Grass-based Production Systems Research Articles

Sustainable intensification of grass-based beef production systems in alpine regions: How to increase economic efficiency while preserving biodiversity?

CONTEXTBeef production on grasslands has multiple positive impacts. In addition to the production of high-quality protein, marginal lands in particular enable high biodiversity and landscape quality. However, this type of production is perceived as less economical than more intensive meat production systems. OBJECTIVEThe aim of the study is to develop recommendations on how different grass-based production systems can be economically improved without endangering biodiversity. METHODSThirty-five suckler cow farms supplying into two different brand programmes (Natura-Veal: slaughter age at five months; Natura-Beef: slaughter age at 10 months) were grouped into four production systems across two production sites in Switzerland: Natura-Veal, mountain region, extensive (VMount); Natura-Beef, mountain region (BMount); Natura-Veal, hilly region, intensive (VHill) and Natura-Beef, lowlands (BLowla). On the farms, beef production was analysed in detail on the basis of technical production data as well as full cost accounting. The farms were grouped into one model farm (farm type) per production system. On each model farm, optimisation options were simulated and checked for practicability with farmer participation. The optimisation focused primarily on improving cow efficiency via the sale of more slaughter animals per cow, through lower animal losses, higher fertility or the additional purchase of calves suckled by a nurse cow. RESULTS AND CONCLUSIONSDescriptive statistics showed significant positive correlations between stocking rate and land productivity and significant negative correlations between stocking rate/land productivity and the share of biodiversity areas (SBA), confirming previous findings. These relationships were also reflected in the production site of the farms, as mountain farms with lower productivity had a significantly higher SBA, while farms in areas with better grass growth had fewer biodiversity areas but higher productivity. Accordingly, the optimisation options were adapted to the production site under the constraint of a constant stocking rate. In favourable forage-growing areas, further intensification via improving cow efficiency by buying foreign calves led to significant improvements in profitability (VHill and BLowla). In mountain areas, the optimisation potential is lower. Site-adapted, i.e., small-framed and robust, cow types lead to better cow efficiency, which also contributes to good profitability in extensive production with a high biodiversity share, although this is strongly determined by national direct payments (VMount and BMount). Both income and biodiversity can be optimised if cow efficiency is increased and production systems are adapted to the site as closely as possible. SIGNIFICANCEThe study shows practicable recommendations for sustainable intensification in grass-based meat production systems in the current discussion on maintaining or increasing biodiversity in agriculture.

Combined mechanistic and genetic modelling to benchmark body reserve traits as proxies of dairy cows’ lifetime efficiency in grass-based production systems

Improving lifetime lactation efficiency of dairy cows by selection is difficult due to the complexity of this trait and the existence of genotype-by-environment interactions. This study aimed at assessing the relevance of traits derived from body reserves as lifetime efficiency indicators under contrasting nutritional environments. Given the absence of large-scale datasets covering a panel of feeding regimes, phenotypes were simulated for populations of 20 000 dairy cows using a mechanistic bioenergetic model. Ten phenotypes were computed for third-lactation cows. Analysed phenotypes comprised total milk production, lactation efficiency, BW at calving (BWcalv), DM intake (DMI) and interval between first insemination and conception. Five traits described levels and changes of body reserves at different periods during lactation. Lifetime lactation efficiency was computed for all cows (Life_Eff). Three nutritional environments were defined considering a grass-based production system with seasonal calving: a high non-limiting scenario (HS) mimicking ad libitum access to feed and two limiting environments with moderate (MS) and low (LS) feed offer. Variance components were estimated for all traits within and between environments using REML. Heritabilities estimated for milk production, lactation efficiency, BWcalv and DMI were moderate in the different environments (0.27–0.35 ± 0.04). The heritability of body reserve levels and dynamics were moderate in the HS and MS scenarios (0.23–0.30 ± 0.03) and lower in the LS scenario (0.14–0.25 ± 0.03). The heritability of Life_Eff was low in the HS environment (0.07 ± 0.01) and slightly increased in the limiting environments. All genetic correlations estimated between environments were moderate to high (≥0.66 ± 0.07), suggesting low to moderate genotype-by-environment interactions. Estimated genetic correlations were moderate between Life_Eff and body reserve levels (from 0.39 to 0.51 ± 0.08) and moderate but negative between Life_Eff and change in body reserves traits (−0.27 to −0.37 ± 0.09) in the HS environment. The genetic correlations between Life_Eff and body reserve levels increased to higher values in the limiting environments. In contrast, genetic correlations between Life_Eff and the changes in body reserves were closer to zero. In conclusion, this study showed that body reserve levels were relevant proxies of lifetime irrespective of the environment. In contrast, changes in body reserves that reflected energy mobilisation in early lactation were less informative about lifetime efficiency in environments with severe feed restrictions.

PSXII-9 Application of Machine Learning Algorithms to Estimate Tropical Pasture Biomass Based on Satellite Images

Abstract The proper quantification of forage allowance for ruminants in grass-based production systems has always been challenging. At the field scale, pasture management based on ground-level measurements, such as clipping or plate meter, is labor intensive and hampers the assessment of spatial and temporal variability. On the lookout for a solution, this study aimed to estimate marandu palisade grass forage mass based on satellite images using two machine learning (ML) algorithms, Multiple Linear Regression (MLR) and Artificial Neural Network (ANN). The experimental area comprised Marandu palisade grass pasture (Brachiaria brizantha ‘Marandu’), summing 33 paddocks (42 ha), receiving or not N fertilization. Pastures were managed under continuous stocking to maintain grazing height fixed at 25 cm during the growing season, using the put-and-take methodology with young beef bulls. Field dataset collection (total forage mass and morphological composition) and satellite images were assessed from Dec/2015 to Mar/2019 during the growing or wet season. The satellite images (Landsat-8 and Sentinel-2) were downloaded from US Geological Survey (USGS, http://earthexplorer.usgs.gov). Six spectral bands (Bd) and five vegetation indices (VI, Table 1) were used as input variables to MLR and ANN models. Datasets were randomly divided into a training set (80%) and a testing set (20%). Analyses were run in Python 3 (version 3.7). ML models are generally data-driven and require a large amount of data for better performance, and the best accuracy was achieved by using all Bd and VIs as input variables for both models (Table 1). In general, ANN produced better estimates than MLR models. Bd+VI better predicted leaf mass than total forage mass. Our results show that remotely sensed observations, based on satellite images, are a promising and effective tool for tropical grassland monitoring and management under continuous stocking rates. São Paulo Research Foundation (FAPESP) (grant ≠15/16631-5; 17/18750-7; 20/14367-7).

Influence of different feeding strategies on carcass and meat quality of grassfed cull cows

Animal performance, carcass and meat quality characteristics of beef cull cows under different feeding strategies were evaluated. Cows were allotted to one of four direct grazing treatments combining different levels of forage allowance (FA) and supplementation rate (% of live body weight, BW) using rice bran (RB): T1= FA2%+RB0, T2= FA4%+RB0, T3= FA2%+RB0.8% and T4= FA2%+RB1.6%. Cows from T1 presented lower (P<0.05) slaughter weight (SW) than the other three treatments. Additionally, T1 presented lower weight (P<0.05) for rump and loin, striploin, sirloin, inside round and tri-tip, compared to T2, T3 and T4. Intramuscular fat (IMF), pH (48 h), Warner-Bratzler shear force (WBSF; aged for 7 or 21 days), lean colour, saturated fatty acid (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) concentrations did not differ among treatments (P>0.05). A strategic use of low RB supplementation rate grazing on an oats forage crop, improves both carcass and meat qualitry traits of cull cows, adding value and promoting healthy meat production for human consumption from grass-based production systems.

Morphological and physiological measures as predictors of age at puberty and conception in beef heifer genotypes

This study examined the utility of postweaning morphological and physiological measures as predictors of age of puberty and conception in beef heifers. Data were used from 309 spring-born heifer progeny [initial age 231 d (SD = 16); BW 256 kg (SD = 52)] of beef and dairy dams sired by early-maturing (EM) or late-maturing (LM) breeds and bred (12 wk) to calve at 24 mo of age within a grass-based production system. Body weight, composition and linear measurements, blood metabolites, pubertal age, and pregnancy were determined. Mean ages at puberty and conception were 429 d (range = 275–496 d) and 458 d (range = 398–534 d), respectively. Pubertal age was strongly correlated with age at first AI (r = 0.68) and conception (r = 0.48). Body weight deposition from 8 to 13 mo of age was negatively associated with age at puberty (r = −0.33), first AI (r = −0.17), and conception (r = −0.12). Pubertal age was negatively associated with BW at 10 and 13 mo (r = −0.15 to −0.19), ultrasonic measures of fatness from 10 to 15 mo of age (r = −0.15 to −0.30), IGF-1 concentrations from 8 to 13 mo (r = −0.22 to −0.31), and insulin (r = −0.22 to −0.24) and leptin (r = −0.18 to −0.21) concentrations at 10 and 13 mo. Prediction equations developed using multiple regression explained 25% of the variation in pubertal age for EM heifers [IGF-1 concentrations at 8 mo (15%), leptin (4%) and glucose (3%) concentrations at 10 mo, and BW at 13 mo (3%)] and 30% for LM heifers [IGF-1 (18%) and glucose (5%) concentrations at 8 mo and insulin concentrations (4%) and lumbar fat thickness (3%) at 13 mo]. In relatively well-grown replacement beef heifers, BW was a weak predictor of pubertal status. Physiological measures, particularly IGF-1 concentrations at 8 mo of age, were superior.

Characteristics of robust animals for grass-based production systems

A characterisation of dairy, beef and sheep breeds and/or strains best suited to profitable/sustainable production within the context of European [semi] intensive pasture-based systems is presented. To deliver optimal performance, pasture must be managed effectively, but pasture-based systems are less energy intensive, are climate sensitive and induce challenges and constraints not normally posed to animals in intensive feeding environments. This emphasises the importance of animal traits associated with robustness and adaptive abilities. A survey of French dairy farmers concluded that a robust cow is an “invisible” cow with a long lifetime. The traits common to both indoor and grazing systems include: efficient converters of feed to human edible products, functionality, being healthy, reproductively fit and exhibiting longevity. Unique to successful grazing is the capability to achieve large intakes of forage to meet productive potential, an ability to adapt to fluctuating feed supply and, in seasonal systems, the ability to conceive and give birth at the appropriate time each year, usually within 365 d. The breed or strain of choice may differ based on local management constraints and objectives; however, general principles apply, and ideally should be guided by a suitable selection index combining all of the economically important traits appropriate to the local conditions and systems.

Growth, efficiency and the fatty acid composition of blood and muscle from previously grazed late-maturing bulls fed rumen protected fish oil in a high concentrate finishing ration

In bulls, with a genetic predisposition for leanness and reared in a grass-based production system dietary fish oil may further enhance the nutritional value of beef by increasing the concentration of the omega 3 polyunsaturated fatty acids (PUFA) eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). The impact of including rumen protected fish oil in the finishing diet of late maturing breed bulls on their growth, feed efficiency, carcass fat classification, aspects of ultimate meat quality and the fatty acid composition of the M. Longissimus thoracis muscle (LT) was examined. Twelve month old bulls were supplemented with a barley-based concentrate (500g/kg dietary dry matter) from turn-out to pasture in spring until housing 94 days later. Bulls were housed indoors and offered ad libitum, either the same concentrate or a concentrate containing rumen protected fish oil (PFO) at a ration fat concentration of 50g/kg dry matter, along with grass silage to appetite, for 88 days pre-slaughter. Inclusion of PFO increased (P<0.05) concentrate consumption, but this was not reflected in carcass growth, classification or fat colour or in LT colour or tenderness. Concentrations of 18:2, EPA, DHA, total PUFA and the PUFA: saturated fatty acid ratio (0.19 v 0.14) were higher (P<0.05) in LT from PFO compared to control bulls. The increase in EPA + DHA, associated with PFO inclusion, from 7 to 12 mg/100g muscle is below the concentration required by European Commission regulations (40 mg/100g) to allow this beef to be labelled a “source of” EPA + DHA. Nevertheless, consuming beef from PFO bulls would make a greater contribution to the daily consumer requirement for omega-3 PUFA than beef from the control bulls. This has potential to add value to beef from the PFO production system.

Grazing of Dairy Cows in Europe—An In-Depth Analysis Based on the Perception of Grassland Experts

Grazing is inherently close to the nature of herbivores, but no longer applied everywhere in Europe. Therefore, the perception of grassland experts on the occurrence, importance, constraints, solutions and future of grazing of dairy cows was studied. The study builds on results from the European Grassland Federation Working Group Grazing in the period 2010–2019. Both surveys and focus group meetings were used. There is a clear trend of reduced grazing in Europe. Since grazing is valued by different stakeholders and provides many ecosystem services, solutions to the constraints to grazing must be found. Constraints can be divided into region specific constraints, farm specific constraints and farmer specific constraints. The solutions include developing new knowledge, bringing the knowledge already available to practice and rewarding farmers for grazing as a service to society. If grazing is not supported, it will further decline. However, a joined endeavour has the potential to make a significant difference in transforming grass-based production systems and stimulating grazing.

Finishing strategies for cull cows under grass-based production systems in Uruguay

Finishing strategies for cull cows under grass-based production systems in Uruguay

The effects of cereal type and α-tocopherol level on milk production, milk composition, rumen fermentation, and nitrogen excretion of spring-calving dairy cows in late lactation

Grass-based production systems use concentrate supplementation primarily when pasture quality and availability have declined. Barley is a common concentrate ingredient; however, oat grain grows well in Ireland, is a source of lipids and fiber, and may provide an alternative to barley. The antioxidant α-tocopherol (α-TOC) plays a role in cell membrane structure, and it has the potential to improve tight junction structures of the mammary gland that deteriorate in late lactation. The objective of this research was to investigate the effect of cereal type and α-TOC level on milk yield, milk composition, rumen fermentation, and N excretion in late-lactation dairy cows at pasture and when housed indoors on grass silage. Forty-eight Holstein Friesian dairy cows were blocked on days in milk (+185 d in milk) and balanced for parity, pre-experimental milk yield, milk composition, and body condition score and assigned to 1 of 4 dietary treatments in a randomized complete block design (n = 12). The dietary treatments were control (C) base diet; base diet + barley-based concentrate + low α-TOC (350 IU/kg) (B); base diet + oat-based concentrate + low α-TOC (350 IU/kg) (O); and base diet + oat-based concentrate + high α-TOC (1,050 IU/kg) (O+T). Following a 14-d acclimation period, diets were offered for a 49-d experimental period at pasture (P1) and a 21-d experimental period indoors (P2). The base diet was grazed grass in P1 and grass silage in P2. In P2, cows on C also received 2.65 kg (dry matter) of a standard concentrate. In P1, supplementation increased milk and milk solids yield (B: 20.7 kg/d, 1.74 kg/d; O: 20.6 kg/d, 1.81 kg/d; O+T: 20.5 kg/d, 1.77 kg/d, respectively) compared with C (17.8 kg/d, 1.60 kg/d). Cows offered B had a lower milk fat (4.60%) concentration than C (5.00%) and O (4.90%). In P2, cereal type and α-TOC level did not alter milk production. In conclusion, concentrate supplementation increased milk and milk solids yield and cows offered O had a higher milk fat concentration than cows offered B. Increasing the level of α-TOC had no major effect on production parameters measured in P1 or in P2.

Is TB Testing Associated With Increased Blood Interferon-Gamma Levels?

The Republic of Ireland reports a relatively low prevalence of Johne’s disease (JD) compared to international counterparts. Postulated reasons for this include a lower average herd size and a grass-based production system. Ireland also engages in high levels of bovine tuberculosis (bTB) testing. As interferon-gamma (IFN-γ) is believed to play a key role in protecting against JD, it is our hypothesis that administration of purified protein derivative (PPD), as part of the bTB test, is associated with a systemic increase in IFN-γ production, which may potentially limit clinical progression of the disease. We studied 265 cows (202 Friesian and 63 “Non-Friesian,” e.g., JerseyX, Norwegian Red) to assess IFN-γ levels and Mycobacterium avium subspecies paratuberculosis (MAP) antibody response before and after the bTB test. As part of the compulsory annual bTB test, avian and bovine PPD were administered at two separate cervical sites. To assess IFN-γ production, blood samples were taken before and 72 h after PPD administration. MAP antibody response was assessed before and 10 days post-PPD administration. A significant increase in MAP antibody response was identified post-bTB compared to pre-bTB response (p < 0.001). Additionally, IFN-γ production significantly increased at the post-bTB time point (p < 0.001) compared to the pre-bTB test readings. This may indicate a beneficial effect of bTB testing in controlling JD.

The carbon balance of temperate grasslands part II: The impact of pasture renewal via direct drilling

Pasture renewal (or pasture renovation) is a common management practice in grass-based production systems aimed at restoring pasture production and forage quality. It is important to understand the impact of pasture renewal on soil organic carbon stocks.Here we report the CO2 and C balance of three blocks of an intensively managed temperate grassland in New Zealand. Two blocks underwent pasture renewal using the spray and direct drill approach (no ploughing), while the third block served as an undisturbed Control. Net ecosystem production (NEP) was measured using eddy covariance, and additional in- and outputs of C (e.g. C in pasture removed by grazers and returned in dung) either measured or estimated.NEPs of the renewed blocks were between 149 and 212gCm−2 y−1 lower than the NEP of the Control block during the year of pasture renewal. While CO2 sink strength was obviously diminished as a result of pasture renewal, neither renewed block was a source for CO2, presumably due the relatively warm climate which enabled year-round growing conditions.Despite the non-negative NEPs during the year of pasture renewal, both renewed sites were found to lose soil C as indicated by the negative net ecosystem carbon balances (NECBs). NECBs of the renewed blocks were −156 and −222gCm−2y−1, compared to a near-neutral NECB of the Control block.Comparison of the findings from the current study on pasture renewal without ploughing to those from an earlier study on pasture renewal including ploughing led to the following conclusions: i) our data did not suggest lower rates of respiratory CO2 losses when spray-and-direct-drill approach was used instead of ploughing; ii) as both the direct CO2 losses due to microbial degradation and the decrease in CO2 uptake through photosynthesis contribute to the total impact of pasture renewal on NEP, the duration of fallow period was found to be important in determining the short-term CO2 losses due to pasture renewal, with shorter fallow period leading to lower net CO2 losses; iii) addition of C in the form of manure, effluent, or extra supplemental feed for cattle may help to reduce the negative impact of pasture renewal on soil C loss at the renewed site.

Detection of anthelmintic resistance on two Irish beef research farms

Beef and milk production systems in Ireland are largely dependent on a grass-based diet with cattle spending long periods of the year at pasture (Drennan and McGee 2009). As a...

Lameness and foot lesions in Swiss dairy cows: I. Prevalence

Prevalences of foot lesions and lameness were recorded in 1'449 Swiss dairy cows during routine claw-trimming on 78 farms from June 2010 until February 2011. Lameness was present in 14.8 % of cows and on 80.8 % of investigated farms. Highest prevalences were seen for widened white line (80.7 %/100 %), signalling foot lesion (65.6 %/98.7 %), heel-horn erosion (34.2 %/88.5 %), digital dermatitis complex (29.1 %/73.1 %), severe hemorrhages (27.9 %/87.2 %), and Rusterholz' sole ulcers (11.5 %/74.4 %) at cow and herd level, respectively. Lower prevalences were found for subclinical laminitis (5.4 %/47.4 %), chronic laminitis (3.3 %/25.6 %), white line disease (4.7 %/42.3 %), double soles (2.6 %/33.3 %), interdigital hyperplasia (3.1 %/33.3 %), sole ulcers (0.4 %/6.4 %), toe infections caused by faulty claw-trimming (3.9 %/39.7 %) and by injury (0.1 %/2.6 %), deep lacerations (0.4 %/6.4 %), and interdigital phlegmona (0.1 %/1.3 %). Lameness and foot lesions were shown to represent important health problems of dairy cows under the conditions of the typical grass-based production system in Switzerland. Digital dermatitis has developed to the most relevant foot disease with a high impact on welfare of Swiss dairy cows within the past 10 years.

The effect of stocking rate and calving date on milk production of Holstein–Friesian dairy cows

The objective of this study was to evaluate the effect of stocking rate (SR) and calving date (CD) on milk production, BW and BCS within grass-based production systems post-European Union milk quotas using modern grazing management practices and high genetic potential Holstein–Friesian (HF) spring calving dairy cattle over a two year period. Two groups of HF dairy cows with different mean CD were established from within the existing research herd at Moorepark (Teagasc, Ireland). Animals were assigned either to an early calving (mean CD: 12 February) treatment or a late calving (mean CD: 25 February) treatment. Animals within each CD treatment were randomly allocated to 1 of 3 SR treatments, Low (2.51 cows/hectare (ha), Medium (2.92cows/ha) and High (3.28cows/ha) which were designed to represent 3 alternative whole farm SR in a post-European Union milk quota, spring calving, grass-based milk production system. A total of 138 spring-calving dairy cows, comprised of two strains of HF (North American HF and New Zealand HF genetic strains), were used during 2009 and 2010, respectively. The effects of CD, SR treatment, genetic strain and their interactions on milk production per cow and per ha, body weight and body condition score were analyzed. Although reducing per animal production, increased SR resulted in increased milk and milk solids production per ha. The results also indicate that although CD had no effect on total lactation performance, adjusting mean CD may be an effective strategy to align animal requirements and grass supply and reduce the requirement for supplements at increased SR in early lactation.

The effect of grazing season length on nitrogen utilization efficiency and nitrogen balance in spring-calving dairy production systems

SUMMARYThere is a continual requirement for grass-based production systems to optimize economic and environmental sustainability through increased efficiency in the use of all inputs, especially nitrogen (N). An N balance model was used to assess N use efficiency and N surplus, and to predict N losses from grass-based dairy production systems differing in the length of the grazing season (GS). Data from a 3-year grazing study with a 3×3 factorial design, with three turnout dates (1 February, 21 February and 15 March) and three housing dates (25 October, 10 November and 25 November) were used to generate estimates of N use efficiency and N losses. As the length of the GS increased by a mean of 30 days, milk production, milk solids production and milk N output increased by 3, 6 and 6%, respectively. The increase in milk production as the length of the GS increased resulted in a 2% decline in N surplus and a 5% increase in N use efficiency. Increasing GS length increased the proportion of grazed grass in the diet, which increased N cycling within the system, resulting in an 8% increase in milk solids/ha produced/kg of surplus N. The increased cycling of N reduced the quantity of N partitioned for loss to the environment by 8%. Reducing fertilizer N input by 20% increased N use efficiency by 22% and reduced total N losses by 16%. The environmental and production consequences of increased length of the GS and reduced N loss are favourable as the costs associated with N inputs increase.

Development and application of an economic ranking index for perennial ryegrass cultivars

Economic values in euros (€) were calculated for traits of economic importance in Irish grass-based systems. The economically important traits selected were spring, midseason, and autumn grass dry matter (DM) yield (€/kg of DM per ha), grass quality (€ per unit DM digestibility), first- and second-cut silage DM yield (€/kg per ha), and sward persistency (€/% change in persistency per ha per yr). The economic value for each trait was calculated by changing the trait of interest while keeping all other traits constant, using the Moorepark Dairy Systems Model. Herd parameters (including cow numbers and calving pattern), milk production, energy demand, supplementary feeds, and land area were readjusted to calculate the economic value for the trait of interest. The base scenario assumed fixed cow numbers with 40ha of land available, with full costs included. The results for the base scenario show the economic values were: €0.15/kg of DM spring yield, €0.03/kg of midseason yield, €0.10/kg of DM autumn yield, the quality value was €0.001, €0.008, €0.010, €0.009, €0.008, and €0.006 per unit change in DM digestibility/kg of DM yield for the months of April, May, June, July, August, and September, respectively; €0.036/kg of DM first-cut silage; €0.024/kg of DM second-cut silage; and -€4.961 per 1% decrease in persistency/ha per yr. Sensitivity of the economic values to changes in milk price and scenario were tested. The economic values were applied to experimental production data collected over 3 yr for 20 perennial ryegrass cultivars to establish the total economic merit for each cultivar and then to rank each cultivar based on its economic performance. Rank correlations between the base and alternative scenarios ranged from 0.90 to unity. This indicates that the economic values are reliable regardless of system, intensity, or price. The total merit index will identify the cultivars that can make the greatest economic contribution to a grass-based production system.

Quality of retail beef from two grass-based production systems in comparison with conventional beef

Seventy beef strip loins ( Longissimus dorsi) were sampled, originating from labels prescribing pasturing (PS, suckler beef; PF, finished steers or heifers), from conventional production (CH, heifers; CB, young bulls), and from a label producing intensively fattened young bulls (LB) and prescribing specific husbandry conditions but not grazing. Samples were purchased in autumn and spring (1:1) from 33 retail stores in northeastern Switzerland. Colour was lightest in LB beef, while PS displayed the least intensive red. Shear force was low in pasture beef, with PF showing the lowest variability. Pasture beef was richer in n−3 fatty acids than beef of all other origins. The n−6/ n−3 ratio was consistently below 2 in pasture beef, while it ranged above 5 in LB, and also in CH and CB when purchased in spring. Prescribing year-round feeding of grass products and the use of steers or heifers therefore guarantees n−3 enriched beef, which can be at least as tender as conventional beef.

Calving Interval and Survival Breeding Values as Measure of Cow Fertility in a Pasture-Based Production System with Seasonal Calving

In a grass-based production system with seasonal calving, fertility is of major economic importance. A delay in conception due to poor fertility prolongs intercalving interval and causes a shift in calving pattern, which can lead to culling. Calving interval (CIV) information is readily available from milk records; analyzing it, however, presents a problem, as it is only available for cows that conceive and calve again. Calving interval should therefore be treated as a censored trait. In this study, survival to the next lactation (SUV) was analyzed jointly with CIV in a multivariate linear model to account for the selection in CIV data. Genetic parameters for first lactation calving interval were estimated with a sire model for Holstein Friesian cows in Ireland. SUV was preadjusted for production within herd-year-season (HYS), while milk yield was included as a third trait in the analysis to account for the large effect it has on both traits. The residual covariance between CIV and SUV was fixed as 3 times the sire covariance within the model, as it was inestimable because of the structure of the data. Breeding values were estimated with various models to test the effect of culling and milk yield.Heritability was 0.04±0.006 for CIV and 0.01±0.003 for SUV, while the genetic correlation between them was –0.28 (±0.11). The genetic standard deviation was around 4% for SUV and 7 d for CIV. Sire predicted transmitting abilities for progeny tested bulls ranged between –5 and 3% for survival rate and between –4 and 8 d for calving interval. Differences between the best and worst bull varied with model. Including SUV and milk yield as traits in the model reduced the mean and variance of sire predicted transmitting abilities but increased the coefficient of variation by 30% compared with the univariate model. The current model is expected to account for most of the genetic variation in fertility that is possible from calving dates and future extensions, such as the use of linear type trait or additional lactations for predicting survival, appear straightforward. These traits now form part of the national index for selecting dairy bulls in Ireland.

Is it feasible to use ovum pick up and embryo transfer to produce 3 bull calves per donor and maintain annual calving cycles?

The objective of this study was to evaluate the effect of stocking rate (SR) and calving date (CD) on milk production, BW and BCS within grass-based production systems post-European Union milk quotas using modern grazing management practices and high genetic potential Holstein–Friesian (HF) spring calving dairy cattle over a two year period. Two groups of HF dairy cows with different mean CD were established from within the existing research herd at Moorepark (Teagasc, Ireland). Animals were assigned either to an early calving (mean CD: 12 February) treatment or a late calving (mean CD: 25 February) treatment. Animals within each CD treatment were randomly allocated to 1 of 3 SR treatments, Low (2.51 cows/hectare (ha), Medium (2.92 cows/ha) and High (3.28 cows/ha) which were designed to represent 3 alternative whole farm SR in a post-European Union milk quota, spring calving, grass-based milk production system. A total of 138 spring-calving dairy cows, comprised of two strains of HF (North American HF and New Zealand HF genetic strains), were used during 2009 and 2010, respectively. The effects of CD, SR treatment, genetic strain and their interactions on milk production per cow and per ha, body weight and body condition score were analyzed. Although reducing per animal production, increased SR resulted in increased milk and milk solids production per ha. The results also indicate that although CD had no effect on total lactation performance, adjusting mean CD may be an effective strategy to align animal requirements and grass supply and reduce the requirement for supplements at increased SR in early lactation.