Global spread of Salmonella Enteritidis via centralized sourcing and international trade of poultry breeding stocks.

A pandemic of Salmonella enterica serotype Enteritidis emerged in the 1980s due to contaminated poultry products. How Salmonella Enteritidis rapidly swept through continents remains a historical puzzle as the pathogen continues to cause outbreaks and poultry supply becomes globalized. We hypothesize that international trade of infected breeding stocks causes global spread of the pathogen. By integrating over 30,000 Salmonella Enteritidis genomes from 98 countries during 1949-2020 and international trade of live poultry from the 1980s to the late 2010s, we present multifaceted evidence that converges on a high likelihood, global scale, and extended protraction of Salmonella Enteritidis dissemination via centralized sourcing and international trade of breeding stocks. We discovered recent, genetically near-identical isolates from domestically raised poultry in North and South America. We obtained phylodynamic characteristics of global Salmonella Enteritidis populations that lend spatiotemporal support for its dispersal from centralized origins during the pandemic. We identified concordant patterns of international trade of breeding stocks and quantitatively established a driving role of the trade in the geographic dispersal of Salmonella Enteritidis, suggesting that the centralized origins were infected breeding stocks. Here we demonstrate the value of integrative and hypothesis-driven data mining in unravelling otherwise difficult-to-probe pathogen dissemination from hidden origins.

Development of sustainable performance index based on production, reproduction, health and longevity for genetic improvement of Sahiwal cattle.

An attempt was made for the first time in India to develop the performance indices for quantifying the relative emphasis to be given to production, reproduction, health and longevity traits for selection and genetic improvement of Sahiwal cattle in a sustainable manner. The study was conducted using information related to various production, reproduction, health and longevity traits spread over a period of 29 years in Sahiwal cattle. Using income and expenditure method, the relative economic values for 305 days milk yield (305DMY), average daily milk yield (ADMY), calving to first insemination interval (CFI), days open (DO) and longevity (LNG) were estimated as 1, 1, -6.62, -6.62 and 5.96 in Sahiwal cattle. A total of three performance indices were constructed using three-trait combination, that is production, reproduction and longevity before and after excluding the days suffered by the animals. Correlation between the aggregate genotype and index (RIH ) was computed to determine the accuracy of each performance index, and based on highest RIH value, best performance index was identified for selection of Sahiwal cattle. Developed indices were further assessed for robustness by increasing the relative economic values of the traits by 25% and 50%. The performance index (305DMY, DO and LNG) was found to be the best index before as well as after excluding days suffered by the animals, but in later case emphasis to be given to different traits was found to be more balanced. The best index indicated that about 47, 42 and 11% relative emphasis to be assigned to 305 days milk yield, days open and longevity for selection of Sahiwal animals for sustainable genetic improvement.

The analysis of chinchilla (Chinchilla lanigera, M.) male reproduction. The case of a leading polish breeding farm.

Research into the chinchilla male fertility concerned mainly semen quality. Little attention has been paid to lifetime reproductive performance, essential from the economical point of view. Thus, the aim of this study was to analyze factors affecting the intensity of breeding use and lifetime performance of male chinchillas. After data transformation, the analysis of variance was performed to evaluate the effect of male birth litter size and age at the first effective mating. Additionally, the correlation coefficients for both litter sizes and litter rearing efficiency were calculated. For all traits, the linear regression on the sire's age at the first effective mating was found non-significant. Litter sizes differed slightly between seasons. The length of sire reproductive use was highly correlated (about 0.8) with the total number of litters and kits born and weaned. The total rearing efficiency was low, and in some cases negatively correlated with other traits, that is, with the total number of litters and kits born and weaned. Most sires were mated up to six dams; they were used in one polygamous set each. In total, the males sired about 60 litters each, hence the conclusion is that they could be extensively used and produce more benefits to chinchilla breeders.

Assessment of reproductive and growth performance of pigs on commercial swine farms in southern Kyushu, Japan.

The objective of the present study was to assess the productivity of pigs to investigate the time-dependent change in productivity and compare productivity according to breeding company group and porcine reproductive and respiratory syndrome (PRRS) status on commercial swine farms in southern Kyushu, Japan. Data used in the present study were 245 annual productivity records from 2014 to 2018 obtained from 72 farms. Average sow inventory was 481.2 sows. Mean numbers of pigs weaned per sow per year and market pigs sold per sow per year were 23.7 and 21.6, respectively. Pigs born alive per litter increased from 11.1 to 11.9 pigs from 2014 to 2018 (p < .05). Farms using domestic breeding companies had similar numbers in 2016 to those using international breeding companies, but fewer pigs in 2014, 2015, 2017, and 2018 (p < .05). Farms with an unknown or unstable PRRS status had fewer pigs born alive per litter and pigs weaned per sow per year than those with stable or negative PRRS statuses (11.2 ± 0.06 vs. 11.8 ± 0.08 pigs and 22.6 ± 0.38 vs. 25.0 ± 0.22 pigs, respectively; p < .05). These results can be used to establish feasible targets and standards of performance to identify problem areas and improve production.

Barriers to entering race training before 4 years of age for Thoroughbred horses born in the 2014 Australian foal crop.

Currently, there is a paucity of data on the barriers for Australian Thoroughbred horses transitioning from stud farm to racetrack. This paper reports the reasons why horses failed to enter race training and documents their exit destinations. Biographical records of Australian Thoroughbred horses born in 2014 were investigated to determine the number of horses that had not officially entered race training by the start of the 4-year old racing season (1 August 2018). Of the 13,677 foals born in 2014, 66% had commenced training and 51% had raced before the beginning of their 4-year-old season in Australia. A sampling frame based on the post code of the premises where foals were born and records from Racing Australia were used to select a geographically representative sample of the 2014 Australian Thoroughbred foal crop (n = 4,124). From the population eligible for sampling 1,275 horses that had not entered training were enrolled in the survey and their breeders were sent an online questionnaire with follow-up phone calls for those who had not responded. Of the 633 responses (50% of 1275) the most frequent outcomes for horses were: death (38%, n = 239), participation in the racing industry in their 4-year old racing season (24%, n = 154) and retirement (16%, n = 100) either as Australian Stud Book (ASB) bloodstock (n = 17), or as horses rehomed outside the Thoroughbred industry (n = 83). Illness or injury was the most frequent reason for horses not entering race training that were ASB bloodstock, rehomed or deceased. There was a loss of traceability at the point of sale with most horses sold at 1 year of age. This study provides important information on the reasons, alternative outcomes and gaps in traceability for horses not entering training prior to the 4-year-old racing season.

The cherry 6+9K SNP array: a cost-effective improvement to the cherry 6K SNP array for genetic studies.

Cherry breeding and genetic studies can benefit from genome-wide genetic marker assays. Currently, a 6K SNP array enables genome scans in cherry; however, only a third of these SNPs are informative, with low coverage in many genomic regions. Adding previously detected SNPs to this array could provide a cost-efficient upgrade with increased genomic coverage across the 670 cM/352.9 Mb cherry whole genome sequence. For sweet cherry, new SNPs were chosen following a focal point strategy, grouping six to eight SNPs within 10-kb windows with an average of 0.6 cM (627 kb) between focal points. Additional SNPs were chosen to represent important regions. Sweet cherry, the fruticosa subgenome of sour cherry, and cherry organellar genomes were targeted with 6942, 2020, and 38 new SNPs, respectively. The +9K add-on provided 2128, 1091, and 70 new reliable, polymorphic SNPs for sweet cherry and the avium and the fruticosa subgenomes of sour cherry, respectively. For sweet cherry, 1241 reliable polymorphic SNPs formed 237 informative focal points, with another 2504 SNPs in-between. The +9K SNPs increased genetic resolution and genome coverage of the original cherry SNP array and will help increase understanding of the genetic control of key traits and relationships among individuals in cherry.

Estimation of genetic parameters of defective appearances in Japanese Black heifer calves in Kagoshima.

Defective appearances, including white spotting (WS), tongue defect (TD), and nipple defect (ND), in Japanese Black cattle potentially lead to economic losses to farmers in Japan. We estimated genetic parameters of defective appearances using 553,433 records of Japanese Black heifer calves housed in the Kagoshima Prefecture. Variance and covariance were estimated using the Gibbs sampling algorithm. The estimated heritability ranged from 0.29 for TD to 0.76 for WS. Percent breeding value (%BV) estimates indicated high variation in WS and ND among sires, reflecting higher heritability. Furthermore, there was a positive linear relationship between the %BV estimate of a sire and the mean incidence rate of each defect in his female offsprings. TD was positively associated with other defects. Therefore, genetic factors strongly affect the incidence of defective appearances in Japanese Black cattle.

The economic value of days open in Holstein cows in Japan based on simulated changes in conception rate.

Increasing herd-life length and culling parity with increasing conception rate (CR) is necessary to increase lifetime profit from dairy cow production. Economic values of days open (DO) were determined by calculating changes in fertility traits, herd-life length, and milk yield when the simulated CR were changed in increments of 1% from -5% to 5% from the basal levels, which were obtained for Hokkaido and regions other than Hokkaido separately. When CR increased, number of artificial inseminations, DO, and milking length decreased. Furthermore, culling parity, and annual milk yield increased. Herd-life length increased in Hokkaido and decreased in the other regions. The economic values of CR were 1,623.8 to 946.8 yen and of DO were 857.4 to 399.0 yen. Relative economic values of milk yield to days open per genetic standard deviation were higher in the other regions than in Hokkaido where the economic effect of selection for DO was expected to be equal to selection for 305-day milk yield and herd life. If the survival rate of multipara cows in the other regions increases, then the economic value of DO would similarly increase in Hokkaido.

The genetic correlation between feed conversion ratio and growth rate affects the design of a breeding program for more sustainable fish production.

BACKGROUND: Most fish breeding programs aim at improving growth rate and include feed conversion ratio (FCR) neither in the breeding goal nor in the selection index, although decreasing FCR is known to increase farm profit and decrease environmental impacts. This is because FCR is difficult to measure in fish that live in groups and FCR is assumed to have a favourable (negative) genetic correlation with growth, although the magnitude of this correlation is unknown. We investigated the effect of the genetic correlation between growth and FCR on the economic and environmental responses of a two-trait breeding goal (growth and FCR), compared to a single-trait breeding goal (growth only). Next, we evaluated the weights to assign to growth and FCR in a two-trait breeding goal to maximize sustainability of fish production. METHODS: We used pseudo-best linear unbiased prediction (BLUP) index calculations to simulate a breeding program for sea bass. For the single-trait breeding goal, the trait in the breeding goal and in the index was thermal growth coefficient (TGC) and for the two-trait breeding goal, the traits in the breeding goal were TGC and FCR and the traits in the index were TGC and percentage of fat in the dorsal muscle (an indirect measure of FCR). We simulated responses to selection for genetic and phenotypic correlations between TGC and FCR ranging from 0 to - 0.8. Then, in the two-trait breeding goal, we calculated the economic return and the change in eutrophication when using economic values (EV) or environmental values (ENV). RESULTS: When the genetic correlation between TGC and FCR was lower than - 0.45, we found major differences in economic returns and in eutrophication between single and two-trait breeding programs. At a correlation of - 0.25, the two-trait breeding goal based on EV increased economic return by 25% compared to the single-trait breeding goal, while using ENV decreased eutrophication by 1.34% per ton of fish produced after one generation of selection. CONCLUSIONS: The genetic correlation between TGC and FCR affects the magnitude of economic losses due to omitting FCR in the breeding program. In addition, the genetic correlation affects the importance of choosing EV or ENV to reduce eutrophication and increase profit.

The economic value of R0 for selective breeding against microparasitic diseases.

BACKGROUND: Microparasitic diseases are caused by bacteria and viruses. Genetic improvement of resistance to microparasitic diseases in breeding programs is desirable and should aim at reducing the basic reproduction ratio [Formula: see text]. Recently, we developed a method to derive the economic value of [Formula: see text] for macroparasitic diseases. In epidemiological models for microparasitic diseases, an animal's disease status is treated as infected or not infected, resulting in a definition of [Formula: see text] that differs from that for macroparasitic diseases. Here, we extend the method for the derivation of the economic value of [Formula: see text] to microparasitic diseases. METHODS: When [Formula: see text], the economic value of [Formula: see text] is zero because the disease is very rare. When [Formula: see text]. is higher than 1, genetic improvement of [Formula: see text] can reduce expenditures on vaccination if vaccination induces herd immunity, or it can reduce production losses due to disease. When vaccination is used to achieve herd immunity, expenditures are proportional to the critical vaccination coverage, which decreases with [Formula: see text]. The effect of [Formula: see text] on losses is considered separately for epidemic and endemic disease. Losses for epidemic diseases are proportional to the probability and size of major epidemics. Losses for endemic diseases are proportional to the infected fraction of the population at the endemic equilibrium. RESULTS: When genetic improvement reduces expenditures on vaccination, expenditures decrease with [Formula: see text] at an increasing rate. When genetic improvement reduces losses in epidemic or endemic diseases, losses decrease with [Formula: see text] at an increasing rate. Hence, in all cases, the economic value of [Formula: see text] increases as [Formula: see text] decreases towards 1. DISCUSSION: [Formula: see text] and its economic value are more informative for potential benefits of genetic improvement than heritability estimates for survival after a disease challenge. In livestock, the potential for genetic improvement is small for epidemic microparasitic diseases, where disease control measures limit possibilities for phenotyping. This is not an issue in aquaculture, where controlled challenge tests are performed in dedicated facilities. If genetic evaluations include infectivity, genetic gain in [Formula: see text] can be accelerated but this would require different testing designs. CONCLUSIONS: When [Formula: see text], its economic value is zero. The economic value of [Formula: see text] is highest at low values of [Formula: see text] and approaches zero at high values of [Formula: see text].

Symposium review: An abundance of replacement heifers: What is the economic impact of raising more than are needed?

Historically, most dairy producers raised every heifer born, to ensure a supply of future replacements. However, advancements in transition and reproductive management, coupled with widespread use of sex-sorted semen in dairy heifers and cows, have led to an oversupply of dairy replacement heifers in the United States. With current market values for prepartum heifers at $1,300 and estimated raising costs ranging from $1,700 to $2,400, dairies that continue to produce quantities of heifers in excess of anticipated needs with plans of selling the extras on the open market are likely to experience significant economic loss. Adult cow herd turnover is the key driver behind the number of heifers needed to calve; however, mortality, disease, fertility, and elective culling losses throughout the heifer-raising period determine the total number of heifers that must be retained and raised to meet anticipated needs. A convenience sample of 50 US dairy herds revealed an average heifer inventory of 102% of total milking and dry cows. In this data set, the mean annualized adult herd turnover was 39%. With a mean stillbirth risk of 5.7% in calving heifers, a culling risk of 10.2% by 13 mo of age, a reproductive failure risk of 6.8% in breeding heifers, and an additional culling risk of 6.4% in pregnant heifers, only 74% of calving events with a heifer birth yielded a heifer that entered the lactating herd. Much of this heifer removal was elective, and making the correct culling decisions at the appropriate time yields the best return for the herd. To demonstrate how a herd might approach the elective culling issue, a records-based exercise with 2 large Holstein herds was performed to estimate the cost versus benefit of 3 different elective culling approaches, using a combination of genetic potential and growth performance as the selective criteria. However, the culling of heifers results in economic losses, because the revenue received is less than the cost incurred during raising. Selective culling of heifers soon after weaning yielded the best results in both herds, but despite the predicted improvement in lactation performance of the retained group, the cost associated with removal was greater than the benefit predicted. Culling a group early and then culling a second group just before calving yielded the largest loss. Moving forward, herds should breed more carefully to produce better-quality heifers from more superior dams and sires and consider the use of beef semen in inferior animals. However, to reduce the risk of not producing an adequate supply of replacement heifers, dairies should add an additional buffer to their anticipated needs. Using the assumptions within this project, having 10% extra calving events with a heifer birth would allow the annualized adult herd turnover to rise from 39 to 43% in case economic conditions or health status of the herd should change. If these heifers are not needed, the selection criteria outline could be used to help identify more valuable animals to retain.

Estimation of economic weights for number of teats and sperm quality traits in pigs.

Accurate predictive modelling facilitates efficient and effective trait selection in animal breeding and can decrease costs while maximizing profits when raising economically important animals. The objective of this study was to extend a previously developed bioeconomic model and computer program to calculate the marginal economic values (MEVs) and economic weights (EWs) for direct and maternal pig traits affected by new reproductive traits, namely the number of sow functional teats (NFTs) and boar sperm quality traits (SQTs) that included sperm volume, sperm concentration, motility percentage and percentage of abnormal spermatozoa. The MEV of NFTs represented the cost differences between naturally and artificially reared piglets until weaning and the cost differences between naturally and artificially reared finished animals. The MEVs of SQTs expressed the saved costs for artificial insemination, assuming a decreased price per insemination dose when improving the SQTs. The absolute and relative EWs for the newly defined complex of traits in the breeding objectives for pig breeds involved in the Czech national three-way crossing system (Czech Large White [CLW], Czech Landrace [CL] and Pietrain [PN]) were calculated using gene flow methods. The NFT trait was included only for dam breeds, and the relative EW averaged 3.6% of the total economic importance based on the genetic standard deviations of all 19 simultaneously evaluated traits in CLW and CL breeds. The relative EWs of the four SQTs comprised 2.0% of the total economic importance of the 19 traits in the CLW and CL dam breeds and 8% of the total economic importance of the 18 traits in the PN sire breed. Therefore, inclusion of the NFTs for dam breeds and SQTs for sire breeds in the breeding goal is recommended to aid in obtaining ideal outcomes with optimal economic values.

Breeding objectives of Brangus cattle in Brazil.

Our goal was to define a breeding objective for Brangus beef cattle in Brazil. Bioeconomic models were produced and used to estimate economic values (EVs). The scenarios simulated were typical full-cycle beef production systems that are used in tropical and subtropical regions. The breeding objective contained pregnancy rate (PR), warm carcass weight (WCW), mature cow weight (MCW), number of nematode eggs per gram of faeces (EPG) and tick count (TICK). Two models were used in series to estimate the EV. A deterministic model was used to simulate effects of PR, WCW and MCW on profitability with a constant parasite load. Subsequently, stochastic models were used to estimate economic values for TICK and EPG as consequences of their environmental effects on weight gains, mortality and health costs. The EV of PR, WCW, MCW, EPG and TICK, was US$1.59, US$2.11, -US$0.24, -US$5.35 and -US$20.88, respectively. Results indicate positive emphasis should be placed on PR (12.49%) and WCW (65.07%) with negative emphasis on MCW (13.92%), EPG (2.77%) and TICK (5.75%). In comparison with the indexes usually used, these results suggest a reformulation in the selection indexes of the beef production system in tropical and subtropical regions in order to obtain greater profitability.

Application of embryo biopsy and sex determination via polymerase chain reaction in a commercial equine embryo transfer program in Argentina.

Embryo biopsy for fetal sexing has clinical application, but few reports are available of its use within an active embryo transfer program. We evaluated results on biopsy of 459 embryos over one breeding season. There were no significant differences in pregnancy rate between biopsied and non-biopsied embryos (72% vs 73%) or for biopsied embryos recovered at the centre (73%) compared with those shipped overnight (72%). However, the pregnancy rate decreased significantly in shipped embryos biopsied ≥20h after collection. Overall, 86% of biopsies provided a sex diagnosis. The likelihood of a positive genomic (g) DNA result was significantly higher for biopsies from large blastocysts (96%) than from smaller embryos (70-85%). In total, 38% of biopsies were positive for Y chromosome DNA (Y-DNA) and were diagnosed as male. Subsequently, 95% of Y-DNA-positive embryos were confirmed as male and 78% of Y-DNA-negative embryos were confirmed as female. The accuracy of prediction of female (Y-DNA negative) was significantly higher when the biopsy sample was probed for Y-DNA only compared with probing for both gDNA and Y-DNA. We estimate that by transferring only Y-DNA-negative embryos, 3% of potential female pregnancies may have been lost, and production of male pregnancies was reduced by 72%.

Mare and stallion effects on blastocyst production in a commercial equine ovum pick-up-intracytoplasmic sperm injection program.

This study retrospectively examined the degree to which success within a commercial ovum pick-up (OPU)-intracytoplasmic sperm injection (ICSI) program varied between individual mares and stallions. Over 2 years, 552 OPU sessions were performed on 323 privately owned warmblood mares. For mares that yielded at least one blastocyst during the first OPU-ICSI cycle, there was a 77% likelihood of success during subsequent attempts; conversely, when the first cycle yielded no blastocyst, the likelihood of failure (no embryo) in subsequent cycles was 62%. In mares subjected to four or more OPU sessions, the mean percentage of blastocysts per injected oocyte was 20.5% (range 1.4-46.7%), whereas the mean number of blastocysts per OPU-ICSI session was 1.67 (0.2-4.2). Age did not differ significantly between mares that yielded good or poor results. The number of recovered oocytes per OPU was positively associated with the likelihood of success (P<0.001). Although there were considerable between-stallion differences, most stallions (14/16) clustered between 15.6% and 26.8% blastocysts per injected oocyte, and the number of blastocysts per OPU (mean 1.4; range 0.2-2.2) was less variable than among mares. In conclusion, although both mare and stallion affect the success of OPU-ICSI, mare identity and the number of oocytes recovered appear to be the most reliable predictors of success.

A breeding index to rank beef bulls for use on dairy females to maximize profit.

The desire to increase profit on dairy farms necessitates consideration of the revenue attainable from the sale of surplus calves for meat production. However, the generation of calves that are expected to excel in efficiency of growth and carcass merit must not be achieved to the detriment of the dairy female and her ability to calve and re-establish pregnancy early postcalving without any compromise in milk production. Given the relatively high heritability of many traits associated with calving performance and carcass merit, and the tendency for many of these traits to be moderately to strongly antagonistic, a breeding index that encompasses both calving performance and meat production could be a useful tool to fill the void in supporting decisions on bull selection. The objective of the present study was to derive a dairy-beef index (DBI) framework to rank beef bulls for use on dairy females with the aim of striking a balance between the efficiency of valuable meat growth in the calf and the subsequent performance of the dam. Traits considered for inclusion in this DBI were (1) direct calving difficulty; (2) direct gestation length; (3) calf mortality; (4) feed intake; (5) carcass merit reflected by carcass weight, conformation, and fat and the ability to achieve minimum standards for each; (6) docility; and (7) whether the calf was polled. Each trait was weighted by its respective economic weight, most of which were derived from the analyses of available phenotypic data, supplemented with some assumptions on costs and prices. The genetic merit for a range of performance metrics of 3,835 artificial insemination beef bulls from 14 breeds ranked on this proposed DBI was compared with an index comprising only direct calving difficulty and gestation length (the 2 generally most important characteristics of dairy farmers when selecting beef bulls). Within the Angus breed (i.e., the beef breed most commonly used on dairy females), the correlation between the DBI and the index of genetic merit for direct calving difficulty plus gestation length was 0.74; the mean of the within-breed correlations across all other breeds was 0.87. The ranking of breeds changed considerably when ranked based on the top 20 artificial insemination bulls excelling in the DBI versus excelling in the index of calving difficulty and gestation length. Dairy breeds ranked highest on the index of calving difficulty and gestation length, whereas the Holstein and Friesian breeds were intermediate on the DBI; the Jersey breed was one of the poorest breeds on DBI, superior only to the Charolais breed. The results clearly demonstrate that superior carcass and growth performance can be achieved with the appropriate selection of beef bulls for use on dairy females with only a very modest increase in collateral effect on cow performance (i.e., 2-3% greater dystocia expected and a 6-d-longer gestation length).

Economic optimization of full-sib test group size and genotyping effort in a breeding program for Atlantic salmon.

BACKGROUND: Breeding companies may want to maximize the rate of genetic gain from their breeding program within a limited budget. In salmon breeding programs, full-sibs of selection candidates are subjected to performance tests for traits that cannot be recorded on selection candidates. While marginal gains in the aggregate genotype from phenotyping and genotyping more full-sibs per candidate decrease, costs increase linearly, which suggests that there is an optimum in the allocation of the budget among these activities. Here, we studied how allocation of the fixed budget to numbers of phenotyped and genotyped test individuals in performance tests can be optimized. METHODS: Gain in the aggregate genotype was a function of the numbers of full-sibs of selection candidates that were (1) phenotyped in a challenge test for sea lice resistance (2) phenotyped in a slaughter test (3) genotyped in the challenge test, and (4) genotyped in the slaughter test. Each of these activities was subject to budget constraints. Using a grid search, we optimized allocation of the budget among activities to maximize gain in the aggregate genotype. We performed sensitivity analyses on the maximum gain in the aggregate genotype and on the relative allocation of the budget among activities at the optimum. RESULTS: Maximum gain in the aggregate genotype was €386/ton per generation. The response surface for gain in the aggregate genotype was rather flat around the optimum, but it curved strongly near the extremes. Maximum gain was sensitive to the size of the budget and the relative emphasis on breeding goal traits, but less sensitive to the accuracy of genomic prediction and costs of phenotyping and genotyping. The relative allocation of budget among activities at the optimum was sensitive to costs of phenotyping and genotyping and the relative emphasis on breeding goal traits, but was less sensitive to the accuracy of genomic prediction and the size of the budget. CONCLUSIONS: There is an optimum allocation of budget to the numbers of full-sibs of selection candidates that are phenotyped and genotyped in performance tests that maximizes gain in the aggregate genotype. Although potential gains from optimizing group sizes and genotyping effort may be small, they come at no extra cost.

Use of sexed semen and female genotyping affects genetic and economic outcomes of Montbéliarde dairy herds depending on the farming system considered.

Genomic evaluation of cows and the use of sexed semen have recently provided opportunities for commercial dairy farmers to accelerate genetic progress at the herd level by increasing both selection accuracy and selection intensity. Because implementing genomic tests or using sexed semen generate extra costs, a higher investment capacity of the farm is required. In this study, we compared the effect of female genotyping alone or combined with the use of sexed semen on genetic and economic performance of the herds. Three typical Montbéliarde herds with different farming systems were considered: a 77-cow herd producing milk at a high price sold to make cheese with a protected designation of origin, a 60-cow herd producing organic milk at a medium price sold for dairy, and a 120-cow herd producing standard milk at a lower price sold for dairy. Eight alternative scenarios were simulated over a 10-yr period for each herd, with combinations of the following: use (or not) of dairy sexed semen, use (or not) of beef breed semen, use (or not) of female genotyping at 15 d of age. A mechanistic, stochastic, and dynamic model was used to mimic the farmer's daily decisions and the individual cow's biology. Heifers (80%) and first-lactation cows (30%) that ranked highest on the French total merit index (France's national dairy index) were inseminated with sexed semen to ensure replacement and to maximize genetic gain, when sexed semen was used. During the 10 yr of simulation, scenarios that included sexed semen (whether female genotyping was used or not) gained, on average, one extra year of overall genetic gain over scenarios that did not include sexed semen. During the same period, scenarios that used female genotyping (whether sexed semen was used or not) gained, on average, 5 mo of overall genetic gain over scenarios using parent average only. The highest gains in net margin were always obtained when combining use of sexed semen with terminal crossbreeding. Maximum genotyping prices under which routine female genotyping is economically valuable (breakeven prices of genotyping) were under €37. Maximum genotyping prices, such that the female genotyping costs are refunded within 10 yr of investment (investor genotyping price), were under €26. However, they would be higher over a longer period of use because genetic gain is cumulative. Because genotyping price is expected to decrease in the future, female genotyping will be worthwhile if combined with the use of sexed semen and beef breed semen.

Intake, efficiency, and feeding behavior characteristics of Holstein-Friesian cows of divergent Economic Breeding Index evaluated under contrasting pasture-based feeding treatments.

The objective of the current study was to explore differences in dry matter intake, intake capacity, production efficiency, energy balance, and grazing behavior, of 2 divergent genetic groups (GG) of lactating Holstein-Friesian, selected using the Irish Economic Breeding Index (EBI). The GG were evaluated across 3 spring calving pasture-based feeding treatments (FT) over 3 yr. The 2 divergent GG were (1) high EBI, representative of the top 5% nationally (elite), and (2) EBI representative of the national average (NA). In each year 90 elite and 45 NA cows were randomly allocated to 1 of 3 FT: control, lower grass allowance, and high concentrate. Although FT did affect animal performance, there were few notable incidences of GG × FT interaction. The elite cows expressed lower daily milk yield (-1 kg) compared with NA. Elite cows did, however, express higher daily concentrations of milk fat (+3.7 g/kg) and protein (+2.1 g/kg) compared with NA. Daily yield of milk solids and net energy of lactation (NEL) was similar for both GG. Body weight (BW) was greater for NA (+13 kg) compared with elite, whereas mean body condition score was greater (+0.14) for elite compared with NA. Intake did not differ significantly between GG. Intake capacity, expressed as total dry matter intake/100 kg of BW, was greater with elite compared with NA. Production efficiency expressed as yield of milk solids per 100 kg of BW was greater with elite compared with NA, although milk solids/total dry matter intake did not differ between GG. Expressed as NEL as a proportion of net energy intake minus net energy of maintenance (NEL/NEI - NEM) and NEI/milk solids kg, indicated a slight reduction in the utilization of ingested energy for milk production with elite compared with NA. This is, however, suggested as favorable as it manifested as a more positive energy balance with elite compared with NA and so is likely to enhance robustness, increase longevity, and increase overall lifetime efficiency. Noteworthy was a consistent numerical trend toward more intense grazing activity with elite compared with NA cows, exhibited in the numerically greater grazing time (+19 min) and total number of bites per day (+2,591).