Relationship between dairy cow genetic merit and profit on commercial spring calving dairy farms

peer-reviewedBecause not all animal factors influencing profitability can be included in total merit breeding indices for profitability, the association between animal total merit index and true profitability, taking cognisance of all factors associated with costs and revenues, is generally not known. One method to estimate such associations is at the herd level, associating herd average genetic merit with herd profitability. The objective of this study was to primarily relate herd average genetic merit for a range of traits, including the Irish total merit index, with indicators of performance, including profitability, using correlation and multiple regression analyses. Physical, genetic and financial performance data from 1131 Irish seasonal calving pasture-based dairy farms were available following edits; data on some herds were available for more than 1 year of the 3-year study period (2007 to 2009). Herd average economic breeding index (EBI) was associated with reduced herd average phenotypic milk yield but with greater milk composition, resulting in higher milk prices. Moderate positive correlations (0.26 to 0.61) existed between genetic merit for an individual trait and average herd performance for that trait (e.g. genetic merit for milk yield and average per cow milk yield). Following adjustment for year, stocking rate, herd size and quantity of purchased feed in the multiple regression analysis, average herd EBI was positively and linearly associated with net margin per cow and per litre as well as gross revenue output per cow and per litre. The change in net margin per cow per unit change in the total merit index was h1.94 (s.e.50.42), which was not different from the expectation of h2. This study, based on a large data set of commercial herds with accurate information on profitability and genetic merit, confirms that, after accounting for confounding factors, the change in herd profitability per unit change in herd genetic merit for the total merit index is within expectations

Carcass characteristics of cattle differing in Jersey proportion

peer-reviewedComparison of alternative dairy (cross-)breeding programs requires full appraisals of all revenues and costs, including beef merit. Few studies exist on carcass characteristics of crossbred dairy progeny originating from dairy herds as well as their dams. The objective of the present study was to quantify, using a national database, the carcass characteristics of young animals and cows differing in their fraction of Jersey. The data set consisted of 117,593 young animals and 42,799 cows. The associations between a combination of sire and dam breed proportion (just animal breed proportion when the dependent variable was on cows) with age at slaughter (just for young animals), carcass weight, conformation, fat score, price per kilogram, and total carcass value were estimated using mixed models that accounted for covariances among herdmates of the same sex slaughtered in close proximity in time; we also accounted for age at slaughter in young animals (which was substituted with carcass weight and carcass fat score when the dependent variable was age at slaughter), animal sex, parity of the cow or dam (where relevant), and temporal effects represented by a year-by-month 2-way interaction. For young animals, the heaviest of the dairy carcasses were from the mating of a Holstein-Friesian dam and a Holstein-Friesian sire (323.34 kg), whereas the lightest carcasses were from the mating of a purebred Jersey dam to a purebred Jersey sire which were 46.31 kg lighter (standard error of the difference = 1.21 kg). The young animal carcass weight of an F1 Holstein-Friesian × Jersey cross was 20.4 to 27.0 kg less than that of a purebred Holstein-Friesian animal. The carcass conformation of a Holstein-Friesian young animal was 26% superior to that of a purebred Jersey, translating to a difference of 0.78 conformation units on a scale of 1 to 15. Purebred Holstein-Friesians produced carcasses with less fat than their purebred Jersey counterparts. The difference in carcass price per kilogram among the alternative sire-dam breed combinations investigated was minimal, although large differences existed among the different breed types for overall carcass value; the carcass value of a Holstein-Friesian animal was 20% greater than that of a Jersey animal. Purebred Jersey animals required, on average, 21 d longer to reach a given carcass weight and fat score relative to a purebred Holstein-Friesian. The difference in age at slaughter between a purebred Holstein-Friesian animal and the mating between a Holstein-Friesian sire with a Jersey dam, and vice versa, was between 7.0 and 8.9 d. A 75.8-kg difference in carcass weight existed between the carcass of a purebred Jersey cow and that of a Holstein-Friesian cow; a 50% Holstein–Friesian-50% Jersey cow had a carcass 42.0 kg lighter than that of a purebred Holstein-Friesian cow. Carcass conformation was superior in purebred Holstein-Friesian compared with purebred Jersey cows. Results from this study represent useful input parameters to populate simulation models of alternative breeding programs on dairy farms, and to help beef farmers evaluate the cost-benefit of rearing, for slaughter, animals differing in Jersey fraction.This publication arose from research supported in part by a research grant from Science Foundation Ireland (Dublin) and the Department of Agriculture, Food and Marine on behalf of the Government of Ireland under the Grant 16/RC/3835 (VistaMilk; Dublin, Ireland) as well as funding from the Research Stimulus Fund (BreedQuality and GREENBREED; Dublin, Ireland) and Meat Technology Ireland (MTI; Dublin, Ireland), a co-funded industry/Enterprise Ireland project (TC 2016 002)

Promoter and Riboswitch Control of the Mg2+ Transporter MgtA from Salmonella enterica

The MgtA protein from Salmonella enterica serovar Typhimurium mediates Mg(2+) uptake from the periplasm into the cytoplasm. Here we report that the PhoP/PhoQ two-component regulatory system, which responds to periplasmic Mg(2+), governs mgtA transcription initiation at all investigated Mg(2+) concentrations and that the Mg(2+)-sensing 5′ leader region of the mgtA gene controls transcription elongation into the mgtA coding region when Salmonella is grown in media with <50 μM Mg(2+). Overexpression of the Mg(2+) transporter CorA, which is believed to increase cytoplasmic Mg(2+) levels, decreased mgtA transcription in a manner dependent on a functional mgtA 5′ leader

Accuracy of predicting milk yield from alternative milk recording schemes

peer-reviewedThe effect of reducing the frequency of official milk recording and the number of recorded samples per test-day on the accuracy of predicting daily yield and cumulative 305-day yield was investigated. A control data set consisting of 58 210 primiparous cows with milk test-day records every 4 weeks was used to investigate the influence of reduced milk recording frequencies. The accuracy of prediction of daily yield with one milk sample per test-day was investigated using 41 874 testday records from 683 cows. Results show that five or more test-day records taken at 8-weekly intervals (A8) predicted 305-day yield with a high level of accuracy. Correlations between 305-day yield predicted from 4-weekly recording intervals (A4) and from 8-weekly intervals were 0.99, 0.98 and 0.98 for milk, fat and protein, respectively. The mean error in estimating 305-day yield from the A8 scheme was 6.8 kg (s.d. 191 kg) for milk yield, 0.3 kg (s.d. 10 kg) for fat yield, and −0.3 kg (s.d. 7 kg) for protein yield, compared with the A4 scheme. Milk yield and composition taken during either morning (AM) or evening (PM) milking predicted 24-h yield with a high degree of accuracy. Alternating between AM and PM sampling every 4 weeks predicted 305-day yield with a higher degree of accuracy than either all AM or all PM sampling. Alternate AM-PM recording every 4 weeks and AM + PM recording every 8 weeks produced very similar accuracies in predicting 305-day yield compared with the official AM + PM recording every 4 weeks

Strategija europskog uzgoja goveda Fleckvieh za optimiziranje uzgoja dvostruke namjene osobito za proizvodnju govedine

Želimo li da Simentalac/Fleckvieh ostane pasmina dvostruke namjene morat će se nastaviti istodobno poboljšavati mesne i mliječne osobine. Nastojanje da se odobre i zatim održavaju dvije alternativne uzgojne strategije unutar jedne pasmine povezano je s poteškoćama. Možda će biti teško raditi unutar rodoslovnika u smislu postizanja sporazuma a zatim kako se rodoslovnik održava. Da li će biti potrebne dvije sekcije u rodoslovniku i ako je tako gdje će se bilježiti živo¬tinje, te rezultati parenja među odabranim mliječnim i mesnim značaj¬kama? Ovo se pitanje pojavilo u Irskoj. Problem je riješen pitanjem kako najbolje poslužiti potrebama mesne industrije. Tako se došlo do prepoznavanja niza osobina te na toj osnovi do pokazatelja što mogu poslužiti komercijalnim uzgajivačima goveda, bili oni u proizvodnji mlijeka ili mesa. Osnovan je, zatim, sustav genetske procjene za identi¬ficiranje uzgojne vrijednosti svih životinja za različite pokazatelje. Uzgajivači i farmeri slobodno donose odluke o ekonomskom uzgoju, naj¬boljem za njihove određene potrebe. U Irskoj, na primjer, očekuje se da će se razviti određeni stupanj specijalizacije kao rezultat stva¬ranja ovih pokazatelja u vezi s općim trendovima u industriji nakon parenja. Neki se proizvođači mogu specijalizirati za proizvodnju zamjenskih uzgojnih ženka na temelju na osnovi majčinskih pokazatelja, dok će se drugi uzgajivači za priplod koncentrirati na proizvodnju rasplodnih bikova za upotrebu u proizvodnji govedine, gdje će biti važna samo lakoća izravnog telenja uz indekse proizvodnje govedine. Uvođenje dvaju uzgojnih ciljeva za jednu pasminu može konačno dati samo dvije izrazite pod-pasmine

Validation of national genetic evaluations for maternal beef cattle traits using Irish field data

peer-reviewedGenetic evaluations provide information to aid in breeding decisions that increase long-term performance of animals and herds. However, to date no study has been undertaken to investigate the accuracy of the Irish maternal genetic evaluations in beef cattle. The objective, therefore, of this study was to quantify the relationship between phenotypic performance and measures of genetic merit for predominantly maternal-related traits in Irish beef cattle. The association between animal EBV for calving interval, age at first calving, and both direct and maternal weaning weight with the respective phenotypic performance was quantified using a fixed effects model; the expectation for the regression coefficient of phenotypic performance on EBV was one. The association between genetic merit for cow survival, perinatal mortality, calving assistance, and calving dystocia with the log of the odds of the respective trait was quantified using logistic regression. The association analyses were conducted using field data on up to 38,619 records from 5,236 herds. Age at first calving increased linearly by 0.32 ± 0.15 (P = 0.03) days per day increase in EBV for age at first calving. Calving interval increased by, on average, 0.58 ± 0.16 (P = 0.002) days per day increase in EBV for calving interval although the association differed by parity with a greater association in pluriparae. Weaning weight increased linearly by 1.74 ± 0.09 and 0.84 ± 0.16 kg (P < 0.001) per kilogram increase in EBV for direct and maternal weaning weight, respectively. The log of the odds of a cow surviving to next lactation increased linearly by 0.16 ± 0.03 (P < 0.001) per unit increase in EBV for cow survival. The log of the odds of an assisted calving or dystocia both increased linearly by 0.21 ± 0.01 and 0.24 ± 0.01, respectively, per unit increase in EBV for direct calving difficulty (P < 0.001). The log of the odds of a dead calf at birth increased linearly by 0.93 ± 0.13 (P < 0.001) per unit increase in EBV for calf mortality. Results from this study show that selection of breeding animals for favorable maternal genetic attributes will result in favorable improvements in performance and profitability

Work-related musculoskeletal disorders : A survey of physical therapists in Izmir-Turkey

BACKGROUND: This study was planned to collect data about causes, prevalence and responses to work-related musculoskeletal disorders reported by physiotherapists employed in Izmir, Turkey. METHOD: A two-page survey with closed ended questions was used as the data collected method. This survey was distributed to 205 physiotherapists working in Izmir, Turkey, and 120 physiotherapists answered. Questions included occupational history of physiotherapists and musculoskeletal symptoms, special areas, tasks, job-related risk factors, injury prevention strategies, and responses to injury. RESULTS: Eighty-five percent of the physiotherapists have had a musculoskeletal injury once or more in their lifetime. Injuries have been occurred mostly in low back (26 %), hand-wrist (18 %), shoulders (14 %) and neck (12 %). The highest risk factor in causing the injury was transferring the patient at 15%. Sixty-nine percent of physiotherapists visited a physician for their injury and sixty-seven percent of the respondents indicated that they had not limited their patient contact time as a result to their injury CONCLUSIONS: According to the results of this study, the rate of musculoskeletal disorders in physiotherapists in Izmir-Turkey has been found to be high due to their profession. Respondents felt that a change in work habits was required in order to decrease the risk of another injury

Branching out: meiotic recombination and its regulation

Homologous recombination is a dynamic process by which DNA sequences and strands are exchanged. In meiosis, the reciprocal DNA recombination events called crossovers are central to the generation of genetic diversity in gametes and are required for homolog segregation in most organisms. Recent studies have shed light on how meiotic crossovers and other recombination products form, how their position and number are regulated and how the DNA molecules undergoing recombination are chosen. These studies indicate that the long-dominant, unifying model of recombination proposed by Szostak et al. applies, with modification, only to a subset of recombination events. Instead, crossover formation and its control involve multiple pathways, with considerable variation among model organisms. These observations force us to &apos;branch out&apos; in our thinking about meiotic recombination

Investigating the use of visible and near infrared spectroscopy to predict sensory and texture attributes of beef M. longissimus thoracis et lumborum

peer-reviewedThe aim of this study was to calibrate chemometric models to predict beef M. longissimus thoracis et lumborum (LTL) sensory and textural values using visible-near infrared (VISNIR) spectroscopy. Spectra were collected on the cut surface of LTL steaks both on-line and off-line. Cooked LTL steaks were analysed by a trained beef sensory panel as well as undergoing WBSF analysis. The best coefficients of determination of cross validation (R2CV) in the current study were for textural traits (WBSF = 0.22; stringiness = 0.22; crumbly texture = 0.41: all 3 models calibrated using 48 h post-mortem spectra), and some sensory flavour traits (fatty mouthfeel = 0.23; fatty after-effect = 0.28: both calibrated using 49 h post-mortem spectra). The results of this experiment indicate that VISNIR spectroscopy has potential to predict a range of sensory traits (particularly textural traits) with an acceptable level of accuracy at specific post-mortem times.This work is funded by the BreedQuality project (11/SF/311) which is supported by The Irish Department of Agriculture, Food and the Marine (DAFM) under the National Development Plan 2007–2013

Fertility of fresh and frozen sex-sorted semen in dairy cows and heifers in seasonal-calving pasture-based herds

peer-reviewedOur objective in this study was to evaluate the reproductive performance of dairy heifers and cows inseminated with fresh or frozen sex-sorted semen (SS) in seasonal-calving pasture-based dairy herds. Ejaculates of 10 Holstein-Friesian bulls were split and processed to provide (1) fresh conventional semen at 3 × 106 sperm per straw (CONV); (2) fresh SS at 1 × 106 sperm per straw (SS-1M); (3) fresh SS semen at 2 × 106 sperm per straw (SS-2M); and (4) frozen SS at 2 × 106 sperm per straw (SS-FRZ). Generalized linear mixed models were used to evaluate the effect of semen treatment and other explanatory variables on pregnancy per artificial insemination (P/AI) in heifers (n = 3,214) and lactating cows (n = 5,457). In heifers, P/AI was greater for inseminations with CONV (60.9%) than with SS-FRZ (52.8%) but did not differ from SS-1M (54.2%) or SS-2M (53.5%). Cows inseminated with CONV had greater P/AI (48.0%) than cows inseminated with SS, irrespective of treatment (SS-1M, SS-2M, and S-FROZEN; 37.6, 38.9, and 40.6%, respectively). None of the SS treatments differed from each other with regard to P/AI in either heifers or cows. The relative performance of SS compared with CONV was also examined [i.e., relative P/AI = (SS P/AI)/(CONV P/AI) × 100]. Frozen SS achieved relative P/AI >84%. Bull affected P/AI in both heifers and cows, but no bull by semen treatment interaction was observed. In heifers, P/AI increased with increasing Predicted Transmitting Ability for milk protein percentage. In cows, P/AI increased with increasing Economic Breeding Index (EBI) and with days in milk (DIM) at AI but decreased with increasing EBI milk subindex, parity and with DIM2. Cows in parity ≥5 had the lowest P/AI and differed from cows in parities 1, 2, or 3. Dispatch-to-AI interval of fresh semen did not affect P/AI in lactating cows, but a dispatch-to-AI interval by bull interaction was detected whereby P/AI was constant for most bulls but increased with greater dispatch-to-AI intervals for 2 bulls. In conclusion, frozen SS achieved greater P/AI relative to conventional semen than was previously reported in lactating cows. Fresh SS did not achieve greater P/AI than frozen SS, regardless of whether the sperm dose per straw was 1 × 106 or 2 × 106. A bull effect for all semen treatments, as well as a dispatch-to-AI interval by bull interaction for fresh semen, highlights the importance of using a large team of bulls for breeding management