Evaluation of the IceTag leg sensor and its derivative models to predict behaviour, using beef cattle on rangeland.

BACKGROUND: There is interest in using animal-mounted sensors to provide the detailed timeline of domesticated ruminant behaviour on rangelands. NEW METHOD: Working with beef cattle, we evaluated the pedometer-like IceTag device (IceRobotics, Edinburgh, Scotland) that records step events, leg movement and body position (upright versus lying). We used partition analysis to compare behaviour as inferred from the device data with true behaviour as coded at high resolution from carefully synchronized video observations of 5-min duration. RESULTS: Malfunctions reduced the target dataset by 7%. The correspondence between IceTag and video-coded step counts was excellent (r2=0.97), and the device's indications of upright or lying corresponded well (error rate=1.4%) to the video-coded values. However, the proportion of steps that could be matched individually was relatively low (65% at a tolerance of 0.5s), and the indicated start of a lying bout was often triggered by leg movements of an upright animal. Partition analysis of Grazing versus Not-Grazing yielded an overall error rate of 22%. In both three- and four-way classifications of behaviour (Graze, Rest, Travel; Graze, Stand, Lie, Travel) error rates were low for non-graze behaviours, but only 25% of Graze observations were correctly classified; the overall error rate was 22%. COMPARISON WITH EXISTING METHOD(S): The IceTag device performed well in mapping the diurnal patterns of animal position and step rate, but less well in separating grazing from upright resting. CONCLUSIONS: Our results suggest that pedometry is not the ideal method for classifying behaviour when grazing is of paramount interest.

Anthelmintic activity of Pistacia lentiscus foliage in two Middle Eastern breeds of goats differing in their propensity to consume tannin-rich browse.

The Damascus and Mamber breeds of goats thrive in Middle Eastern Mediterranean regions where the tannin-rich (20% of polyethylene glycol-binding tannins) brush species Pistacia lentiscus L. (lentisk) is ubiquitous. In light of the increasing recognition of the anthelmintic activity of plant tannins, we examined the effect of offering lentisk foliage for 24 days on fecal egg excretion in 5.5-month-old Damascus and Mamber kid goats (n=28) following infection with 10,000 L3 larvae of mixed gastro-intestinal nematodes (GIN). Lentisk foliage was consumed with or without a daily supplement of 20 g polyethylene glycol (PEG; MW 4000). Lentisk tannins showed a strong protein-depletive effect that was totally reversed by the addition of PEG. At the peak of infection, kids of the two breeds lost weight unless they were fed with lentisk without PEG. Fecal egg counts (FEC) were lowest - and did not differ from 0 - in kids fed lentisk without PEG, highest in the controls fed hay as roughage, and intermediate in kids fed lentisk and PEG (241, 1293, and 705 eggs per gram, respectively, SEM 180; P<0.001); therefore, the anthelmintic activity of lentisk was only partly attributable to tannins. The suppressive effect of lentisk on FEC ceased when feeding was discontinued, suggesting that female parasites were not killed but their fertility was reversibly impaired. Damascus kids showed lower FEC than their Mamber counterparts, inferring that the effect of foraging on tannin-rich species is only additive to genetic differences between goat breeds in their sensitivity to GIN infection. On the basis of our results we would expect yearlong lentisk grazing to result in no or very low GIN infection, and Damascus goats to have some advantage over Mamber goats where chemical control of GIN is unfeasible. There appears to be a trade-off between the benefits of lentisk tannin as drug and its side-effects (protein depletion) when given at high level; how goats balance this trade-off requires further elucidation.

Short-term changes in eating patterns explain the effects of condensed tannins on feed intake in heifers.

Ingestion of condensed tannins decreases feed intake in ruminants. Polyethylene glycol (PEG) forms high-affinity complexes with tannins. In two experiments carried out on Holstein heifers, quebracho (Q) from the Aspidosperma quebracho served as source of condensed tannins. The aims of the study were (i) to quantify the effect of Q on feed intake and eating behaviour in cattle fed complete mixed diets (CMDs); (ii) to clarify if changes induced in ingestive behaviour and feed intake by Q in cattle can be reversed by feeding PEG; and (iii) to clarify if the decrease in feed intake is associated with short-term (astringency, post-ingestive malaise) or longer-term effects. In experiment 1, 500 g/day of Q was found to be the minimal dose that decreased feed intake in heifers. A ratio of PEG:Q equal to 1:12.5 did not fully restore feed intake. In experiment 2, four heifers received a random sequence of four rations in a Latin-square design with feeding cycles of ca. 7 days: CMD containing no supplements (C), or supplemented with 625 g/day of Q without PEG (Q), with 625 g/day of Q and 250 g/day of PEG (Q-PEG), or with 250 g/day of PEG without Q (PEG). Individual rations were continuously weighed in the trough and the behaviour of heifers was observed for 180 min after distribution of CMD. Overall, feeding Q was associated with lowered feed intake and shorter duration of eating bouts, mainly of the first eating bout, immediately after distribution of the diet. A larger portion of the diet was consumed subsequent to 180 min after distribution in Q-fed heifers. Eating rate and the water to food ratio were not affected by Q. The effects of Q on feed intake were attenuated by feeding PEG. Heifers adapted effectively to condensed tannins by increasing the number of eating bouts and the portion of diet consumed subsequent to 180 min after distribution, so that no differences in feed intake were noted on the last day of each feeding cycle. Data are interpreted to show that: (i) negative effects of Q on feed intake derive from astringency of CT and short-term post-ingestive malaise; (ii) the increased number of eating bouts and their wider partition throughout the day are means to preserve the ruminal environment in Q-fed heifers; (iii) PEG has the potential to neutralize negative effects of condensed tannins in cattle.

Quantitative verification of the existence of high molecular weight protein aggregates in the intact normal human lens by light-scattering spectroscopy.

The method of quasi-elastic light-scattering spectroscopy was used to establish quantitatively the concentration of high mmolecular weight (HMW) aggregates present in the normal human intact lens as a function of age. The concentration of HMW proteins increases monotonically with age. HMW proteins are absent in the infant lens, but represent 3% of the total soluble lens protein at age 60 years. The percent concentration of HMW proteins measured in intact lenses of various ages by quasi-elastic light scattering is in striking agreement with values determined biochemically.