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PubMed2006

Local inflammation as a possible mechanism of resistance to gastrointestinal nematodes in Angus heifers.

Understanding mechanisms of resistance to gastrointestinal nematodes is important in developing effective and sustainable control programs. A resource population of Angus cattle consisting of approximately 600 animals with complete pedigree records has been developed. The majority of these animals were completely characterized for their resistance to natural challenge by gastrointestinal nematodes. As the first step towards understanding the molecular basis of disease resistance, we investigated expression profiles of 17 cytokines, cytokine receptors, and chemokines using real-time RT-PCR in animals demonstrating resistance or susceptibility to pasture challenge. The animals exposed to natural infection for approximately 6 months were treated to remove existing parasites and then experimentally challenged with both Ostertagia ostertagi and Cooperia oncophora. The mRNA expression profiles of these genes in abomasal and mesenteric lymph nodes (ALN, MLN), fundic and pyloric abomasa (FA, PA), and small intestine (SI) were compared between resistant and susceptible animals. Resistant heifers exhibited elevated expression of inflammatory cytokines such as TNFalpha, IL-1beta, and MIP-1alpha in fundic and pyloric abomasa 7 days post infection. Expression levels of IL-10, polymeric immunoglobullin receptor gene (PIGR), and WSX-1 were also 2.7-19.9-folds higher in resistant than susceptible heifers in these tissues. No difference in expression of CXCL6, CXCL10, IFN-gamma, IL-2, IL-4, IL-6, IL-8, IL-12 p40, IL-13, IL-15 and IL-18 was observed between the two groups. The expression of MIP-1alpha, IL-6, and IL-10 was also elevated in small intestines in resistant animals. In contrast, little difference in expression of these genes was detected between resistant and susceptible groups in the draining lymph nodes. These data indicate that resistant animals can better maintain inflammatory responses at the site of infection, suggesting a possible novel mechanism of resistance.

Animals↗

PubMed2001

Genomic tools to improve parasite resistance.

The natural genetic variability of the ruminant immune system provides a feasible means to control gastrointestinal (GI) parasite infection without anthelmintics. However, the paradigm of traditional selection has not been effectively applied to the moderately heritable traits of parasite resistance (h approximately equal to 0.3) due to the difficulty and expense of gathering accurate phenotypes in a commercial production setting. These characteristics make host traits related to GI nematode infection ideal candidates for genomics-based research. To initiate explanation of important allelic differences, economic trait loci (ETL) are being identified and mapped using a resource population of Angus cattle segregating for GI nematode resistance and susceptibility to the two most common nematode parasites of US cattle, Ostertagia ostertagi and Cooperia oncophora. The population is composed of five generations of half-sib progeny with complete phenotypic records produced from controlled infections. To detect the genomic locations of the three distinct phenotypic traits being expressed (innately immune, acquired immune, and immunologically non-responsive), genotypes have been generated for DNA markers (N=199) spaced at regular intervals (approximately 20cm intervals) throughout the entire genome (3000cm). Although initial ETL detection may be limited by half-sib family size, the unique structure of this population provides additional statistical power for refining map position of potential ETL. After allele frequency and contribution to phenotype are determined in this population, marker tests associated with ETL most beneficial for controlling parasite infection can be accurately used for selection. Comparative map and functional genomic information from humans and other species of biomedical importance will be utilized in further investigations to elucidate the genes underlying ETL.

Animals↗

PubMed1998

Starvation depresses acylglycerol biosynthesis in bovine subcutaneous but not intramuscular adipose tissue homogenates.

The primary objective of this study was to document the effects of starvation on acylglycerol biosynthesis in homogenates of intramuscular and subcutaneous adipose tissues. Adipose tissue samples were obtained from 8th-13th thoracic rib sections from 12 Angus cattle (six steers plus six heifers). Three steers and three heifers were starved for 72 h prior to slaughter while the remainder were slaughtered 4 h after food was withheld. Fat-free 700 x g centrifugal fractions were used to measure the esterification of radiolabeled sn-glycerol 3-phosphate (G-3-P) into acylglycerols at 1.0 mM palmitic or stearic acid, or 0.2 mM oleic, linoleic, or alpha-linolenic acid. There were significant tissue x fatty acid interactions for rates of incorporation into diacylglycerols and triacylglycerols; in subcutaneous, but not intramuscular homogenates, palmitic > stearic = oleic = linoleic = alpha-linolenic acid. Subcutaneous homogenates incorporated a greater percentage of G-3-P into triacylglycerols, and a lesser percentage into phospholipid, than intramuscular homogenates (P < 0.05). In intramuscular homogenates, the primary product of G-3-P esterification to saturated fatty acids was phospholipids. When unsaturated fatty acid served as substrates, triacylglycerols and phospholipids were produced in equal proportions in intramuscular homogenates, and triacylglycerols were the predominant product in subcutaneous homogenates. Intramuscular adipose tissue homogenates exhibited no response to starvation, whereas triacylglycerol and diacylglycerol synthesis was depressed by approximately 50% in subcutaneous adipose tissue homogenates. Similarly, phosphatidic phosphohydrolase activity, initially greater in subcutaneous than in intramuscular adipose tissue, was decreased by approximately 50% by starvation in subcutaneous adipose tissue, but not in intramuscular adipose tissue. We conclude that differences in rates of diacylglycerol and triacylglycerol biosynthesis, and response to starvation, between intramuscular and subcutaneous adipose tissues were due to dissimilarities in the activity of phosphatidic phosphohydrolase.

Adipose Tissue↗

PubMed1997

Purification of bovine lysosomal alpha-mannosidase, characterization of its gene and determination of two mutations that cause alpha-mannosidosis.

Bovine kidney lysosomal alpha-mannosidase was purified to homogeneity and the gene was cloned. The gene was organized in 24 exons that spanned 16 kb and its corresponding cDNA contained an open reading frame of 2997 bp beginning from a putative ATG start codon. The deduced amino acid sequence contained a signal peptide of 50 amino acids adjacent to a protein sequence of 949 amino acids that was cleaved into five peptides in the mature enzyme; starting with the peptide derived from the N-terminal part of this precursor, their molecular masses were 35/38 (peptide a), 11/13 (peptide b), 22 (peptide c), 38 (peptide d) and 13/15 kDa (peptide e). Variation in the degree of N-glycosylation accounts for molecular mass heterogeneities of peptides a, b and e. Peptides a, b and c were disulphide-linked. A T961-->C transition, resulting in Phe321-->Leu substitution, was identified in the cDNA of alpha-mannosidosis-affected Angus cattle. In affected Galloway cattle, a G662-->A transition that causes Arg221-->His substitution was identified. Phe321 and Arg221 are conserved among the alpha-mannosidase class-2 family, indicating that the substitutions resulted from disease-causing mutations in these breeds.

Amino Acid Sequence↗

PubMed1994

Serum growth hormone-binding protein (GHBP) in domestic animals as measured by ELISA.

This research was conducted to develop and characterize a competitive ELISA for bovine serum growth hormone-binding protein (GHBP) using recombinant bovine GHBP and a polyclonal rabbit antiserum. In addition to bovine, however, the assay was found to measure some activity in equine, chicken, porcine, ovine, and human sera. The reference standard curve had an effective range of 3 to 200 ng/mL. Recovery of increasing amounts of GHBP added to ovine serum was 103% but seemed to overestimate the amount of GHBP at low concentrations (intercept = 2.5 ng/mL). Recovery from bovine and porcine serum was near ideal but seems to be overestimated at concentrations higher than 50 ng/microL. Within and between assay coefficients of variation were 12.1 and 18.9%, respectively, for a sheep serum pool. Neither exogenous GH (20 ng/mL) nor prolactin (100 ng/mL) interfered with the measurement of GHBP in serum. The GHBP activity measured in increasing doses of serum from ovine, porcine, and bovine inhibited the assay in a parallel manner. This observation suggests that the GHBP antiserum contains antibodies that are directed toward epitopes of GHBP, which are common among these species. Serum GHBP concentrations were similar among samples from a line of miniature Brahman and normal stature Brahman and Angus cattle. In mature ewes, there were no differences in serum GHBP among three different breed types. An increase (P < .0001) in serum GHBP was observed in pigs between 1 and 6 mo of age but no sex effect was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

Silage or limit-fed grain growing diets for steers: II. Empty body and carcass composition.

The influence of energy source (silage- or grain-based) on empty body and carcass composition and adipocyte cellularity independent of rate of gain was tested. Sixty-four Angus steers were allotted to either a forage (ad libitum) or grain (limit-fed) diet for a growing phase (145 d) followed by 45, 75, or 105 d of ad libitum access to a grain-based diet. Eight steers were slaughtered initially and eight from each treatment were slaughtered at the end of the growing phase, and at each of the termination dates. The silage growing diet consisted (DM basis) of 55% sorghum silage (approximately 24% dry matter), 22% alfalfa hay, 11% ground shelled corn, and 11% soybean meal. The grain-based growing diet was composed of 77% ground shelled corn, 5% soybean meal, 14% cottonseed hulls, 3% molasses, and 1% salt and mineral; it was limit-fed to produce the same rate of gain as the silage diet. No implants or ionophores were used. At the end of the growing phase, the steers fed grain were heavier and had a higher percentage of fat in the empty body (24 vs 19% fat) and the carcass (26 vs 21% fat) than did steers fed forage. Rate of gain during the growth phase was related positively to percentage of carcass fat; when corrected for fill, data for both diets fit one regression line for fat vs rate of gain. When adjusted for gain during the growing phase, fat content was not different in empty body or carcass, but internal fat was higher (P < .10) for steers fed grain. After 45 d on the finishing diet, carcass fat remained low (23%), but after 75 and 105 d, fat content reached 27%. Source of energy did not detectably affect carcass composition independent of rate of gain. Cell size of adipocytes from four adipose depots increased with time on feed but were not affected by diet during the growing phase. Lean Choice beef can be produced in only 45 d in the feedlot with medium-framed Angus cattle.

Adipose Tissue↗

PubMed2000

Additive genetic parameter estimates for heifer pregnancy and subsequent reproduction in Angus females.

A primary objective of this study was to determine whether the binary traits heifer pregnancy (HP) and subsequent rebreeding (SR) were heritable in an experimental population of Angus cattle. A second objective was to determine the nature of the additive genetic relationships among HP, SR, and stayability (S(5/1)) in the same population. Heifer pregnancy was defined as the observation of a heifer conceiving and remaining pregnant to palpation at 120 d, given exposure during the breeding season. Subsequent rebreeding was defined as the observation of a 2-yr-old conceiving and remaining pregnant to palpation at 105 d, given pregnancy as a yearling and exposure during the breeding season. Stayability was defined as the probability of a female having at least five calves, given she becomes a dam as a 2 yr old. Data were analyzed using a maximum a posteriori probit threshold model to predict breeding values on the liability scale and Method R procedures to estimate variance components in the determination of heritability (h2). Additive genetic groups were used in determining the additive genetic relationships among these fertility traits. Additive genetic groups were formed on one trait's breeding values and used in the prediction of another trait's breeding values. Analyses yielded h2 estimates that were out of the parameter space 8.5 and 46.3% for HP and SR, respectively, and 5.9% for the reestimation of S(5/1). The majority of point estimates outside the parameter space for SR converged toward 0, whereas those for HP and S(5/1) primarily converged toward 1. From the subsamples producing h2 estimates within the parameter space, average h2 for HP, SR, and S(5/1) were .21, .19, and .15, with standard deviations of .12, .14, and .08, respectively. The estimates of h2 indicate that HP and S(5/1) were heritable and should respond favorably to selection; however, SR did not appear heritable due to the large number of subsamples producing h2 estimates out of the parameter space. Fixed effect estimates for age of dam were significant for HP. From the analyses using additive genetic groups, the relationship among HP and S(5/1) appeared to be nonlinear. This potential nonlinear relationship seen between HP and S(5/1) indicates that selection for improved female fertility would be most effective by having predictions on both traits.

Animals↗

PubMed1987

Energy value of corn wet milling by-product feeds for finishing ruminants.

Five trials were conducted to evaluate the energy value of corn wet milling by-products in finishing diets. In trials 1 (45 finishing lambs, 34 kg) and 2 (70 digestion wethers, 32 kg), Rambouillet X Suffolk lambs fed corn gained faster (P less than .10), more efficiently (P less than .10) and had higher (P less than .01) digestibilities of neutral and acid detergent fiber (NDF, ADF) and starch than lambs fed dry corn gluten feed (DCGF). Lambs fed wet corn gluten feed (WCGF) consumed less feed (trial 1, P less than .05; trial 2, P less than .01), were more efficient (P less than .01) NDF and ADF digestibilities than lambs fed DCGF. Starch, NDF and ADF digestion were higher (P less than .01) for lambs fed WCGF vs wet corn bran (WCB). Lambs fed WCGF gained faster (P less than .10) and consumed more (trial 1, P = .12; trial 2, P less than .10) feed than lambs fed WCB. Dried corn bran increased (trial 1, P less than .05; trial 2, P less than .01) intake and increased (P less than .01) dry matter digestion (DMD) compared with WCB. In trial 3, rates of in vitro dry matter and NDF disappearance were similar among by-product feeds. In trial 4 (50 individually fed Shorthorn-Hereford-Angus steers, 316 kg), steers fed WCGF tended to consume more (P = .14) feed than steers fed DCGF. Corn gluten feed (CGF) replacing 0 to 46% corn decreased gain (linear, P less than .05) and DMD (linear, P less than .10), while starch digestion was highest for 23% CGF (quadratic, P less than .01). A level X CGF type interaction (P = .15) occurred for efficiency due to the lower gain of steers fed 46% DCGF. The efficiency of CGF utilization was 97% that of corn when WCGF replaced 23 or 46% corn or DCGF replaced 23% corn. Dry CGF replacing 46% corn had 87% the value of corn. In trial 5 (186 Hereford-Angus cattle, 310 kg), DCGF replacing 25 and 50% corn had 97 to 100% the efficiency of corn, while intake and gain were not affected. Dry CGF replacing 25 and 50% corn silage increased (linear, P less than .05) intake 11.3% and gain 13.8%. In ruminants, CGF is highly digestible and feed efficiency is similar to corn when WCGF is fed up to 50% of the grain component or when DCGF is fed up to 25% of the grain component.

Animal Feed↗

PubMed2004

Bovine familial convulsions and ataxia in Saskatchewan and Alberta.

Bovine familial convulsion and ataxia, a heritable disorder, is present in crossbred Aberdeen Angus cattle in western Canada. Though the prevalence appears to be low, this genetic defect might become widespread if not controlled. Characteristic histological lesions were seen in the lingula, uvula, or both, of all affected calves regardless of their age.

Alberta↗

PubMed1979

[Hereditary lysosomal storage diseases (author's transl)].

The literature on hereditary lysosomal storage diseases occurring in man and various domestic animals is reviewed. These forms of disease are usually recessively autosomally heritable and are reflected in partial or total deficiency of a lysosomal enzyme, resulting in accumulation of metabolites. The majority of these lysosomal storage diseases show a predilection for localization in the nervous system. As a rule, the main clinical features are neurological symptoms. The first symptoms are usually observed at an early age and the disease is marked by the fact that it is familial in character. Heterozygotes may be identified by controlled haematological studies in a number of these diseases. In domestic animals, these forms of disease may serve as models for human pathology and some may be of economic importance, such as mannosidosis of Angus cattle in New Zealand and GM1 gangliosidosis of Friesian cattle in Ireland.

Animals↗

PubMed2000

Differences in susceptibility to gastrointestinal nematode infection between Angus and Brangus cattle in south Louisiana.

Breed susceptibility to nematode infection was evaluated in Angus (Bos taurus) and Brangus (B. indicus crossbreed) cattle. A cow-calf herd and a yearling replacement heifer herd were monitored during one grazing season. Calves were born in March and were weaned in October. Individual rectal fecal samples were collected monthly from the two herds and processed for fecal egg counts (FEC) and coprocultures. Cow and calf FEC increased from April, reaching maximum values during the summer. Angus cows and calves had significantly (p<0.05) greater FEC than Brangus cows and calves, and Haemonchus and Cooperia were the predominant genera. Replacement heifer FEC showed a similar pattern with maximum levels during late summer/fall, and Haemonchus was the predominant genus. No significant differences were seen between breeds, however, infection levels were consistently lower in Brangus heifers. Ostertagia was present in cows and heifers only in fall/winter, which is consistent with summer inhibition. The data suggested that cows were an important source of pasture contamination for their susceptible calves and that the Brangus breed was relatively more resistant to infection. The use of B. indicus crossbreeds may help in alleviating reliance on chemical control by reducing the rate of pasture contamination and subsequent infection losses.

Animals↗

PubMed2000

Genetic analyses of live-animal ultrasound and abattoir carcass traits in Australian Angus and Hereford cattle.

In order to estimate genetic parameters, abattoir carcass data on 1,713 Angus and 1,007 Hereford steers and heifers were combined with yearling live-animal ultrasound measurements on 8,196 Angus and 3,405 Hereford individuals from seedstock herds. Abattoir measures included carcass weight (CWT), percentage of retail beefyield (RBY), near-infrared measured intramuscular fat percentage (CIMF), preslaughter scanned eye muscle area (CEMA), and subcutaneous fat depth at the 12th rib (CRIB) and at the P8 site (CP8). Ultrasound scans on yearling animals included 12th-rib fat depth (SRIB), rump fat depth at the P8 site (SP8), eye muscle area (SEMA), and percentage of intramuscular fat (SIMF). Records on CWT were adjusted to 650-d slaughter age, and the remaining abattoir traits were adjusted to 300-kg CWT. Scan data were analyzed treating records on males and females as different traits. Multivariate analyses were performed on a variety of trait combinations using animal model and REML algorithm. Heritability (h2) estimates for CWT, RBY, CIMF, CP8, CRIB, and CEMA were .31, .68, .43, .44, .28, and .26, respectively, for Angus and .54, .36, .36, .08, .27, .38, respectively, for Hereford. Pooled across sexes, h2 estimates for SIMF, SP8, SRIB, and SEMA were .33, .55, .51, and .42, respectively, for Angus and .20, .31, .18, and .38, respectively, for Hereford. Genetic correlations (r(g)) between the same pair of carcass traits measured at yearling through scanning and directly at the abattoir were moderate to strongly positive, suggesting that selection using yearling ultrasound measurements of seedstock cattle should result in predictable genetic improvement for abattoir carcass characteristics. Estimates of r(g) between the scanned fat measurements and RBY were negative, ranging from -.85 for Angus heifers to -.05 for Hereford heifers. Also, the estimates of r(g) between SEMA and the fat records measured at the abattoir were negative and ranged from -.94 in Hereford heifers to -.02 in Angus heifers.

Adipose Tissue↗

PubMed1985

Heterosis retained in advanced generations of crosses among Angus and Hereford cattle.

Data from 1,909 purebred, F1, backcross and F2 and F3 inter se combinations of Angus and Hereford were used to estimate average individual, maternal and grandmaternal genetic effects, individual and maternal heterosis, dominance and epistatic genetic effects. Models for evaluating heterosis and epistatic or recombination effects were discussed. Average individual effects indicate that Angus, compared with Hereford, had calves that were born earlier, had lighter birth weights, lower pre- and postweaning gains and lower pregnancy rates. Angus also produced lighter weight carcasses with more fat cover and marbling. Maternal effects of Angus were in the direction of reduced birth weight, greater calving ease, higher preweaning but lower postweaning growth rate and increased fatness when contrasted with Hereford. There was a tendency for opposite direction of maternal and grandmaternal effects for traits influenced by preweaning maternal environment. When additive X additive effects were ignored, total heterosis was significant for earlier day born, heavier birth weight, preweaning and postweaning gain, and heavier and fatter carcasses. Heterosis retained in F3 inter se vs F1 generation crosses indicated that net epistatic effects were relatively negligible for date of calving, birth weight, weaning gain and fat cover. There was a greater reduction of heterosis effects than expected from dominance alone for survival, pregnancy and marbling score. Loss of heterosis in F3 was less than expected for postweaning gain, carcass weight and rib eye area. Except for survival, pregnancy and marbling, these deviations from dominance expectations, or lack of them, are favorable for F3 composite populations.

Animals↗

PubMed1996

Heat tolerance in two tropically adapted Bos taurus breeds, Senepol and Romosinuano, compared with Brahman, Angus, and Hereford cattle in Florida.

Two trials were conducted with heifers to determine heat tolerance among temperate Bos taurus (Angus, Hereford), Bos indicus (Brahman), tropical Bos taurus (Senepol, Romosinuano), and the reciprocal crosses of Hereford and Senepol. Differences among breeds in temperament score, circulating concentrations of cortisol, and blood packed cell volume were also investigated. Trial 1 used 43 Angus, 28 Brahman, 12 Hereford, 23 Romosinuano, 16 Senepol, 5 Hereford x Senepol (H x S), and 5 Senepol x Hereford (S x H) heifers. Trial 2 used 36 Angus, 31 Brahman, 9 Hereford, 14 Senepol, 19 H x S, and 10 S x H heifers. On the hottest summer date in Trial 1, rectal temperature of Angus was greater (P < .001) than that of Brahman, Senepol, or Romosinuano. Rectal temperature and plasma cortisol were significantly less in Senepol than in Brahman, suggesting that the differences in rectal temperature between these breeds may be due to differences in stress response possibly related to differences in temperament. Reciprocal crosses of Hereford and Senepol had rectal temperatures nearly as low as that of Senepol and displayed substantial heterosis (-9.4%, P < .05) in log10 rectal temperature on the hottest summer date. On both the hottest and coolest dates in Trial 1, Angus heifers had significantly faster respiration rates than Brahman, Romosinuano, or Senepol heifers, and Brahman had significantly slower respiration rates than Romosinuano or Senepol. On the hottest summer date in Trial 2, rectal temperature in Angus heifers was greater (P < .001) than in Brahman or Senepol had rectal temperatures similar to that of Senepol, or heterosis for log10 rectal temperature was similar to that in Trial 1 (-9.8%, P < .05). Considering rank order among breeds, Brahman always had the slowest respiration rate and greatest packed cell volume. Brahman had significantly greater temperament scores and plasma cortisol concentrations than Angus or Senepol, except that plasma cortisol was not different between Brahman and Senepol on the hottest summer date. On this date, rectal temperature did not differ between Brahman and Senepol, which supports the hypothesis that there is a relationship between response to stress and rectal temperature that helps explain differences in rectal temperature between Brahman and Senepol. The results of these trials demonstrate heat tolerance of the Senepol and Romosinuano, two Bos taurus breeds. Furthermore, the results suggest a substantial level of dominance of the Senepol's ability to maintain constant body temperature in a hot environment as measured by rectal temperature in crosses with a non-adapted breed.

Adaptation, Physiological↗

PubMed1995

Differences in copper status and copper metabolism among Angus, Simmental, and Charolais cattle.

Thirty-eight pregnant Angus, Charolais, and Simmental heifers and their offspring were used to determine whether differences in Cu metabolism existed among breeds. The heifers were fed either 0 or 10 mg of supplemental Cu per kilogram of DM. Calves were born between d 70 and 125 of the 280 d experiment. There were few differences among breeds in plasma Cu concentration and ceruloplasmin activity when heifers were fed supplemental Cu. When heifers were not fed supplemental Cu, Angus heifers had greater (P < .10) plasma Cu concentrations than Simmental heifers from d 0 until 140 and Charolais heifers from d 28 until 140. Angus heifers had greater (P < .10) ceruloplasmin activity than Charolais and Simmental heifers between d 28 and 196. When dams were fed supplemental Cu, Angus calves had greater (P < .10) plasma Cu concentrations than Simmental calves on all days tested and Charolais calves on d 252 and 280. Ceruloplasmin activity of Angus calves in the Cu-supplemented group was greater (P < .10) than that of Charolais calves on d 224 and 280 and Simmental calves from d 224 until 280. Angus calves born to dams not receiving supplemental Cu had greater (P < .10) plasma Cu concentrations and ceruloplasmin activities than Simmental calves on all days tested. Angus calves also had greater (P < .10) plasma Cu concentrations than Charolais calves on d 196 and greater ceruloplasmin activities than Charolais calves from d 168 until 224. Eight Angus and eight Simmental steers were used to evaluate apparent Cu absorption and retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Performance of Hereford and two-breed rotational crosses of Hereford with Angus and Simmental cattle: II. Carcass traits of steers.

Calf carcass traits were evaluated for Simmental (S) x Hereford (H) and Angus (A) x H crosses in two-breed rotations and for straightbred H. Data were grouped into seven dam breed categories: straightbred Hereford (H), F1 S x H cows (SH), S x H cows of low percentage H (SHS), S x H cows of high percentage H (HSH), F1 A x H cows (AH), A x H cows of low percentage H (AHA) and A x H cows of high percentage H (HAH). Straightbred H and crossbred SH, AH, SHS and AHA cows were mated to H bulls, HSH cows were mated to S bulls and HAH cows were mated to A bulls. Calves from the S x H rotation produced heavier carcasses with less fat, lower quality grade, larger longissimus area and increased estimated cutability compared to A x H calves. Some significant intergenerational differences were observed within rotations, particularly within S x H. Calves from HSH cows mated to S bulls produced carcasses with less fat cover, lower quality grade, larger longissimus muscle area and higher estimated cutability compared to calves from SHS dams mated to H bulls. Within both rotations, evaluation of carcass weight per day of age indicated that postweaning ADG was lower for generations for which H was the sire breed. Carcass traits of calves from SHS, HSH, AHA and HAH dam breed groups from the last 3 yr of the study when calves were fed under two different postweaning management systems were evaluated in a separate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2000

Relationship between a bull's parental genetic merit difference and subsequent progeny trait variability in Angus, Gelbvieh, and Limousin cattle.

Data from the American Angus Association, American Gelbvieh Association, and the North American Limousin Foundation were analyzed to determine whether parental genetic differences are associated with Mendelian sampling of their bull progeny or with Mendelian sampling variances and weight variances of their bull progeny's offspring. Parental differences were measured as the difference between the parents' EPD for birth weight (DIF(BW)), weaning weight direct (DIF(WW)), and yearling weight (DIF(YW)). A bull's data were used if both parents had calculated EPD and the bull had at least 25 progeny with records for the specific trait. Traits calculated for each bull were his Mendelian sampling (MS(Bull)), progeny Mendelian sampling variance (MSsigma2progeny), progeny weight variance (WTsigma2), and progeny corrected weight variance (CWTsigma2 = adjusted weight minus appropriate dam EPD) for birth, weaning, and yearling weights. Pearson correlations were computed between DIF(BW), DIF(WW), and DIF(YW) and MS(Bull), MSsigma2progeny, WTsigma2, and CWTsigma2 for each trait, within each breed. Across breeds, the correlations ranged from -.07 to .11 for MS(Bull) .01 to .14 for MSsigma2progeny, -.06 to .09 for WTsigma2, and -.06 to .08 for CWTsigma2. Although some of the correlations were significantly different from zero their relatively small magnitude indicates little relationship between parental differences in genetic merit and subsequent offspring variability for each of the three breeds.

Animals↗

PubMed1984

Performance of crosses among Hereford, Angus and Simmental cattle with different levels of Simmental breeding. II. Effect of calf breed on cow productivity.

Hereford cows were randomly bred to Hereford, Angus, Simmental X Hereford and Simmental sires. Each sire breed group was represented by nine or 10 sires. These matings produced approximately 100 calves in each sire breed group over 4 yr. The objective of this study was to determine the effect of calf breed on characteristics of the cow such as milk production, reproduction, measures of condition, weight and changes in condition and weight during lactation. All of the cows were contemporary Herefords that were raised and managed under similar environmental conditions. Hence, any detection of an important effect of calf breed on cow productivity should be a reflection of different levels of maternal requirement imposed on the cow by the different calf breed groups. Cows that raised crossbred calves gained less weight from precalving to weaning, had lower condition scores at weaning, had smaller gains in weight change per unit of height and experienced a lower pregnancy rate. All results consistently showed that crossbred calves challenged the maternal ability of their dams to a greater degree than the straightbred calves and that among the crossbred calves, those by Simmental sires challenged their dams the most. It appeared that calf breed group effects on cow traits were at least partially mediated through calf growth rate, but not through parturition stress. Therefore, benefits realized from crossbreeding need to be weighted against possible unfavorable results.

Animals↗