The performance of early-maturing breed sired suckler bulls finished at pasture, with or without concentrate supplementation, at 15 or 19 months of age was evaluated. In total, 60 Aberdeen Angus-sired bulls were assigned to a two (slaughter age (SA): 15 (S15) or 19 (S19) months)×two (finishing strategies (FS): grass only or grass+barley-based concentrate) factorial arrangement. There were no (P>0.05) SA×FS interactions. Increasing SA increased carcass weight (265 v. 355 kg), kill-out proportion (542 v. 561 g/kg), conformation (6.7 v. 8.3, 1 to 15) (P<0.001) and fat (5.8 v. 6.8) scores (P<0.01), and resulted in yellower subcutaneous fat (‘b’ value, 6.6 v. 8.3) and darker muscle (‘L’ value, 30.0 v. 28.3) (P<0.01). Supplementation reduced estimated herbage intake by 0.60 and 0.47 kg dry matter (DM)/kg DM of concentrates for S15 and S19, respectively. Supplementation increased carcass weight (+6.7%, P<0.001) and kill-out proportion (+1.8%, P=0.06) but had no effect on carcass fat and conformation scores or fat and muscle colour. In conclusion, carcasses were adequately finished, with or without concentrates for S19, but not for S15. Supplementation had no effect, and age had relatively minor effects, on fat and muscle colour.

This experiment aimed to assess the effect of different indoor winter growth rates (WGR) followed by different concentrate supplementation levels at pasture on meat quality of 90 bulls. During the first winter, bulls were offered grass silage ad libitum and either 3 kg (WGR3) or 6 kg (WGR6) of concentrates. After turn-out to pasture, bulls were offered: grass without supplementation (PO), grass plus 0.2 predicted dry matter intake (DMI) as concentrates (PL) or grass plus 0.4 predicted DMI as concentrates (PH). After finishing, colour, chemical composition (unaged), instrumental texture and sensory characteristics (14 days of ageing) of longissimus thoracis were measured. WGR6 bulls had heavier carcasses than WGR3 bulls. There was an interaction between WGR and supplementation for instrumental texture and redness (a). Within WGR3, PO beef was the most tender, whereas within WRG6, PL was the most tender. However, these differences were not detected by the sensory panel. Within WGR3, redness was the lowest for PL, whereas within WRG6, PO was the least red. No differences were found for chemical composition. The multivariate analysis highlighted WGR as the main variable affecting meat quality characteristics. In conclusion, variations in growth path exerted minor effects on appearance and instrumental texture which did not affect the perception of bull beef by a trained sensory panel.

In cattle, the chemical composition of the carcass is usually evaluated from one of three reference methods (rib dissection, specific gravity or a combination of easily obtained measures) or is estimated from proxy traits (USDA yield grade (YG), subcutaneous fat thickness (SFT)). Objectives were to evaluate if the relationships between the chemical composition of the carcass and each of the proxy traits (YG, SFT) differed depending on the reference method. The study was conducted by meta-analysis from published results using 25 publications that reported carcass composition and proxy traits (53%, 31% and 16% of the data were based on rib dissection, specific gravity and combination of easily obtained measures, respectively). Results showed that the amounts of carcass fat or protein that can be predicted from a given proxy trait (YG or SFT) differ significantly with the reference method used to determine carcass fat or protein.

Intramuscular connective tissue plays an important role in meat tenderness. Our objective was to compare the collagen/hydroxyproline content and X-ray computed tomographic (CT) connective tissue proportion of longissimus thoracis (LT) muscle in Hungarian Simmental bulls and cows. Cows had lower carcass weight (247 kg v. 295 kg), EU conformation score (3.5 v. 5.5) and fatness score (4.2 v. 5.9) than bulls (P<0.01). Bulls had higher LT area, but intramuscular fat content was similar for bulls and cows. On the other hand, bulls had lower CT intramuscular connective tissue proportion in LT compared with cows (0.41±0.21% v. 0.66±0.28%, P<0.01). The same tendency could be observed for the collagen content (0.50±0.21% v. 0.67±0.11%, P<0.01). Correlation between the CT connective tissue proportion of LT and collagen content was r=0.8. There was a weak positive correlation between slaughter age and CT connective tissue as well as collagen content of LT (r=0.3 to 0.4). In conclusion, intramuscular connective tissue proportion in LT increased with slaughter age and older cows had higher collagen and connective tissue proportion than bulls. Mixed CT scans can be used for the analysis of intramuscular connective tissue content.

This study aimed to determine estimates of production efficiency among primiparous suckler cows of diverse genetic merit (GM) for the national Irish maternal index. Data from 82 heifers of diverse GM across two different replacement strategies (suckler (S) or dairy (D) sourced) were available. Milk yield, grass dry matter intake, cow BW and body condition score (BCS) were recorded. The maternal index had no significant effect on any parameters investigated, whereas S cows were 86 kg heavier in BW, had a 0.33 greater BCS and 0.6 UFL greater NEM requirement compared with D beef crossbred (F1) cows. The F1 produced 2.2 kg/day more milk and had greater lactation energy requirements (0.8 UFL) than S. The F1 produced 0.48 kg milk per 100 kg BW and 0.15 kg more milk per unit intake. An interaction between GM and cow origin (CO) showed that F1 low merit cows consumed an additional 1 kg DM than F1 high, and that S high merit cows produced 1.5 kg less milk than their S low counterparts resulting in a 0.5 UFL greater energy requirement for milk production for S low. The F1 high merit cows produced 0.12 kg more milk per unit intake than F1 low cows, whereas S low cows produced 0.12 kg less milk per unit intake than S high. The F1 low cows consumed 0.17 kg more DM per unit BW than F1 high. Thus, genetic selection for maternal traits has not resulted in differences in production efficiency traits, however CO differences were observed.

The aim of this study was to identify genomic regions that associated with beef tenderness in Nellore cattle. Phenotypes were obtained according to the standard USDA Quality Grade (1999). Data from 909 genotyped Nellore bulls were used in the Genome-Wide Association Study (GWAS) undertaken using a single-step approach including also a pedigree file composed of 6276 animals. The analyses were performed using the Blupf90 software, estimating the effect of genomic windows of 10 consecutive markers. The GWAS results identified 18 genomic regions located on 14 different chromosomes (1, 4, 6, 7, 8, 10, 18, 19, 20, 21, 22, 25, 26 and 29), which explained more than 1% of the total additive genetic variance; several candidate genes were located in these regions including SLC2A9, FRAS1, ANXA3, FAM219A, DNAI, AVEN, SHISA7, UBE2S, CDC42EP5, CNTN3, C16orf96, UBALD1, MGRN1 and SNORA1 With the single-step GWAS, it was possible to identify regions and genes related to meat tenderness in Nellore beef cattle.

Inversing the STICS crop model with remote-sensing-derived leaf area index (LAI) and yield data from the previous crop is used to retrieve some soil permanent properties and crop emergence parameters. Spatialized nitrogen (N) fertilization recommendations are provided to farmers, for the second and third N applications, following the screening of eleven N application rates under a range of possible forthcoming climates, with the objective to maximize of the gross margin while respecting some environmental constraints. As a first field validation, we show (1) the improvement brought by the assimilation of LAI and yield into STICS to simulate crop and soil variables and (2) the interest of site specific application to maximize both the gross margin and the agro-environmental criterion.

There is growing interest in monitoring soil biological health to complement the traditional evaluation of soil physical and chemical characteristics in agricultural fields. Activity of soil microorganisms mediates many essential soil processes that affect fertility, and, therefore, essential to the successful adoption of precision agriculture. However, there are technical limitations to cost-effective monitoring of spatial and temporal dynamics of soil biological activity across agricultural landscapes. This paper summarizes three consecutive studies on in situ measurement of soil biological activity. The first study reveals spatial heterogeneity of microbial population growth in three agricultural fields using bio-films. In the second study, microbiological activity was analyzed using a substrate-induced respiration technique. This technique was evaluated through a series of soil toxicity experiments that involved a comparison of fresh and autoclaved soil samples. Finally, the aim of the third study was to develop a portable instrumented system to evaluate carbon dioxide concentrations in soil by extracting air stored within the soil pores. This instrument was tested under various conditions to quantify the effects of soil moisture, compaction and presence of glucose (artificially increased microbial respiration). Optimization of the discussed techniques will allow for detailed mapping of these indices of soil biological health and their interactions with the physical and chemical environment at any specific point in time.

The objective of this work was to determine the most appropriate growth stage to make reflectance measurements that would indicate yield in high yielding winter barley crops. The results indicated that where different rates of fertiliser N were applied, at the same crop growth stages, the best relationship between vegetation indices, calculated on the basis of reflectance measurements, and grain yield were found to occur from booting to early grain fill. Where the timing of fertiliser N inputs was different, for a given level of fertiliser N addition, poor correlations between vegetation indices and grain yield during the stem elongation phase were observed.

By providing high spatial resolution images of vine fields througout the vine growing season, UAVs could provide useful information, different than those normally considered in the literature. This study aimed at identifying i) relevant information that can be observed from UAV images by two kind of stakeholders : growers and advisers (G&A) ii) the most suitable periods for this observation iii) and the added value this information can have for both G&A daily tasks. This approach has been conducted on an 11.3 ha commercial vineyard representative of the south of France vineyards. UAV-based visible images (2.5 cm resolution) have been acquired in commercial conditions every two weeks from budburst to harvest. Images have been presented to two groups of G&A six times during the growing season. Every expert gathering was conducted with i) an individual period where images were presented to each expert ii) a collective period where G&As were invited to share information. Application of this methodology demonstrated that much information about the vines, the soil and the vineyard environment can be extracted from UAV-based visible images without any image processing. Results showed that this information have added value all along the growing cycle of the vine, particularly for advisers.

This paper presents an inspection system integrated into an on-ground autonomous platform with range of approximately 80 km. The vehicle is prepared to autonomously cover a field following a predefined route plan. Two types of cameras were integrated in the platform. An RGB-D sensor and a reflex camera were placed in a fixture and connected to a high-performance computer. The heterogeneous information acquired from the RGB-D was later integrated to automatically generate 3D maps of the crops by using custom software developed in the authors’ previous work. The inspection system performance was tested in actual vineyards by conducting several samplings in 2016. Results show that the proposed technology is viable and can provide complementary information to other inspection alternatives.

A ‘chessboard’ field experiment set up to investigate how the yield response to nitrogen (N) fertiliser varied spatially within a field in the UK indicated that the optimum N rate varied substantially by up to 100 kg N/ha within the three hectare experimental area. Variation in N optima was negatively related to the soil N supply. However, soil N supply, yield potential and apparent fertiliser recovery rate were inter-related which meant that the influence of each element on N optima was complex. Spectral reflectance indices related well to crop N uptake and could be used to help estimate soil N supply.

The University of Georgia (USA) is partnering with the University of Padova (Italy) for a dual Master’s degree program in sustainable agriculture, promoting collaboration on some of the biggest challenges facing agriculture today. This innovative program which was launched during 2016 provides students with outstanding training and a unique opportunity to learn about the challenges, opportunities, and leading edges of precision agriculture on another continent – an experience which will serve graduates well when they enter the job market in an increasingly global economy. This paper presents the goals of the program, the curriculum, and describes the opportunities available to prospective students. In addition it describes the process of developing the dual degree which can be used as guide by others wishing to develop similar programs.