Effect of dam and sire qualitative hip conformation scores on progeny hip conformation.

OBJECTIVE: To determine in dogs what effect using hip conformation scores assigned by the Orthopedic Foundation for Animals (OFA) as a criterion for breeding selections would have on hip conformation scores of the progeny. DESIGN: Longitudinal study. ANIMALS: English Setters, Portuguese Water Dogs, Chinese Shar-peis, and Bernese Mountain Dogs for which OFA hip conformation scores were known. PROCEDURE: Pedigree data were obtained from the national breed clubs and the American Kennel Club and merged with data from the OFA hip conformation score database. An ANOVA was used to evaluate the effects of sex, age at the time of radiographic evaluation, and year of birth on the variation in hip conformation scores among the progeny. Heritability was estimated by use of within-year midparent offspring regression analyses. RESULTS: Significant differences in progeny hip conformation scores between sexes were not detected, but age at the time of radiographic evaluation and year of birth had a significant effect on hip joint conformation of the progeny. Estimated heritability (mean +/- SE) was 0.26 +/- 0.03, and dam and sire hip conformation scores had a significant effect on progeny hip conformation scores. Annual decreases in percentage of dysplastic progeny and increases in percentages of progeny and breeding dogs with phenotypically normal hip joint conformation were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that hip conformation scores have moderate heritability in dogs and selection of breeding stock with better hip conformation scores will increase the percentage of progeny with phenotypically normal hip joint conformation.

Two-way selection for daily gain and feed conversion in a composite rabbit population.

We conducted a two-way selection experiment in a composite rabbit population to investigate the responses to selection for postweaning ADG and feed conversion (FC). Two generations of crossing, followed by four generations of random pair matings, preceded three generations of selection. Selection was practiced within four lines: high-feed conversion (HFC), low-feed conversion (LFC), high gain (HG), and low gain (LG). Data on 1,446 rabbits from the random mating and selection generations were fitted to an animal model to estimate heritabilities of and the genetic correlation between ADG and FC. The two-trait model included rabbit and common litter random effects and line, generation, and sex fixed effects. Estimates of heritability of ADG and FC were .48 and .29, respectively, and the genetic correlation between them was -.82. Common litter environmental effects accounted for a proportion of .11 and .13 of the phenotypic variation of the two traits, respectively. For ADG (in g/d) the regressions of mean breeding values on generation number during the selection period were 1.23 +/- .12 (P < .01) in the HG line and -.86 +/- .12 (P < .01) in the LG line; the regressions for FC (in g feed/g gain) were -.07 +/- .01 (P < .01) in the HFC line and .03 +/- .01 (P < .05) in the LFC line. Selection for ADG was effective in improving ADG and FC.

Effects of environmental heat and intake of tall fescue seed infested with Acremonium coenophialum on the acid-base status of young bulls.

Effects of high environmental temperature and dietary intake of tall fescue (Festuca arundinacea) seed containing the endophyte Acremonium coenophialum on bovine acid-base status were studied using 3 groups of bull calves (2 Simmental, 1 Angus). Experimental animals were housed in controlled-climate chambers and subjected to gradual increases in environmental temperature, first while being fed an endophyte-free diet and then while being fed a diet containing 17% endophyte-infested fescue seed. Marked acid-base disturbances were not observed in any animals. In general, Pco2, HCO3-, base excess, and arterial blood pH values were reduced in response to heat stress, both with endophyte-free and endophyte-containing diets. In most individuals anion gap increased. These results reflected metabolic compensation for mild chronic alveolar hyperventilation and retention of organic acids. These findings suggest that, under conditions similar to those found during the summer in central Missouri, normal cattle should not be at great risk of developing respiratory alkalosis or other severe acid-base disturbances as a result of heat stress and/or intake of tall fescue endophyte.

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.

Genetic and phenotypic parameter estimates of pelvic measurements and birth weight in beef heifers.

Data on 1210 spring-born (1983 to 1988) yearling heifers were analyzed by paternal half-sib procedures to obtain genetic and phenotypic parameter estimates involving birth weight and pelvic measurements. Data included records on 629 Angus, 325 Simmental, and 256 Salers representing 93, 49, and 22 paternal half-sib sire groups, respectively. Heritabilities for birth weight (BW), pelvic height (PH), pelvic width (PW), and pelvic area (PA) for Angus were 0.30, 0.61, 0.28, and 0.43, respectively. Corresponding values for Simmental and Salers heifers were 0.14, 0.34, 0.44, 0.37, and 0.18, 0.02, 0.29, 0.15, respectively. Genetic correlations among pelvic measurements (PH-PW, PH-PA, PW-PA) were positive (0.25 to 1.03) except for the estimate of -0.07 for PH-PW in Simmentals. Genetic correlations between BW and the 3 pelvic measurements (BW-PH, BW-PW, BW-PA) were negative (-0.18 to -0.36) except for the estimates of 0.53 (BW-PW) and 0.26 (BW-PA) in Simmentals and 2.84 (BW-PH) and 0.39 (BW-PA) in Salers. Phenotypic correlations among pelvic measurements ranged from 0.16 to 0.80. Phenotypic correlations between birth weight and the 3 pelvic measurements were consistently lower (-0.02 to 0.09) than the genetic correlations.

New Zealand white mice: an experimental model of exencephaly.

This is the initial report of an unusually high incidence of exencephaly in inbred New Zealand White (NZW) mice and the congenic NZW-xid strain, in which animals are homozygous for the recessive X-linked immune deficiency (xid) gene. The predominant expression of exencephaly in female pups and a disproportionate decrease in numbers of female pups in litters suggested that exencephaly was part of a continuum of lethal defects expressed preferentially in females. Genetic influence in the expression of exencephaly in NZW mice was postulated because environmental cohort controls did not express this defect. NZW mice are an additional model for studying the pathogenesis of neural tube defects.

Heritability of susceptibility to scrotal herniation in swine.

Data on 5,711 Duroc-sired, 2,227 Landrace-sired, and 2,494 Yorkshire-sired male pigs born over a 9-year period were used to evaluate the genetic influence on scrotal herniation. Differences in frequency of this defect among boar breeds (Duroc, Landrace, and Yorkshire) were significant (P less than 0.01). Differences among sires within the Duroc and Landrace boar groups were significant (P less than 0.001 and P less than 0.05, respectively), but differences within the Yorkshire group were not significant. Frequency of scrotal hernia among male full siblings of affected males was consistently higher than the overall frequency of the defect among progeny in each of their respective breed of boar groups. Percentage of affected pigs among male full siblings of affected males for Duroc, Landrace, and Yorkshire groups, respectively, was 3.0, 3.0, and 2.7 times greater than the overall percentage affected in their respective breed groups. Heritability of susceptibility to scrotal hernia development was estimated to be 0.29 +/- 0.17, 0.34 +/- 0.23, and 0.34 +/- 0.19 in Duroc, Landrace, and Yorkshire-sired pig groups, respectively.

Heritability of liability to cystic ovary development in Holstein cattle.

Data from 249 and 152 records of first and second lactations, respectively, were collected from the files of Dairy Herd Improvement Association and veterinary clinical records of Holstein cows from the J. C. Penny farm of the University of Missouri-Columbia from 1977 through 1987. Incidences of cystic ovaries were .345 and .421 in the first and second lactations, respectively. Heritabilities of liability to cystic ovary development based on correlation of incidences among paternal half-sib relatives were 0.15 +/- 0.44 and 0.11 +/- 0.65 for first and second lactation records, respectively. Corresponding estimates by paternal half-sib analysis of variance, using either original or angle-transformed proportions, were assumed to be zero because sire components of variance were negative. The results suggest that individual selection based on the presence or absence of cystic ovary development would be, at best, very slow in bringing about a reduction in the incidence of this disease in dairy cattle herds.

Decreased fertility in related females heterozygous for the 1/29 chromosome translocation.

Eighteen heifers and 120 cows which were descendants of a presumed 1/29 carrier Simmental bull were karotyped. Nine heifers (50%) and 48 cows (40%) were found to be heterozygous for the 1/29 translocation (59, XX, t(1q;29q)). The other animals were chromosomally normal (i.e., 60, XX) or not karotyped. The 48 1/29 cows were compared with 72 chromosomally normal cows with regards to days to first conception, calving interval, percentage of calves conceived, percentage of calves weaned and production efficiency (% calved conceived x % calved weaned). Nine carrier heifers were compared to the nine noncarrier heifers as to pregnancy status. Carrier, noncarrier and nonkarotyped relatives were compared to each other and to contemporary females with regard to pregnancy status at their initial exposure to males. The percentage of calves conceived (calving efficiency) in the 72 noncarrier and the 48 females heterozygous for the 1/29 translocation were 81.5 and 74.8%, respectively (P<0.07). Although days to first conception was longer and percentage of calves weaned and production efficiency were lower in the female heterozygous for the 1/29 translocation, the differences were not statistically different (P>0.10) from the noncarriers. Pregnancy rate was 44.4 and 66.7% (P>0.10) for nine carrier and nine noncarrier heifers, respectively. The pregnancy rate of carrier (65.4%), noncarrier (73.2%) and nonkarotyped (77.8%) relatives of this sire at their mating as yearlings, did not differ (P>0.10). The pregnancy rate as yearlings of carrier females (65.4%) and contemporary heifers (79.8%) did differ (P<0.05). Comparing the pregnancy rate as yearlings of all descendants (72.0%) of the Simmental sire to contemporary heifers (79.8%), a significant decrease (P<0.05) was found indicating that fertility of this sire may have been lower than other sires or that other factors beside the translocation affected fertility.

Hereditary parakeratosis in shorthorn beef calves.

Parakeratosis was diagnosed in 9 Shorthorn beef calves over a 4-year period. When pedigrees of these calves were analyzed, familial associations were strong. Thirty-six coefficients of relationship among all possible combinations of the 9 affected calves ranged from 0.5 to 39.8% and averaged 15.6%. All affected calves were descendants of bull A. Of 9 affected calves, 6 had bull A in their paternal and maternal pedigrees. The 3 remaining affected calves had bull A in their sire's pedigree and were born to 2 full-sib dams. Seemingly, parakeratosis in this Shorthorn herd was hereditary with the mode of inheritance being that of a simple autosomal recessive.

Anury in two Cairn terriers.

Congenital anury (taillessness) was observed in 2 Cairn Terriers. Fecal staining of the hind limbs was evident in both dogs. A mating of the affected dogs produced a litter of 2 apparently normal pups. The small litter size may have been attributable to lethal gene combinations similar to those described in mice. The radiographic appearance of the caudal and sacral vertebrae was atypical in both tailless dogs. Results of myelography and electrodiagnostic testing of anal sphincter function were normal in one of the dogs. One of the tailless dogs was euthanatized and was found to lack specific muscles and muscle parts responsible for normal defecation, which resulted in fecal staining of the hind limbs. Pedigree analysis revealed the tailless dogs to be closely related and slightly inbred, suggesting a hereditary etiologic factor for anury.

Genetic and phenotypic parameter estimates for scrotal circumference and semen traits in young beef bulls.

Estimated in this study were heritabilities and genetic and phenotypic correlations involving scrotal circumference (SC), percent live sperm, sperm number, sperm concentration, sperm motility, and an overall measure of a bull's potential breeding efficiency. Potential breeding efficiency is a composite trait based on a consideration of sperm concentration, sperm motility, sperm morphology and scrotal circumference. Data used were from three sources. Records on 863 Angus, 753 Polled Hereford, and 302 Simmental bulls were made available through the Missouri Performance-Tested Bull Sale and records on 1169 Polled Hereford bulls came from the American Polled Hereford Association. Information from these first two data sets were used to estimate heritability of scrotal circumference. The third data set was provided by Nichols Farms of Bridgewater, Iowa, and included information from the records of 465 yearling Polled Hereford and 264 yearling Simmental bulls. This latter data set was used to estimate all of the above mentioned parameters. Each data set was kept separately for the purpose of statistical analysis. Parameters were estimated using components from paternal half-sib analysis of variance and covariance. Pooled estimates of heritability for SC, sperm concentration, sperm motility, percent live sperm, sperm number and potential breeding efficiency were 0.51 +/- 0.09, 0.20 +/- 0.13, 0.11 +/- 0.12, 0.00, 0.19 +/- 0.14 and 0.13 +/- 0.12, respectively. Phenotypic correlations involving the six traits were very consistent for the two breeds. Combined across breeds their values ranged from 0.47 for SC and percent live sperm to 0.96 for sperm concentration and potential breeding efficiency. Corresponding genetic correlations were generally positive and high and ranged from 0.65 for SC and sperm motility to 1.14 for sperm number and potential breeding efficiency.

Congenital meningocele-encephalocele in an experimental swine herd.

Fourteen instances of meningocele-encephalocele in an experimental herd were recorded over a 5-year period. Thirteen of these affected animals were subjected to extensive pedigree analyses. Familial associations were strong, and clearly the meningocele-encephalocele in this herd was under genetic influence. However, additional studies are needed to clarify the mode of inheritance and, perhaps, to identify other factors that might be involved.

Chromosomal evaluation of a ewe lamb with atresia ani vaginalis.

Chromosomes of a ewe lamb born with atresia ani vaginalis were examined after a 72-hour culture of peripheral whole blood. The 2n number of chromosomes was 54,XX, with no apparent deviation from normality. Pedigree analysis of the ewe lamb indicated that her sire and dam were only slightly related (Rsd = 0.59%); therefore, the amount of inbreeding of the lamb was small (Fx = 0.30%).

Associations of scrotal circumference with semen traits in young beef bulls.

Associations of percent live sperm, sperm number, sperm concentration, sperm motility, and potential breeding efficiency score with scrotal circumference were studied using data from the records of 465 Polled Hereford and 264 Simmental bulls. Data were subdivided by breed and within breed into three groups according to scrotal circumference (SC) size. Group I bulls had SC measurements <32 cm. Group II included bulls with SC measurements between 32 cm and the mean measurement of the breed (i.e., 35 cm for Polled Hereford and 38 cm for Simmentals). Group III was comprised of bulls with SC values above their respective breed averages. Age and body weight differences were also evaluated in the three groups. Average age differences among bulls in the three groups differed by not more than nine days in the two breeds. Average body weight differences among the three groups were statistically significant (P<0.05) with the maximum difference between any two groups within breed being 80 pounds. Average differences in percent live sperm and sperm number were greater (P<0.05) in Groups II and III than in Group I. For sperm concentration ratings, sperm motility ratings and potential breeding efficiency score, and for both breeds, Group I had a significantly lower (P<0.05) number of bulls classified satisfactory and a significantly greater (P<0.05) number of bulls classified unsatisfactory than did groups II and III.

Scrotal circumference adjustment factors for age and weight differences in beef bulls.

Scrotal circumference measurements were analyzed to develop appropriate adjustment factors for age and body weight differences in beef bulls. Age, body weight, and scrotal circumference measurements were collected on 863 Angus, 753 Polled Hereford, and 302 Simmental bulls from the Missouri tested bull sale, 1169 Polled Hereford bulls from the American Polled Hereford Association, and 465 Polled Hereford and 264 Simmental bulls from Nichols Farms in Bridgewater, Iowa. Within sources, data were subdivided into appropriate subsets and then each subset was statistically analyzed. Adjustment factors to remove differences in scrotal circumference due to age and body weight were developed for bulls of each of the 3 breeds studied.

Brachygnathia in a herd of Angus cattle.

Seven cases of brachygnathia in a single calf crop (28 calves) were observed in an Angus herd. Two of the affected calves, 1 female and 1 male, were necropsied and anatomically described. Breeding histories and results of pedigree analysis involving the 7 affected calves indicated the cause of the defect to be genetic with the mode of inheritance that of a single autosomal recessive gene.

Associations of sire, breed, birth weight, and sex in pigs with congenital splayleg.

Data on 4,411 male and 4,148 female progeny from the University of Missouri-Columbia swine research herd were analyzed to evaluate the associations of sire, breed, weight at birth, and sex of the pigs with the development of congenital splayleg. Statistically significant differences in frequency of splayleg were found among sires and among breeds indicating a genetic influence. Differences in frequencies among male vs female progeny also were found to be statistically significant. The overall frequency among male progeny was 1.74 times that observed among female progeny. Comparison of birth weights of splayleg vs normal pigs showed birth weights to be statistically significantly smaller among affected pigs.

Scrotal circumference adjustment for differences due to age of beef bulls.

Scrotal circumference measurements on 870 Angus, 759 Polled Hereford, and 309 Simmental bulls ranging in age from 484 to 704 days were analyzed to develop an appropriate method of adjustment of scrotal circumference for differences associated with age of the bull. Data were separated by breed, year, and season and then each subset of data was subjected to statistical analysis. Adjustment factors to remove differences due to age were developed for bulls of the three breeds studied.

Chromosome evaluation of Angus calves with unilateral congenital cleft lip and jaw (cheilognathoschisis).

Two purebred Angus calves with unilateral cleft lip and jaw were karyotyped and anatomically described. Both calves, 1 male and 1 female, were from the same farm and were born in March and April 1980. The defect was most pronounced in the female calf. Both calves exhibited an elevated midline of the hard palate. The female calf also manifested characteristics indicative of proportionate dwarfism. Karyotypes were constructed after a 72-hour culture of peripheral blood. The 2N number was 60 with no apparent chromosome abnormality. The coefficient of relationship between the 2 affected calves was calculated to be 0.78%. The cause of the defect could not be ascertained from the limited data available.