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PubMed1981

The relationship between breed and litter size in sheep and maternal serum concentrations of placental lactogen, estradiol and progesterone.

Milk production in sheep is known to be affected by breed and litter size. To investigate a possible hormonal basis for such effects, we measured maternal serum concentrations of placental lactogen, estradiol and progesterone during late gestation in sheep of several breeds and ages. Circulating concentrations of placental lactogen were directly related to litter size in all breeds, with the greatest concentrations being observed in Finnish Landrace ewes bearing three lambs. Among monotocous animals, no significant breed differences were observed, but ewe lambs bearing crossbred fetuses had higher placental lactogen concentrations than ewes of the same breed carrying purebred offspring. Placental lactogen concentrations were similar in all animals bearing twins, except for Corriedale ewes, which had the lowest concentrations. Serum estradiol concentrations 2 to 5 weeks prepartum did not differ between ewes of different breeds or ewes with different litter sizes. Progesterone, like placental lactogen, was related to litter size and, presumably placental mass. The relationship between litter size and placental lactogen concentrations, together with the absence of difference in estradiol secretion, suggests that differences in production of the lactogenic hormone may contribute to the superior lactational performance that has been reported for ewes which bear multiple offspring.

Animals↗
PubMed1985

Performance of crosses among Hereford, Angus and Simmental cattle with different levels of Simmental breeding. III. Heifer postweaning growth and early reproductive traits.

Postweaning growth and early reproductive traits in heifers whose potential for milk production differed were studied during the years 1976 through 1979. Data were collected on 230 heifers raised by greater than or equal to 3-yr-old Hereford dams. Heifers were comprised of the following breed groups: Hereford (HH), Angus-Hereford (AH), 25% Simmental-75% Hereford (1S3H) and Simmental-Hereford (SH). Postweaning growth rate during a 140-d period was greatest for SH heifers (.75 kg/d), intermediate for AH and 1S3H groups (.70 and .68 kg/d, respectively) and slowest for HH heifers (.64 kg/d). At 1 yr of age, SH heifers were heavier, taller and had larger pelvic areas than all other groups (P less than .01). Least-squares means for yearling weight, hip height and pelvic area for HH, AH, 1S3H and SH heifers were 283, 303, 298 and 317 kg; 111, 112, 114 and 118 cm, and 132, 136, 139 and 148 cm2, respectively. Ninety-one percent of the heifers reached puberty by the end of the breeding period. Crossbred heifers reached puberty at younger ages and had higher pregnancy rates than HH heifers (P less than .01). Least-squares means for pubertal age, weight and height for HH, AH, 1S3H and SH breed groups were, respectively, 407, 371, 382 and 368 d; 300, 302, 305 and 313 kg, and 115, 114, 117 and 119 cm. Percentage of heifers reaching puberty by 14 mo of age was 64, 99, 85 and 94 for HH, AH, 1S3H and SH, respectively. Respective pregnancy rates were 59, 90, 77 and 86%, but were not significantly different among breed groups when only heifers reaching puberty by the end of the breeding period were studied. No differences among breed groups were found for date of pregnancy.

Animals↗
PubMed1986

Between- and within-breed genetic analysis of calving traits and survival to weaning in beef cattle.

Data for gestation length, birth weight, calving difficulty (percent assisted) and survival from birth to weaning were analyzed from 4,639 calves by 290 sires of 14 Bos taurus breeds (Hereford, Angus, Jersey, South Devon, Limousin, Simmental, Charolais, Red Poll, Brown Swiss, Gelbvieh, Maine Anjou, Chianina, Pinzgauer and Tarentaise) mated to Hereford and Angus cows. The calves were produced over a 7-yr period in a germ plasm evaluation program. Variance components were estimated for breed of sire (sigma 2b), sire within breed of sire (sigma 2s) and progeny within sire (sigma 2w) random effects. Estimates of sigma 2b and sigma 2s direct genetic variance were similar for gestation length and calf survival. Estimates of sigma 2b genetic variance were greater than for sigma 2s for birth weight and calving difficulty. Estimates of total heritability [h2t = 4(sigma 2b + sigma 2s)/(4 sigma 2b + sigma 2s + sigma 2w)] and within-breed heritability (h2w = 4 sigma 2s/sigma 2s + sigma 2w) indicated that gestation length (h2t = .77, h2w = 64) and birth weight (h2t = .79, h2w = .46) are under a high degree of direct genetic control, calving difficulty (h2t = .42, h2w = .21) is under a moderate degree of direct genetic control and calf survival (h2t = .11, h2w = .07) is under a low degree of direct genetic control. Estimates of genetic correlation for between (rb) - and within-breed (rg) sources of genetic variation were comparable in direction, but tended to be stronger between than within breeds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Comparison of cattle of a five-breed diallel: size, growth, condition and pubertal characters of second-generation heifers.

Monthly weights, heights and condition scores and measurements taken at the time of puberty were utilized to estimate effects of breed-type and heterosis on characters related to growth, size and puberty of second-generation heifers of a five-breed diallel involving Angus, Brahman, Hereford, Holstein and Jersey. One group of heifers was maintained on pasture with supplemental feed; two other groups were fed in individual pens starting at weaning and 1 yr of age, respectively. A model including main effects of breed-type, sire within breed-type, management, parity of dam and birth-season was used for analyzing all characters. Breed-type tested with sire within breed-type was significant for all characters except ADG from 360 to 450 d. Straightbred and crossbred means were larger for the second generation than for the first, presumably due to management and(or) year effects. Heterosis generally was positive and, when expressed as a percentage, decreased with age, which is in agreement with other research reports. Holsteins and Brahmans were largest for growth and size characters, whereas Jerseys were smallest. Jerseys were the youngest, lightest and shortest at puberty, whereas Brahmans were oldest, heaviest and tallest.

Analysis of Variance↗
PubMed2006

Trends in calving ages and calving intervals for dairy cattle breeds in the United States.

Trends since 1980 for calving age and calving interval, 2 factors that influence herd life, were examined by parity for 5 breeds of US dairy cattle. Calving data were from cows with records that passed edits for USDA genetic evaluations and were in herds that remained on Dairy Herd Improvement test. First-calf heifers calved at progressively younger ages over time, but the age decline was less for later parities because of longer calving intervals. Breed differences for calving age were evident for all parities; current mean age at first calving ranged from 24 mo for Jerseys to 28 mo for Ayrshires. Mean calving age across all parities declined over time for all breeds, primarily because of increased turnover rate, and ranged from 48 mo for Holsteins to 54 mo for Ayrshires. Across parity, annual increase in calving interval was reasonably consistent (0.90 to 1.07 d/yr) for all breeds except Jersey (0.49 d/yr). Within parity, regressions of calving interval on year were generally similar to overall breed trend. Breed means for first calving interval across time ranged from 390 d for Jerseys to 407 d for Brown Swiss.

Aging↗
PubMed2006

A method to define breeding goals for sustainable dairy cattle production.

The objective of this study was to present a method to define breeding goals for sustainable dairy cattle production by adding nonmarket values to market economic values for functional traits in the breeding goal. A nonmarket value can represent the value of improved animal welfare or societal influences for animal production. The nonmarket value for mastitis resistance, conception rate, and stillbirth were derived based on how much farmers or breeding companies were willing to lose in selection response for milk yield to improve functional traits. The desired response for milk yield corresponding to a given percent loss was obtained using desired gain indices. By allowing a 5% loss in the selection response for milk yield, the nonmarket value was found to be 40.4 euro for mastitis resistance, 16.1 euro for conception rate, and 9.7 euro for stillbirth. The nonmarket value increased proportionally with increasing loss in the selection response for milk yield, but the selection response was lower for conception rate than for mastitis resistance because of differences in market economic value and heritability. To increase the response for conception rate, the nonmarket value was also derived for 2 situations, in which the desired responses for milk yield, mastitis resistance, and conception rate were specified. The method can be used to define breeding goals for sustainable production and to increase the response for traits that are at critically low levels. When defining breeding goals for sustainable production, breeding organizations should predict the selection response based on market economic value and add non-market value for traits with unacceptable selection responses.

Animals↗
PubMed1984

Seasonal breeding in United States dairy goats.

Effects of breed, region, and interaction of breed with region on seasonality of breeding in United States dairy goats were studied. Reproductive performance data were from 76,350 official National Cooperative Dairy Herd Improvement Program records on Alpine, La Mancha, Nubian, Saanen, and Toggenburg does. Variables were month of conception, month of kidding, days open, and deviation of kidding date from March 1. Four northern regions were: 1, greater than or equal to 45 degrees latitude; 2, 40-45 degrees; 3, 35-40 degrees; and 4, less than or equal to 35 degrees. About 20% of Nubians conceived from January through August, whereas only 10% of Alpines and of Toggenburgs conceived during those months. La Manchas conceived most frequently in November whereas other breeds conceived most frequently in October. Each breed kidded most frequently in March. In September and October, 3 to 4% more conceptions occurred in Regions 1 and 2 than in 3 and 4, whereas in November, 7.3% fewer conceptions occurred in Regions 1 and 2 than in 3 and 4. In January, 13.2% of kiddings occurred in Region 4 compared to 5.6% in Region 1. Similarly, during July through December, proportionally more kiddings (11.8%) occurred in Region 4 than in Region 1 (5.2%). In the range of latitudes studied, differences in degree of seasonality due to breed, region, and interaction, although significant, were minor.

Animals↗
PubMed1994

Effects of correction for heterogeneity of variance on bias and accuracy of breeding value estimation for Dutch dairy cattle.

Data on 305-d milk yield from the Dutch dairy evaluation were used to obtain breeding value estimates from an animal model for 1984 to 1992. Changes in sire evaluations were investigated for bias and realized accuracy. Evaluations based on progeny records were generally lower than their expectation based on parent average. The average decrease was 157 kg for Black and White bulls and 73 kg for Red and White bulls. Evaluations based on test daughters changed about -50 kg when second and third lactations became available, but estimates for breeding value changed insignificantly when records on daughters from the breeding period of the bull were used. The standard deviation of changes from evaluations for first to second batch was about 14% larger than expected from population parameters. Breeding values of imported bulls, based on Dutch data, decreased 75 kg when more information became available in subsequent evaluations. Heterogeneity of variance was estimated by a quasi-likelihood approach with a model that accounted for sampling variance on estimates of variances within herd. The coefficient of variation of the variances within herd-year was 31%. A simple method for standardization of variances within herd-year decreased bias of parent averages by about 20%, and fluctuations of breeding values were within the expected range. A correction for heterogeneity of variance within herd may not remove all bias of parent averages, but a general improvement of bias and accuracy of breeding values can be expected.

Analysis of Variance↗
PubMed1998

Optimizing pure line breeding strategies utilizing reproductive technologies.

The development of new reproductive techniques has had a great effect on schemes for dairy cattle improvement; AI resulted in progeny-testing schemes, and, more recently, multiple ovulation and embryo transfer has resulted in nucleus breeding schemes. In traditional breeding schemes, the use of multiple ovulation and embryo transfer resulted in only small increases of genetic gains because the selection intensity of bull dams was already high, but the selection intensity of cows in nucleus breeding schemes increased considerably. This increase makes nucleus schemes very competitive, especially when in vitro maturation and fertilization is used to increase female reproductive rates further. The increased genetic gain results in the selection of young females (i.e., optimal generation intervals are shortened). The combined effect of multiple ovulation and embryo transfer and shorter generation intervals increases the rate of gain by approximately 15% but also increases the rate of inbreeding and variances of the selection response (i.e., the risk of the breeding scheme) by about 80%. Recently, selection methods have been developed to reduce the rates of inbreeding or the variance of the selection response in breeding schemes. A scheme that maximized the selection differential while constraining the rate of inbreeding yielded about 30 to 60% more selection response than selection for BLUP estimated breeding value at the same rate of inbreeding. For the future, the combination of juvenile predictors of genetic merit (e.g., DNA markers) and techniques that further increase female reproductive rates seem very promising methods to increase the rates of genetic gain. As an example, the genetic gain of an optimized hybrid nucleus scheme could be increased 24% by the combined use of juvenile predictors and in vitro maturation and fertilization. Fertilization of fetal embryos was predicted to increase rates of gain by up to 18%.

Animals↗
PubMed1998

Breed group effects on milk production of Brazilian crossbred dairy cows.

Lactation records (n = 2362) of 1402 crossbred cows in 22 cooperating dairy herds in southeastern Brazil were evaluated. Cows were mixtures of Zebu (Gir, Guzera, and unknown) and European breeding (mostly Holstein). Lactation milk yields were expressed as total, 3050-d, or deviated 305-d yields, either adjusted or unadjusted for days in milk (DIM). Mean DIM was 280. Arithmetic means unadjusted for DIM were 1942, 1666, and 5 kg per record. Milk yields of daughters from sires of 6/8 and 7/8 European breeds were higher than yields of daughters from sires of 5/8 European breeds when data were either adjusted or unadjusted for DIM. The differences associated with breed group of sire were only slightly reduced when records were adjusted for DIM. There was no evidence of a decline in milk yield as the fraction of European breeding of the sire increased from 6/8 to 7/8. For a given breed group of sire, whether the grandsire was purebred or crossbred had no detectable effect. These results should be useful in determining strategies for crossbreeding of dairy cows in tropical areas, particularly when crossbred sires are used.

Animals↗
PubMed1976

Preliminary study of the effects of feeding ethyl mercury chloride on four breeds of chickens.

Different breeds of chickens namely Single Comb White Leghorn (S.C.W.L.), New Hamsphire (N.H.), Iraqi (IRQ) and a cross (CRS.) S.C.W.L. X N.H. X IRQ. were housed in small pens (20 females and 2 males each) and given, in the diet, 40% wheat treatmed with ethyl mercury chloride, for 88 days. Throughout the whole experiment all birds remained active and showed no symptoms of toxicity. The Iraqi breed was significantly higher than the other breeds with respect to egg production. The results also indicated that mercury in egg white is almost three times as much as that in the yolk, although there was no significant difference between the breeds. The liver and kidney of the four breeds tended to accumulate the highest amount of mercury. Significant differences appeared between sexes according to liver and kidney. White Leghorn and local breeds behaved the same, but N.H. had the highest concentration of mercury in most tissues.

Animals↗
PubMed1998

Domestic Aedes aegypti breeding site surveillance: limitations of remote sensing as a predictive surveillance tool.

This project tested aerial photography as a surveillance tool in identifying residential premises at high risk of Aedes aegypti breeding by extending the use of a recently developed, ground-based, rapid assessment technique, the modified Premise Condition Index (PCI2). During 1995, we inspected 360 premises in Townsville, Australia for Ae. aegypti breeding, and PCI2 scores were recorded. The PCI2 values were also estimated from 1:3,000 color and infrared aerial photograph interpretation for the same premises. We found that shade levels can be accurately identified from both color and infrared images, and the PCI2 can be accurately identified from infrared photographs. Yard conditions, however, cannot be accurately identified from either aerial photograph type. The airborne PCI2 did not significantly correlate with breeding measures, and logistic regression further demonstrated that neither aerial photograph type allows the accurate prediction of Ae. aegypti breeding risk. Therefore, the ability of low-level aerial photography to enhance Ae. aegypti breeding site surveillance is at present limited, with ground surveillance remaining our most reliable tool for identifying the probability of Ae. aegypti breeding in the residential environment.

Aedes↗
PubMedDate not supplied

Breed susceptibility for developmental orthopedic diseases in dogs.

A large-scale epidemiological study was conducted to determine breeds at risk for 12 developmental orthopedic diseases (DODs). Developmental orthopedic diseases investigated included canine hip dysplasia (CHD); craniomandibular osteopathy (CMO); fragmented coronoid process; hypertrophic osteodystrophy; Legg-Calvé-Perthes disease; osteochondrosis of the medial humeral condyle, caudal humeral head, femoral condyles, and talar trochlear ridges; panosteitis; patella luxation; and ununited anconeal process. Dogs that were diagnosed with any one of the diseases of interest at any of 10 veterinary teaching hospitals participating in the Veterinary Medical Database from 1986 to 1995 were included as cases. Odds ratios and corresponding 95% confidence intervals were calculated to determine risk. Frequency of diagnosis during the 10-year period ranged from 35 cases (CMO) to 10,637 cases (CHD). The number of breeds at increased risk for a disease ranged from one (CMO) to 35 (CHD). Breed susceptibility for a DOD may suggest a genetic component in the disease etiology. The results of this study serve to increase veterinarians' awareness of breeds susceptible to DODs and may facilitate the control of such diseases by identifying breeds that might benefit from breeding programs or environmental intervention such as dietary modification.

Animals↗
PubMed2001

Synaptonemal complex analysis of the Holstein-Friesian, Piemontese and Simmental breeds of Bos taurus taurus.

The synaptonemal complex (SC) of specimens of Bos taurus taurus from the Holstein-Friesian, Piemontese, and Simmental breeds, was analysed. The analysis included quantification of the frequency of various types of abnormalities in the SC, and the frequency of cells with SC abnormalities. All animals had 29 autosomal bivalents and one sexual bivalent and the most frequently recorded abnormality was pairing failure. The number of cells with abnormalities in the Holstein-Friesian breed was 29.41%, in the Piemontese breed was 30.00% and in the Simmental breed it was 29.54%. The subspecies Bos taurus taurus had 29.63% of cells showing abnormalities with 57.33% of these abnormalities occurring in zygotene and 42.67% occurring in pachytene. Statistical analyses showed that there were no significant differences in the number of cells with SC abnormalities among the breeds studied. The frequency of cells with abnormalities, and the efect on the fertility of the Holstein-Friesian, Piemontese and Simmental breeds are discussed.

Animals↗
PubMed2001

Population-based incidence of mammary tumours in some dog breeds.

Data from two population-based studies in four Norwegian counties were used to calculate the crude incidence of mammary tumours, and the age- and breed-specific incidence of mammary tumours in female dogs of three different breeds. The largest study comprised 14401 histologically verified tumour cases from four counties covered by the Norwegian Canine Cancer Register. The registry covers about 25% of the total Norwegian dog population. The second study was a census in Norway that was sent to all owners of the following breeds: boxers, bichon frisé and Bernese mountain dogs, to estimate the age distribution of the female dog population at risk of developing mammary tumours. The crude incidence of malignant mammary tumours in female dogs of any breed was 53.3%. The highest relative risk ratio of mammary tumours was found in boxers, cocker spaniels, English springer spaniels and dachshunds. The mean age of histologically diagnosed mammary tumours was 7.9 years in boxers and 7.8 years in springer spaniels, compared with 8.8 years in all other breeds. In the four Norwegian counties from 1992 to 1997, the population-based incidence rates (for all ages) of malignant mammary tumours per 1000 female dogs per year were 35.47 in boxers, 3.87 in Bernese mountain dogs and 17.69 in bichon frisé. Mammary cancer is the most common tumour in female dogs in Norway, and represents a population of almost entirely reproductively intact females. The age-specific incidence rates for mammary cancer vary considerably among the three breeds that were studied in detail.

Age Distribution↗
PubMed2001

Observations on the breeding habitat of Aedes species in the steel township, Rourkela.

Prompted by report of large number of dengue fever cases in township of Rourkela steel plant, entomological surveys were carried out to know the distribution and extent of Aedes breeding in and around the dengue fever affected areas. Out of 2062 water containers searched, 819 were positive for Aedes larvae. The house index (HI), container index (CI) and Breteau index (BI) were 53.4, 39.7 and 118.5 respectively. 27.9% of the houses had single breeding habitats. The breateau index of single storeyed houses and double storeyed buildings was 149.8 and 54.6 respectively, showing that the single storeyed houses have more potential for Aedes breeding. The breeding preference ratio (BPR) was highest for plastic containers. Three species of Aedes were found breeding in different habitats and Aedes aegypti was found breeding in coolers, cement tanks, tyres and miscellaneous containers with a prevalence rate of 13.2%. The role of entomological surveillance and health education has been highlighted for the control of disease through community participation.

Aedes↗
PubMed2001

Breeding for improved disease resistance in organic farming--possibilities and constraints.

Lowered incidences of disease may be reached in several ways: management and rearing measures, vaccination programmes and preventive medications as well as breeding for improved disease resistance. Here the focus is on breeding for improved resistance to infectious diseases. In comparison to conventional farming, one has to acknowledge that the spectrum of diseases in animals reared under organic conditions is different and that the proportion of the breeding stock of animals in organic farming is considerably smaller. There are at least four different approaches that may be used in breeding towards resistance to infectious diseases. The most obvious is to record disease incidence in the progeny and select those parents that produce the progeny with the lowest incidences of disease. Another approach is to use breeders possessing certain major histocompatibility complex antigens suggested being associated with resistance to certain infections. A third approach is to analyse the heritability of a set of immune functions or related traits crucial for resistance to infections and then use the traits with high heritability in breeding programmes. Finally, one may genetically select animals for high immune response using an index that combines estimated breeding values for several immunological traits. Examples of these various approaches are given and the feasibility for using these in organic farming are discussed.

Animal Diseases↗
PubMed2003

[Ecological surveillance on breeding ground for Oncomelania hupensis snails in the areas prevalent with islet-type schistosomiasis using remote sensing technology].

OBJECTIVE: To probe rational indices suitable for ecological surveillance on breeding ground for Oncomelania hupensis snails in areas prevalent with islet-type schisitosomiasis using remote sensing technology. METHODS: Three adjacent islets, prevalent with islet-type schistosomiasis, along the Yangtze River within the boundaries of Dongzhi County, Anhui Province were selected as study field for remote sensing analysis. Multi-spectral data were composed and non-supervisedly classified in computer with Idisi software for remote sensing analysis. Values of the normalized difference vegetation index (NDVI), green vegetation index (GVI), bright index (BI), which reflect the greenness and brightness of landscape, were also calculated. Finally, all the results were comprehensively analyzed, combined with data from the field investigation. RESULTS: NDVI, GVI and BI could depict characteristics of the landscape quantitatively. Values of NDVI, BI and GVI were varied in different types of landscapes, and 95% confidence interval of these values suitable for breeding of snails was 0.0522 approximately 0.3566, 2.4162 approximately 28.2672 and 29.3404 approximately 40.3135, respectively. Classification of NDVI showed that type 5 anf type 6 were main breeding ground for snails, and type 4 with values of NDVI from 0 to 0.1 was potential areas for snail propagation. Classification of GVI showed that types 5, 6 and 7 were main breeding ground for snails, and also type 4 with values of GVI from 2 to 10 was potential areas for snail propagation. Both NDVI and GVI showed type 2 and type 3 were temporarily not suitable for snail breeding. CONCLUSION: Index figures of NDVI and GVI re-formed by reasonable classification could reflect not only breeding ground for snails and range of the areas for snail propagation in islets, but also their evolving rules, i.e., status of new marshland formation and vegetation growth.

Animals↗