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PubMed1987

Genotype x environment interactions involving proportion of Brahman breeding and season of birth. II. Postweaning growth, sexual development and reproductive performance of heifers.

Postweaning growth, sexual development and reproductive traits were evaluated over a 3-yr period on 201 spring-born and 180 fall-born crossbred heifers with 0, 1/4 or 1/2 Brahman breeding. The proportion of Brahman breeding X season of birth interaction was significant for five traits (average daily gain weaning to yearling, yearling condition score, percentage of heifers detected in estrus, prebreeding condition score and percentage of heifers that became pregnant) and was not significant for six traits (yearling weight, hip height and conformation score, age and weight at puberty and prebreeding weight. Among spring-born heifers, 1/4 and 1/2 Brahman heifers outgained (P less than .05) 0 Brahman heifers from weaning to yearling by 50 and 66 g/d, respectively; among fall-born heifers, 1/4 and 1/2 Brahman heifers outgained (P less than .05) 0 Brahman heifers by 41 and 104 g/d, respectively. Yearling weight of 1/2 Brahman heifers was 13 and 10 kg heavier (P less than .05), respectively, than 0 and 1/4 Brahman heifers. Yearling hip height of 1/4 and 1/2 Brahman heifers were 1.9 and 5.7 cm taller (P less than .05), respectively, than 0 Brahman heifers. Weight prior to the start of the breeding season were similar among crossbred heifer groups and spring-born heifers were 66 kg heavier (P less than .05) than fall-born heifers. The percentage of heifers that became pregnant was similar among spring-born crossbred heifer groups, whereas among fall-born heifer groups 1/4 and 1/2 Brahman heifers were 25.2 and 49.4 percentage points lower (P less than .05), respectively, than 0 Brahman heifers.

Animals↗
PubMed1988

Productive longevity of first-cross cows produced in a five-breed diallel: I. Reasons for removal.

Data from 498 cows of 15 breed-types produced in a five-breed diallel (reciprocals pooled) including Angus, Brahman, Hereford, Holstein and Jersey were analyzed for differences in productive longevity, mean life span and reasons for removal from the herd over approximately 14 yr. The only culling related to production was of cows that did not give birth to at least one live calf every 24 mo. Otherwise, cows were only removed when they appeared to be incapable of weaning another live calf. The average age at removal, estimated from linear regression, was 3,470 d, with values ranging from 2,174 d (Jersey) to 4,087 d (Angus-Brahman). Longevity of crossbred cows was greater than that of purebred cows (P less than .001). Purebred cows usually had higher initial rates of removal than crossbred cows. Estimates of mean longevity from the nonlinear regression resembled the results of the linear regression analysis; mean life spans ranged from 6.2 yr (Jersey) to 14.6 yr (Angus-Brahman). The major reason for removal of Brahman and Brahman-cross cows was for reproductive reasons. Angus and Angus-cross cows were culled more frequently for structural unsoundness; Hereford cows had a higher incidence of cancer eye, calving difficulty and mammary problems; cows with 100% dairy breeding had exceptionally high susceptibility to diseases and mineral imbalance.

Animals↗
PubMed1989

Relationship between fasting heat production, body composition and tissue distribution, in mature ewes from seven breeds.

To evaluate the relationship between measures of maintenance and body composition, data were collected on 12 mature, nonpregnant, nonlactating ewes from each of seven breeds following 6 wk of ad libitum (AL) or maintenance (MN) feeding (six per breed-level). After fasting 56 h, fasting heat production (FHP) was measured for each of 42 pairs of ewes over a 16-h period. Ewes then were slaughtered and the empty body divided into visceral organs and blood (ORB); gastrointestinal tract and internal fat (GIF); head, hooves and pelt (HHP); and carcass (CAR). Each fraction was chemically analyzed for water, fat, ash and (by difference) fat-free dry organic matter (FFDOM or protein). Correlations with FHP/d were highest (.86 to .87) for weights of empty body and body water or lean (FFDOM + water) and were lower (.77) for weight of empty body fat. Best nonlinear LWT predictors of FHP/d were LWT.63 and water.71 or lean.71 (R2 = .76). Correlations of metabolic FHP (kcal/kg.75) with percentage lean and fat, respectively, were .53 and -.55 for the empty body and .60 and -.60 for the GIF fraction. For AL ewes, the better predictors of FHP/d were weights of lean in GIF + ORB (R2 = .88, ESD = 106), live weight (LWT) plus fat and lean in GIF fraction (R2 .88, ESD = 112) or LWT plus fat in HHP and GIF fractions (R2 = .90, ESD = 103). For MN ewes, LWT alone was as accurate (R2 = .80, ESD = 123) as any combination of components. Breed mean daily FHP was predicted very accurately (R2 = .94) from total weight of empty body lean plus the proportion of total body lean located in the GIF fractions.

Adipose Tissue↗
PubMed1989

Effects of creep feeding, zeranol implants and breed type on beef production: I. Calf and cow performance.

A 2-yr study was conducted to evaluate the effects of a high-energy creep feed, preweaning zeranol implants and breed type on calf and cow performance. Two hundred calves sired by Brahman and Romana Red bulls out of Angus and Angus x Brown Swiss reciprocal crossbred (F1) dams were stratified by breed type and sex to three creep treatments: no creep feed (NC); long-term creep (LC), creep-fed from 56 to 210 d of age (weaning); and short-term creep (SC), creep-fed from 146 to 210 d of age. Alternate calves within sex, breed type and creep treatment were implanted with 36 mg of zeranol at an average of 56 d and reimplanted 90 d later. The LC and SC calves had heavier (P less than .001) 210-d weights than NC calves (264 and 257 vs 231 kg, respectively), and the LC calves were heavier (P less than .001) at 146 d than NC calves. The LC calves had higher (P less than .001) ADG from 118 to 210 d of age and higher 146 and 210-d condition scores than did NC calves. Pregnancy rate was not affected (P greater than .46) by creep treatment of calf. Zeranol implants increased (P less than .01) 146- and 210-d weights (184 vs 175 kg and 259 vs 243 kg) and ADG during all periods to weaning. Brahman-sired calves had higher (P less than .005) 146- and 210-d weaning weights and frame scores than Romana Red-sired calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1989

Efficacy of methods used to test fertility of beef bulls used for multiple-sire breeding under range conditions.

A study was conducted during the 1982, 1983 and 1984 breeding seasons with 277 crossbred bulls, 1 to 3 yr of age, that were evaluated for physical soundness, testicular development, seminal quality, and both sexual and social behavior immediately before exposure to crossbred cow herds ranging in size from 89 to 329 cows. Crossbred cow herds were exposed to 4 to 24 bulls per breeding group (mean of 14) at a mean female: male ratio of 21.2 +/- .6:1 under extensive range conditions for 31 to 62 d (mean 46.6 d). All resulting calves were blood-typed to determine the number of calves sired by each bull as an estimate of his fertility. The mean number of calves sired by 1- (n = 116), 2- (n = 126) and 3-yr-old (n = 35) bulls was 4.7 +/- .1, 8.2 +/- .1 and 10.5 +/- .1, respectively. A regression model for predicting bull fertility under multiple-sire, range breeding conditions was selected that accounted for 29% of the total variance in fertility. Similar models accounted for a greater proportion of variance in fertility of 1-yr-old (37%) than of 2-yr-old bulls (22%). Due to the large amount of unexplained variation, the model could not predict individual bull fertility precisely. However, this study demonstrated that selection of herd sires with large scrotal circumference, low backfat thickness, low levels of primary sperm defects, and a low number of mounts in combination with a moderate number of services during libido testing would be expected to improve fertility of beef bulls used under extensive range conditions.

Adipose Tissue↗
PubMed2003

The effect of breed, parity, and stage of lactation on conjugated linoleic acid (CLA) in milk fat from dairy cows.

Dairy products are the main source of conjugated linoleic acid (CLA), a functional food component with health benefits. The major source of cis-9, trans-11 CLA in milk fat is endogenous synthesis via delta9-desaturase from trans-11 18:1, with the remainder from incomplete rumen biohydrogenation of linoleic acid. Diet has a major influence on milk fat CLA; however, effects of physiological factors have received little attention. Our objectives were to examine milk fat content of CLA and the CLA-desaturase index with regard to: 1) effect of breed, parity, and stage of lactation, and 2) variation among individuals and the relationship to milk and milk fat. Holstein (n = 113) and Brown Swiss (n = 106) cows were fed a single diet and milk sampled on the same day to avoid confounding effects of diet and season. Frequency distributions demonstrated that milk fat content of CLA and CLA-desaturase index varied over threefold among individuals, and this needs to be considered in the design of experiments. Holsteins had a higher milk fat content of CLA and CLA-desaturase index, but breed differences were minor. Parity and days in milk also had little or no relationship to the individual variation for these two CLA variables. Breed, parity, and days in milk accounted for < 0.1, < 0.3, and < 2.0% of total variation in CLA concentration in milk fat, respectively. Milk fat content of CLA and CLA-desaturase index were essentially independent of milk yield, milk fat percent, and milk fat yield. We speculate that the basis for the genetic variation among individuals is related to rumen output of trans-11 18:1 and to a lesser extent cis-9, trans-11 CLA, and to the tissue amount and activity of delta9-desaturase.

Animals↗
PubMed2004

The use of integer programming to select bulls across breeding companies with volume price discounts.

Optimization programs are currently used to aid in the selection of bulls to be used in herd breeding programs. While these programs offer a systematic approach to the problem of semen selection, they ignore the impact of volume discounts. Volume discounts are discounts that vary depending on the number of straws purchased. The dynamic nature of volume discounts means that, in order to be adequately accounted for, they must be considered in the optimization routine. Failing to do this creates a missed economic opportunity because the potential benefits of optimally selecting and combining breeding company discount opportunities are not captured. To address these issues, an integer program was created which used binary decision variables to incorporate the effects of quantity discounts into the optimization program. A consistent set of trait criteria was used to select a group of bulls from 3 sample breeding companies. Three different selection programs were used to select the bulls, 2 traditional methods and the integer method. After the discounts were applied using each method, the integer program resulted in the lowest cost portfolio of bulls. A sensitivity analysis showed that the integer program also resulted in a low cost portfolio when the genetic trait goals were changed to be more or less stringent. In the sample application, a net benefit of the new approach over the traditional approaches was a 12.3 to 20.0% savings in semen cost.

Animals↗
PubMed2004

Short communication: effect of leptin gene polymorphisms on breeding value for milk production traits.

New molecular techniques focused on genome analysis open new possibilities for complex evaluation of economically important traits in farm animals. Milk production traits are typical quantitative characteristics controlled by a number of genes. Mutations in their sequences may alter animal performance as well as their breeding values. In this study, we investigated the effect of 3 restriction fragment length polymorphisms (RFLP): HphI, Kpn2I, and Sau3AI in the leptin gene, on bull breeding values for milk, fat, and protein yield, and fat and protein content. One hundred seventeen Polish Black and White AI bulls were genotyped. Pedigree analysis indicated a relatively close relationship between the bulls. Statistical analysis indicated that the HphI polymorphism has a significant effect on milk and protein yield. Animals with the TT genotype had approximately 2x higher estimated breeding values for milk and protein yields. No effect was found for the other 2 polymorphisms.

Animals↗
PubMed2005

Derivation of sustainable breeding goals for dairy cattle using selection index theory.

The objective was to present 2 methods for the derivation of nonmarket values for functional traits in dairy cattle using deterministic simulation and selection index theory. A nonmarket value can be a value representing animal welfare and societal influences for animal production, which can be added to market economic values in the breeding goal to define sustainable breeding goals. The first method was restricted indices. A consequence of adding a nonmarket value to a market economic value for a given functional trait is less selection emphasis on milk yield. In the second method, the loss in selection response in milk resulting from greater emphasis on functional traits was quantified. The 2 methods were demonstrated using a breeding goal for dairy cattle with 4 traits (milk yield, mastitis resistance, conception rate, and stillbirth). Nonmarket values derived separately using restricted indices were 0.4 and 2.6 times the value of market economic values for mastitis resistance and conception rate, respectively. Nonmarket values for mastitis resistance and conception rate were both lower when derived simultaneously than when derived separately. This was due to the positive genetic correlation between mastitis resistance and conception rate, and because both traits are negatively correlated with milk yield. Using the second method and accepting a 5% loss in selection response for milk yield, nonmarket values for mastitis, conception rate, and stillbirth were 0.3, 1.4, and 2.9 times the market economic values. It was concluded that the 2 methods could be used to derive nonmarket values for functional traits in dairy cattle.

Animals↗
PubMed2006

Variation in fatty acid contents of milk and milk fat within and across breeds.

The aim of this research was to study the potential for selection of cows with a higher nutritional quality of milk fat by studying the differences in fatty acid profiles within and across the following breeds: Dual Purpose Belgian Blue, Holstein-Friesian, Jersey, Montbeliarde, and non-Holstein Meuse-Rhine-Yssel type Red and White. Six hundred milk samples from 275 animals were taken from 7 herds. Several types of fatty acids in milk and milk fat were quantified using mid-infrared spectrometry and previously obtained calibration equations. Statistical analyses were made using a mixed linear model with a random animal effect. The variance components were estimated by using REML. Results showed breed differences for the fatty acid profile. The repeatability estimate obtained in the present study may suggest the existence of moderate additive genetic variance for the fatty acid profile within each breed. Results also indicated variation for each analyzed milk component in the whole cow population studied. Genetic improvement of the nutritional quality of milk fat based on fatty acid profiles might be possible, and further research and development are warranted.

Animals↗
PubMed1983

Selecting groups of sires by computer to maximize herd breeding goals.

A computerized linear program, MAXBULL, selects sires for dairymen to obtain maximum Predicted Difference milk while maintaining other goals. Goals are minimum average Predicted Differences fat percent and type, six individual type traits, and maximum average semen price. Individuals traits for bulls are coded +1, 0, -1 according to evaluations from breed associations. Dairymen restrict bulls offered to the program by specifying unacceptable repeatability, Predicted Differences, and price. They further control breed, stud organizations, minimum bull numbers, use of sires with low repeatability (less than 50%) and without type proofs, and maximum use of specific bulls and sons of sires. Goals for individual type are specified as the percentage of cows in the herd needing improvement in each trait. The solution contains at least that percentage of semen from sires coded +1 in each trait. The dairyman receives a count of bulls surviving each of his edits, a reiteration of his goals, a list of recommended units and all information for each sire, averages for all traits weighted by the units recommended, and the expected increase in Predicted Difference milk from relaxing each goal one unit. MAXBULL has led to individualized breeding programs characterized by reasonable goals, balance in emphasis among traits, and stability in goals over time.

Animals↗
PubMed1983

Breeding practices on Illinois Holstein farms.

Questionnaires requesting breeding information were mailed to 1,148 Illinois Holstein herds in the Dairy Herd Improvement program. A total of 591 questionnaires (51%) were returned. Dairy producers with herds producing over 7,100 kg of milk returned 64% of their questionnaires whereas 34% of dairy producers with herds producing less than 5,900 kg returned their questionnaires. State average and standard errors were: 23 +/- 1 bulls used per 100 cows, 78 +/- 2% dairy producers select the bulls, 96 +/- 1% herds use artificial insemination, 2.1 +/- .1 artificial insemination organizations per herd, 29 +/- 2% herds participate in young sire testing programs, 87 +/- 1% farmers consider calving ease indicators in mating heifers, and 17 +/- 2% farmers consider calving ease indicators in mating cows. Breeding practices positively associated with increasing rolling herd average milk production were number of bulls per herd and per 100 cows, self as bull selector, use of artificial insemination, number of artificial insemination organizations, and participation in young sire testing programs. Three breeding practices were negatively associated with increasing rolling herd average milk production: artificial-insemination technician as bull selector and consideration of calving ease for mating heifers and cows. Dairy producers also were asked to rate the emphasis placed on traits in bull and cow selection. For bull selection, udder conformation and Predicted Difference milk were most important. In cow selection, milk production, followed by udder conformation, feet and legs, and fat percentage, was the most important trait.

Animals↗
PubMed1990

Effect of variability in response to superovulation on donor cow selection differentials in nucleus breeding schemes.

The effectiveness of nucleus breeding schemes based on multiple ovulation and embryo transfer in practice is highly dependent upon the achieved reproductive rate. This study quantifies the effects of donor cow variability in response to superovulation (random and phenotypically correlated with milk yield) and failure rates (proportion of selected cows producing no transferable embryos) on the mean and variance of realized female selection differentials as affected by herd size, average embryo yield, and the coefficient of variation for embryo yield. Results show that differences in failure rates (0 to 40%) reduced realized female selection differentials up to 64%. The existence of a negative phenotypic correlation (-.3) between donor cow embryo yield and milk yield caused smaller reductions (up to 19%). Variability in realized female selection differentials is largest for small nucleus units and should not be neglected when planning the establishment of a nucleus breeding unit. The use of multiple flushes rather than a single flush per cow to produce the same average number of transferable embryos can reduce the variability in realized selection differentials but increases generation interval. Variability in response to superovulation will also affect inbreeding rates and the average accuracy of selection. Simulation studies are needed to quantify the total effect of variability in response to superovulation on the genetic responses possible in nucleus breeding schemes relying on multiple ovulation and embryo transfer.

Analysis of Variance↗
PubMed1991

Quantification of alpha s1-casein in goat milk from French-Alpine and Anglo-Nubian breeds using reversed-phase high performance liquid chromatography.

Samples of isoelectrically precipitated goat casein from the milks of French-Alpine and Anglo-Nubian breeds were separated into four components in a single run by reversed-phase HPLC. The proportion of alpha s1-casein thus resolved was determined quantitatively. The method uses a reversed-phase C-4 column and a linear gradient from 30 to 50% acetonitrile in 30 min with trifluoroacetic acid constant at .1%. Sodium dodecyl sulfate-PAGE was carried out to establish the identity of the isolated components. By a comparison with previously published results for caprine and bovine milk caseins, the four peaks were identified as kappa-, alpha s2-, alpha s1-, and beta-casein. Quantitative variations in the chromatographically resolved alpha s1-casein fraction of goat milk were evident. Some individual goat milks contained high levels of alpha s1-casein (2.70 g/L), but others contained significantly low levels (.12 g/L). There was no statistical difference in the overall means between breeds in alpha s1-casein composition, but cluster analysis statistics showed three distinct categories of alpha s1-producers: high, medium, and low. Interestingly, 6 of 15 French-Alpine goats and only one Anglo-Nubian goat fell into the "low" producer category (.38 +/- .2 g/L). Thus, expression of the alpha s1-component may be genetically regulated but may not be a breed-specific trait.

Animals↗
PubMed1994

Optimal breeding strategies for calving ease.

Calving ease is of economic importance in dairy cattle and should be considered in breeding programs. Economic values of direct and maternal calving ease were derived based on cost-benefit analysis and gene flow methodology. Marginal returns from dystocia reduction in primiparous dams were -$43 per phenotypic standard deviation compared with $300 for production. For an average mate, numbers of discounted expressions for sires to breed replacements were .58, .44, and .63 for direct and maternal calving ease and production. Discounted expressions for direct calving ease were higher when sires were mated to primiparous versus multiparous dams. Three alternative breeding strategies were compared: 1) separate selection of sires as mates of primiparous and multiparous cows, based on their respective optimal indexes for direct and maternal calving ease, 2) selection based on the optimal index for an average mate, and 3) selection on direct calving ease only. Strategies 2 and 3 allowed for assortative mating of sires with favorable direct calving ease to primiparous females subsequent to selection. Strategy 2 resulted in maximal economic response. Optimal standardized index weights under Canadian circumstances were approximately 100:9:7 for production:direct calving ease:maternal calving ease. Inclusion of calving ease traits had a minor effect (< .5%) on selection responses and efficiency but would provide proper guidelines to producers. Greatest benefits of genetic evaluations for calving ease were obtained through assortative mating.

Animals↗
PubMed1996

Effects of dietary crude protein, breed, parity, and health status on the fertility of dairy cows.

A study was conducted to determine the impact of dietary CP (13% vs. 20%), parity (first vs. second lactation or later), and breed (Holstein vs. Jersey) on the reproductive efficiency of dairy cows. Sixty-four cows were blocked by parity and breed and assigned to one of two treatments. Cows were removed from treatments on d 100 or 120 depending on pregnancy status. Cows were categorized by health status based on the occurrence of postparturient disorders. Plasma urea N concentrations were influenced by diet (8.6 vs. 21 mg/dl, 13 and 20% CP, respectively), parity, and breed. Reproductive indices were not influenced by diet except that days to first estimated ovulation increased for cows fed the 20% CP diet when health status was added to the model. Days to first observed estrus, first AI service, and cumulative pregnancy rate were affected by health status. Regression analysis for survival showed an interaction of diet and health status for days open. High CP diets tended to increase days open when cows had major health problems; otherwise, a high CP diet decreased days open. The implementation of a strict reproductive management program allowed high reproductive efficiency goals to be achieved regardless of plasma urea N concentrations.

Animals↗
PubMed1994

Genotype by environment interactions in laying hens based on relationship between breeding values of sires in temperate and tropical environments.

This study was conducted to evaluate the significance of genotype by environment (G x E) interactions for tropical poultry breeding. Three environmental conditions were considered: controlled normal-temperature (20 +/- 2 C, CN) and controlled high-temperature (32 C, CH) housing in Germany as well as natural open tropical housing in Malaysia (22 to 34 C, TO). Eighty-four sires were considered as genotypes. Their 5,352 progeny were tested simultaneously over three environments. For each sire, its part breeding value (BV) was estimated within each environment for each performance trait. Correlations between these BV for a pair of environments were used to estimate the magnitude of G x E interactions and the degree of relationship between them to demonstrate their implications on breeding strategies. Differences between observed and expected genetic correlations of BV for body weight, egg weight, egg number, egg mass, feed intake, and production efficiency as a fraction of the expected correlation were 5.1, 4.0, 36.7, 36.5, 17.7, and 31.6%, respectively, suggesting greater significance of G x E interactions for reproduction and production efficiency. The relationships between BV over the three environments were linear for most of the traits studied, but the coefficients of determination were dependent upon the magnitude of interactions involved. Relative efficiencies of indirect selection in CN or CH for performance in TO were also very low.

Animals↗
PubMed1978

Breeding of cynomolgus monkeys through successive generations by indoor cage system.

Vital statistics on the breeding through successive generations were presented for the cynomolgus monkey colony of NIH, Tokyo. The results of this retrospective survey clearly demonstrated the third (F2) and the fourth (F3) generations could be bred and reared successfully by the indoor caged-breeding system in which either individual timed-mating or group mating procedure was adopted. Several important and difficult problems involved in the production of successive generations of the cynomolgus monkey by our breeding system were discussed from the standpoint of laboratory animal science.

Age Factors↗