Monitoring feeding time in ruminants is one means to quantify feed intake. In grazing cattle offered feed supplement blocks, time spent licking can provide valuable information in estimating the level of blocks being ingested. This current study aimed to 1) assess an ear-tag accelerometer's capability to identify the licking behaviour at supplement blocks in grazing cattle and 2) evaluate the performance of the ear-tag accelerometer and radio-frequency identification (RFID) system to predict the individual time spent licking. Two breed groups of Angus (n = 7) and Brahman (n = 7) beef heifers were kept in two separate yards over 28 days. Each heifer was fitted with an ear-tag containing a tri-axial accelerometer set at 12.5 Hz frequency. Feed supplement blocks were provided through an RFID-equipped automatic supplement weighing unit within each yard, with access to the unit being given daily only from 16:00 h - 20:00 h. The accelerometer classification model developed using support vector machine (SVM) algorithm could distinguish between licking and non-licking behaviours, with an accuracy, sensitivity, F1 score, Cohen's kappa coefficient, and Matthew's correlation coefficient (MCC) of 86%, 93%, 0.88, 0.70, and 0.77 for Angus and 87%, 93%, 0.89, 0.73, and 0.79 for Brahman heifers. Time spent licking predicted by accelerometers were acceptable with a mean absolute error (MAE) of 22% and 11%, modelling efficiency (MEF) of 0.81 and 0.94, concordance correlation coefficient (CCC) of 0.88 and 0.96, and a ratio of root mean square prediction error (RSR) of 0.44 and 0.25, for Angus and Brahman heifers, respectively. However, the RFID system derived predictions of time spent licking in grazing heifers were unacceptable for both breeds. Overall, the ear-tag accelerometer offers the potential to predict individual time spent licking in grazing cattle to estimate block supplement intake.

Feeding reduced protein diets may influence the microbial fermentation in the ceca due to the differences in the diet composition and nutrient digestibility compared to the standard protein diets. Two experiments were conducted to investigate the effects of L-arginine (Arg) and L-citrulline (Cit) supplementations in reduced protein diets on cecal fermentation products including ammonia and fatty acids in broilers raised under standard, cyclic warm temperature (WT), and necrotic enteritis (NE) challenge conditions. Sub-objectives were to examine preserving methods for cecal digesta (snap freezing using liquid nitrogen vs ice) and analytical methods (enzymatic assay vs Berthelot method) to determine cecal ammonia. In experiment 1, Ross 308 cockerels (n = 720) were randomly allocated to four dietary treatments with 12 replicates of 15 birds per pen from d 7 to 21. The treatments were: a standard protein diet (SP), a reduced protein diet with 2.5 percentage points lower crude protein (CP) and deficient in Arg (RP), and RP supplemented with 0.28% Arg (RP-Arg) or 0.28% Cit (RP-Cit). A factorial arrangement of treatments was applied during the finisher phase (21 to 35 d). Factors were: diet (four diets above); and temperature, NT (24°C) or cyclic WT (33°C ± 1°C for 6 h per day) using 6 replicate pens per diet per temperature. In experiment 2, Ross 308 cockerels (n = 720) were randomly assigned to six experimental treatments with eight replicates of 15 birds per pen. The treatments were: a standard protein without NE challenge (SP-); with NE challenge (SP+); reduced protein (1 to 2 percentage points lower CP) without NE challenge (RP-); with NE challenge (RP+); RP+ plus added Arg (103% of Ross 308 requirement, RPA+) and RPC+ where supplemental Arg-in RPA+ was replaced with Cit. The results of experiment 1 showed that birds fed the Arg-deficient RP diet tended to have lower total cecal ammonia levels (P = 0.054) on d 21, and had higher plasma ammonia levels on d 35 (P < 0.05) compared to those fed the SP. Supplementation of Arg-or Cit in the Arg-deficient RP diet reduced plasma ammonia level (P < 0.05) but did not affect total cecal ammonia level compared to the Arg-deficient RP treatment on d 35. Necrotic enteritis challenge decreased total cecal ammonia level (P < 0.01, experiment 1) while cyclic WT did not affect this parameter (experiment 2). Birds exposed to cyclic WT had a lower cecal formic acid level compared to those reared in NT on d 35 (P < 0.05). Preserving samples on ice or by snap freezing with liquid nitrogen during sample collection did not affect recovery of cecal ammonia. Determination of free ammonia level using an enzymatic assay using the Thermo Indiko Plus technique can be used to replace the Berthelot method as a quick assessment tool to evaluate cecal ammonia level in birds.

Chicken vision is sensitive to ultraviolet (UV) light containing the UVA spectrum, while UVB plays a key role in the endogenous production of vitamin D₃. However, commercially available light sources are typically deficient in the UV spectrum and thus may not adequately fulfill the lighting requirements of indoor-housed laying hens. We hypothesized that supplementary UVB light may improve egg production and egg quality, and bone health during early lay relative to UVA supplementation or standard control lighting. To investigate the effects of UV light supplementation, an experiment was conducted on 252 ISA Brown hens during 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UVO: standard control lighting with LED white light, (ii) UVA: control lighting plus supplemental daylight with an avian bulb, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Hen-day egg production and egg quality, blood parameters including plasma Ca and P, and serum 25(OH)D₃, and hen body weight and external health scoring were measured at different age points; while bone quality was assessed at the end of the experiment at 27 weeks. Data were analyzed in JMP® 16.0 using general linear mixed models with α level set at 0.05. Results showed that UVA and UVA/B supplemented birds reached sexual maturity (50% production) 3 and 1 day earlier, respectively, than control birds. There was a trend for UV lights to increase hen-day egg production (P = 0.06). Among egg quality traits, only eggshell reflectivity and yolk index were affected by UV lights (P = 0.02 and 0.01, respectively); however, most of the egg quality traits changed over age (all P < 0.01). Post-hoc tests showed higher serum 25(OH)D₃ in the UVA/B group relative to control hens (P < 0.05); but there was no treatment effect on plasma Ca and P or on bone quality parameters (all P > 0.05). A significant interaction was observed between light treatment and age for the number of comb wounds (P = 0.0004), with the UV supplemented hens showing more comb wounds after 24 weeks. These results demonstrated that supplemental UVA/B light had minimal effects on egg production and egg quality, whereas, UVA/B exposure may increase vitamin D₃ synthesis during the early laying period. The optimum duration of exposure and level of intensity needs to be determined to ensure these benefits.

The cylindrical conflorescences of the Banksia spinulosa Sm complex have several different colour types, i.e., black, red, maroon, lemon, and yellow. It is unknown if colour variation is due to extrinsic factors, importantly soil pH. Recent morphological observations have indicated that style colour are not contiguous, so follow-up chemical and soil analysis was conducted to further characterize the colour difference with respect to putative taxa and abiotic factors. Conflorescences of all known colours were sampled from across the eastern Australian distribution of B. spinulosa, and the respective soils were sampled and analysed for pH and total nitrogen. Regression analyses of this data demonstrated that pH and nitrogen gave nil and limited predictability for style colour respectively, i.e., only the taxa with black styles demonstrated a correlation, which was to a soil with slightly higher nitrogen content (p < 0.05). Furthermore, differences of pH were more often between taxa with conflorescences of the same colour. For chemical characterisation, the coloured styles were removed from conflorescences, extracted, and analysed by liquid chromatography-mass spectrometry (HPLC-MS/MS-DAD). Ten anthocyanin and twelve flavonol monoglycosides were identified by mass spectral fragmentation patterns (MS¹ and MS²) and retention times. The data demonstrates that style colour differences are caused by the concentration of anthocyanins and their specific chemistry. It remains to be determined if the differences of anthocyanin expression are caused by other abiotic factors, or if it is intrinsic to the respective taxon.

Ammonia (NH₃) emissions from manure can contribute to negative welfare outcomes for both humans and animals in livestock industries, and techniques to limit NH₃ volatilisation from the manure pad are being researched (McCrory and Hobbs 2001). Zeolite is a naturally occurring aluminosilicate present in sedimentary rock, compositionally similar to clay minerals but characterised by a unique three-dimensional structure and high cation exchange capacity that can selectively retain ammonium (NH₄⁺) ions (Ramesh and Reddy 2011). The current recommended application rates are highly variable, depending on industry application and particle diameter, and there is opportunity to investigate the capacity for adsorption of ambient NH₃ from the air. This experiment aimed to determine the most effective zeolite application rate for reduction of NH₃ volatilisation from the cattle manure pad, and to test ambient application of zeolite, in vitro.

Vitamin D metabolites provide a novel method to increase the efficiency of bodily phosphorus (P) and calcium (Ca) use by increasing absorption and retention along with inducing bone remodelling and deposition. These compounds may have potential application for livestock where P demand is high and in grazing environments that are deficient in P. The non-endogenous compound 1α-hydroxyvitamin D3 (1(OH)D3) utilised in the treatment of human osteoporosis bypasses the tightly regulated step of 1α-hydroxylase in the kidney to create the active hormone form of the vitamin, 1,25α dihydroxyvitamin D3. The few available ruminant studies have shown that it has a positive effect on blood P and Ca status but studies have been restricted to intramuscular injection over a relatively short period of time (Sachs et al. 1987; Naito et al. 1987; Braithwaite 1980). It was hypothesised that dietary 1(OH)D3 supplementation would have a positive and sustained effect on plasma phosphorus concentrations over an 84-day period, utilising sheep as a model ruminant.