle. © 2010 Biodiversitas, Journal of Biological DiversityKey words: flow of genetic intervention, local cattle, phenotypic variation

Bovine Abortions Associated with Bacteroides Fragilis Fetal Infection

Two Santa Gertrudis cattle from a herd of 105 aborted within a 24-hour period. Bacteroides fragilis was isolated from tissues of each aborted fetus. Histopathologic lesions included placentitis and bronchopneumonia in which gram-negative, rod-shaped organisms were visible. The diagnostic workup failed to reveal other causes of abortion. Anaerobes are rarely implicated in bovine abortions, and no other report was found that described abortion in cattle due to B. fragilis.

Carcass quality traits among crosses of angus, Santa Gertrudis and Gelbvieh beef cattle

Carcass quality traits among crosses of angus, Santa Gertrudis and Gelbvieh beef cattle

Carcass quality traits in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

Carcass quality traits in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

Growth characteristics in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle.

A total of 343 calves (males and females) were evaluated for preweaning average daily gain, weaning weight (WW), feedlot average daily gain to slaughter (ADGF), slaughter weight (SW), pelvic height (PH), pelvic width, pelvic area, weaning conformation score (WS) and ratio of weaning weight to the dam's weight at weaning (R). Mating types included straight-bred Angus (A) and Santa Gertrudis (S), the reciprocal crosses of these two breeds and Gelbvieh (G) X Angus. Straightbred S and A X S crosses had the heaviest WW, followed by S X A and G X A crosses; straightbred A had significantly smaller WW than all other mating types. The crossbreds and the straightbred S had higher WS than straightbred A. The ratio of WW to cow weight was largest for S X A. The straightbred S and A X S crosses had significantly lower R values than the other mating types. Weaning weight per cow exposed, computed as the product of weaning rate and weight, indicated that straightbred A had an advantage over the other mating types (156.5 kg), whereas S and S X A were intermediate (147.9 and 147.6 kg, respectively) and A X S was lowest (128.9 kg). Feedlot gain was highest for A X S, though not significantly greater than for straightbred S or G X A. Straightbred A gained significantly less than other mating types except S X A. Straightbred A were found to be significantly smaller at slaughter than the other mating types. The S X A and G X A were intermediate; the straightbred S and A X S were significantly larger for SW.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of the productivity of Prosopis tamarugo on livestock production in the Pampa del Tamarugal — a review

This paper reviews the uses of the nitrogen-fixing trees Prosopis tamarugo (tamarugo) and P. chilensis (algarrobo) in the deserts of northern Chile where the rainfall is less than 1 mm yr −1. These forests consist of 3200 ha of natural stands and 22,980 ha of plantations. The primary use of these trees has been to support goat and sheep production through grazing of the leaves and pods. The water for these trees comes from an underground water table whose level does not fall and that appears to be fed from an aquifer whose origin must be of higher elevation in the Andes. The water table generally ranges from 3 to 10 m in depth and the underground salinity is about 1500 mg 1 −1 of total dissolved solids. The height growth of the trees is significantly greater where the water table is less than 4 m below the surface. The fruit and foliage of small, medium, and large tamarugo trees and medium and large algarrobo trees were collected to determine forage yield per tree and to develop regression equations relating total pod production per tree and forage collections from smaller litter collection boxes. The mean algarrobo production (largest trees) was 31 kg per tree in 1981 and 117 kg per tree in 1982. The mean tamarugo forage production was 87 kg per tree in 1981 and 104 kg per tree in 1982. Great variation in production per tree and production between years was observed and this greatly complicates management of the trees for forage production. The digestible protein of the leaves and fruits of both species was too low to support growth and reproduction of the animals without supplementation. Management of 5000 sheep of the breeds Precoz Merino, Australian Merino, and Karakul showed that Karakul sheep were best adapted to these desert conditions. Hereford, Galloway, and Santa Gertrudis cattle were also examined. Angora goats were examined for use in the Pampa for mohair production but their long hair became a problem with the thorny trees and this breed was eliminated in favor of the meat breeds Criollo and Pampinos. A supplement feed consisting of 25% alfalfa hay, 45% wheat bran, and 30% sheep feces was used for cattle. Feces were not used in the supplement for sheep and goats. An excellent reproduction rate was obtained (90% of the cattle, sheep and goats produced an average of 1 offspring per animal bred) when a management system was used that included vitamin A,D, and E supplementation, pregnancy determination, and supplemental feed for pregnant animals.

Reproductive performance in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle.

Angus (A), Santa Gertrudis (S), and Gelbvieh (G) sires were mated to A and S dams to produce five mating types (A X A, S X S, S X A, A X S and G X A) in each of four calf crops. The study involved 501 matings. Overall means for the traits measured (calves born/cows exposed, Julian birthdate, calving ease, percentage of live calves at 24 h, birth weight, survival to weaning and gestation length) were 74.2%, 48.8 d, 96.4%, 33.2 kg, 95.4% and 283.8 d, respectively. Angus dams had a 14 percentage point (P less than .05) advantage over S dams for percentage of calves born/cows exposed. The effect of heterosis in crosses of A and S for percentage of calves born/cows exposed was negative (-11.1%) and approached significance. The percentage of calves born/cows exposed were 84.4, 70.4, 76.1 and 62.3 for the A X A, S X S, S X A and A X S mating types, respectively. Matings involving A sires and dams produced calves significantly earlier in the calving season than did matings involving S sires and dams. Matings involving S sires and dams produced calves with significantly longer gestation periods than matings of A sires and dams. Calving ease score and survival to weaning were not affected by breed of sire, breed of dam, age of dam, sex of calf, or the interaction of breed of sire X breed of dam. Percentage of live calves at 24 h indicated that straightbred S calves were significantly less viable at birth than the other four mating types.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison between cervical dimensions of pregnant and nonpregnant Santa Gertrudis and [formula omitted][formula omitted] cows

Cervical measurements were recorded on palpation per rectum for 603 Bos taurus , Santa Gertrudis, and crossbred cattle. Postmortem cervical measurements were recorded for 77 of these cows. Antemortem measurements were positively correlated with those taken at postmortem examination (cervical diameter: r=0.75, P<0.01 and cervical length: r=0.29, P<0.06). Cervical diameters from antemortem and postmortem specimens were greater in Santa Gertrudis cattle than in Bos taurus and crossbred cattle (P<0.05). Cervical shape was different between Santa Gertrudis cattle and Bos taurus or crossbred cattle (P<0.01), with Santa Gertrudis cows having a higher incidence of conical shaped cervices than other breeds. Within Santa Gertrudis cattle, the incidence of conical cervical shape increased with age (P<0.05). Conical cervical shape was associated with a lower pregnancy rate in all breeds (P<0.01). Within Santa Gertrudis cattle, conical cervical shape was associated with a lower pregnancy rate in 1- to 4-year-old cows (P<0.05) but not in cows more than 4 years of age (P>0.05).

Effects of various proportions of wheat, bran or pollard in sorghum grain fattening diets on liveweight gain, feed efficiency and carcase composition of Hereford and Hereford × Santa Gertrudis cattle

A 3 x 2 x 2 factorial design was used to examine the wheat by-products pollard and bran as a replacement in all-sorghum grain feedlot diets. The by-products replaced either 10, 30 or 50 per cent of the sorghum. Fourteen groups each of five Hereford steers of a mean initial shrunk liveweight of 251.5 � S.E. 0.16 kg and seven groups each of five Santa Gertrudis x Hereford cross bullocks of 391.7 � 0.16 kg were used. They were slaughtered at a mean final shrunk liveweight of 407.0 � 3.54 and 534.5 � 5.04 kg respectively. Production results from cattle receiving 50 per cent by-products were significantly inferior to lower levels of by-product. There were no significant differences between 10 and 30 per cent by-product. Cattle receiving pollard performed significantly better than those receiving bran. The growth rate of the Hereford steers of 1.24 kg day-1 was inferior (P &lt; 0.01 ) to that of 1.41 for the Santa Gertrudis x Hereford bullocks, but the estimated gain in carcase weight of 0.75 kg day-1 was the same. The feed conversion ratio per unit of carcase weight gain favoured the Hereford steers (9.91 vs. 11.95; P &lt; 0.01), but the feed conversion ratio per unit of liveweight gain was not significantly different (6.29 vs. 6.06). The total body fat figures were comparable for steers and bullocks -(mean 20.4 per cent). Both the percentage total yield of saleable meat and the percentage yield from the hindquarter were significantly greater (P &lt; 0.01) in the Santa Gertrudis x Hereford cross bullocks (71.4 vs. 69.5 and 36.8 vs. 35.5 respectively).

The performance of Santa Gertrudis, Sahiwal, Brahman and cross-bred animals in the intermediate savannahs of Guyana: 2. Birth weight and preweaning performance

SUMMARYData collected over a period of 11 years at the Ebini Livestock Station in the intermediate savannahs of Guyana were analysed to determine the effect of breed or cross, sire, sex, year and season of birth of calf, and age and length of calving interval of the dam on weights at birth and at 4, 8 and 12 months of age, in Santa Gertrudis, Sahiwal and Brahman cattle. The heritability of body weights at the different ages was estimated.

Comparative reproductive performance of Brahman and Santa Gertrudis cattle in a hot humid environment 2. Factors affecting calving interval

SUMMARYOver a 15-year period 1011 calving intervals from 187 Brahman (B) cows and 687 calving intervals from 146 Santa Gertrudis (SG) were examined. Year of calving significantly affected intervals in both breeds. Season of calving and parity of dam were both important in SG. Longer intervals were seen in B than SG (437 v. 406 days). Repeatability of calving interval was low (&lt; 0·02). The average life-time calving interval was significantly related to total calf production in that cows with shorter mean intervals had more calves in their lifetime.