Intake behaviors of yearling steers grazing irrigated pasture and receiving either a free-choice salt-based mineral or a low-moisture molasses-based tub mineral

Association of rainfall pattern with the disappearance of mineral mixtures fed cattle managed on tropical pastures

The objective of the present study was to evaluate the association between rainfall and the disappearance of mineral mixtures in the supplementation of cattle on pasture. Supplement consumption and rainfall data were obtained from five experiments carried out between 2016 and 2022. The experiments lasted from 84 to 126 days and had 12 to 18 paddocks formed by Brachiaria spp. under grazing by beef cattle (n = 544), receiving mineral supplementation. Supplement disappearance (SD), difference between the amount offered and leftovers (considering intake and losses) and precipitation (PR), was measured over periods of 14 to 21 days. The periods (n = 565) were classified as very dry, dry, normal, rainy, and very rainy, using the Quantis method. The number of rainy days (RD) and the average precipitation per RD (APRD) per period and the average body weight (BW) of the animals in the periods were also determined. Linear regression analyses assessed the association between BW, PR, RD, and APRD. The average PR in the periods studied was 68.5 mm, ranging from 0.00 to 160.3 mm. Each period had up to six RD, with up to 129.5 mm precipitated. The average BW was 270 kg, ranging from 208 to 335 kg and the average SD was 82.2 g/animal/day, ranging from 0.52 to 176.7 g/animal/day. Differences in RD and APRD are consistent across precipitation classes. In the regression analysis, the model with the highest coefficient of determination was the one that contained the linear and quadratic terms for the RD variable. Including linear and quadratic terms of all variables in a multiple regression represented more than half of the variation in the disappearance of the supplement (R2 = 0.5823). There is no clear relationship between the intensity of precipitation, reflected in the form of classes, and the disappearance of supplements offered to cattle on pasture since dry and very rainy periods can be equivalent. However, variables that characterize the precipitation pattern are more relevant than animal live weight to explain existing variations in supplement disappearance. Among them, the frequency with which precipitation occurs (number of rainy days in the period) seems to be more important than the precipitation rate itself, probably because it is related to the volume of precipitation accumulated in the period.

Powder and agglomerated free-choice minerals for grazing cattle: animal responses and chemical and physical alterations of the mineral mixture

The aim was to evaluate the animal response and the chemical and physical changes of free-choice mineral mixtures fed to grazing cattle. Growing beef cattle were fed either powder (POW) or agglomerated (AGL) mineral mixtures in three different experiments (Exp.), carried out in pastures of Brachiaria grass. In Exp. 1 and 2, the mineral mixtures were disposed in unsheltered troughs (POWun vs. AGLun), being delivered once (D0, Exp.1) or twice (D0 and D8, Exp. 2), throughout 14-day periods. In Exp. 3, POWun and AGLun were additionally compared to POW in sheltered troughs (POWshe), and the mineral mixtures were disposed in D0, throughout 21-day periods. Non-consumed supplement was removed and sampled on D14 (Exp. 1 and 2) or D21 (Exp. 3). Evaluations included average daily body weight gain (ADG), daily disappearance of the supplement (DSD), penetration force of the supplement mass, faecal chemical composition and serum levels of Ca, P and Mg. In Exp. 1, no effects were observed on ADG and faecal mineral concentrations, however, changes in mineral concentrations and a 40% reduction in Na concentration in the supplement were observed, compared to the initial concentration. AGLun had a lower penetration force. In Exp. 2, there were no effects on DSD and faecal mineral concentrations. POWun showed a smaller reduction in Na content compared to AGLun, and AGLun showed lower penetration force. In Exp. 3, the treatments did not affect ADG, but there was a trend towards higher DSD and serum phosphorus (P) concentration for AGLun (p = 0.08). Higher faecal Na concentration was observed for AGLun and higher Na concentration occurred in non-consumed mixture of POWshe. Mineral supplements offered in uncovered troughs showed altered chemical and physical characteristics, with possible effects on supplement intake. However, the general changes are unlikely to alter animal performance.

Influence of hay feeding method, supplement moisture, or access time on intake and waste by beef cows

Experiments were performed to determine the effects of feeding method and hay processing (Experiment 1), energy supplement moisture content and feeding method (Experiment 2), and access time to hay (Experiment 3) on cow body weight (BW), dry matter intake (DMI), and hay or energy supplement intake and waste. Experiment 1 was designed as a 4 × 4 Latin Square using 48 multiparous, late-gestating, Angus cows (626 kg initial BW). Cows were stratified by age and BW into four treatment groups (n = 12 cows/group); treatment groups were then initially assigned randomly to treatments in a sequence of preset Latin Square periods. In Experiment 1, round bales were processed and delivered on the pen surface or in a bunk, or left unprocessed and delivered in a hay ring or rolled out on the pen surface. Experiment 2 was designed as a 6 × 6 Latin Square utilizing 54 multiparous, late-gestating, Angus cows (616 kg initial BW). Cows were stratified by age and BW into treatment groups (n = 9 cows/group); treatment groups were then initially assigned randomly to treatments in a sequence of preset Latin Square periods. In Experiment 2, corn screenings (CS) or wet beet pulp (BP) were fed in a structure (inverted tire or bunk) or BP only on the pen surface. Experiment 3 was designed as a replicated 3 × 3 Latin Square utilizing 24 multiparous, late-gestating, Angus cows (584 kg initial BW). Cows were stratified by age and BW into treatment groups (n = 8 cows/group); treatment groups were then initially assigned randomly to treatments in a sequence of preset Latin Square periods. In Experiment 3, cows were permitted access to round-bales in a hay ring for 6, 14, or 24 h. In Experiment 1, hay DMI was not affected (P ≥ 0.579). Hay waste was greater (P ≤ 0.007) when hay, processed or not, was fed on the pen surface. In Experiment 2, hay DMI was greatest (P ≤ 0.011) for cows fed no supplement and those fed CS in a bunk. Feeding BP in a bunk led to the greatest (P ≤ 0.003) hay waste. In Experiment 3, cows permitted 6-h access consumed and wasted less (P < 0.001) hay compared with those permitted longer access; BW was unaffected (P ≥ 0.870). In these experiments, cows fed hay on the pen surface, processed or not, achieved similar DMI as those fed in a ring or bunk, but wasted more hay. Delivering BP in a bunk or on the pen surface increased hay and supplement waste, respectively. Controlling access to hay reduced DMI and waste while maintaining cow BW.

A Pilot Study Using Accelerometers to Characterise the Licking Behaviour of Penned Cattle at a Mineral Block Supplement

Simple Summary

Quantifying mineral block supplement intake by individual beef cattle is a challenging task but may enable improved efficiency of supplement use particularly in a grazed system. Estimating time spent licking when cattle access the mineral block supplement can be useful for predicting intake on an individual basis. The advancement of sensor technology has facilitated collection of individual data associated with ingestive behaviours such as feeding and licking duration. This experiment was intended to investigate the effectiveness of wearable tri-axial accelerometers fitted on both neck-collar and ear-tag to identify the licking behaviour of beef cattle by distinguishing it from eating, standing and lying behaviours. The capability of tri-axial accelerometers to classify licking behaviour in beef cattle revealed in this study would offer the possibility of measuring time spent licking and further developing a practical method of estimating mineral block supplement intake by individual grazing cattle.

Abstract

Identifying the licking behaviour in beef cattle may provide a means to measure time spent licking for estimating individual block supplement intake. This study aimed to determine the effectiveness of tri-axial accelerometers deployed in a neck-collar and an ear-tag, to characterise the licking behaviour of beef cattle in individual pens. Four, 2-year-old Angus steers weighing 368 ± 9.3 kg (mean ± SD) were used in a 14-day study. Four machine learning (ML) algorithms (decision trees [DT], random forest [RF], support vector machine [SVM] and k-nearest neighbour [kNN]) were employed to develop behaviour classification models using three different ethograms: (1) licking vs. eating vs. standing vs. lying; (2) licking vs. eating vs. inactive; and (3) licking vs. non-licking. Activities were video-recorded from 1000 to 1600 h daily when access to supplement was provided. The RF algorithm exhibited a superior performance in all ethograms across the two deployment modes with an overall accuracy ranging from 88% to 98%. The neck-collar accelerometers had a better performance than the ear-tag accelerometers across all ethograms with sensitivity and positive predictive value (PPV) ranging from 95% to 99% and 91% to 96%, respectively. Overall, the tri-axial accelerometer was capable of identifying licking behaviour of beef cattle in a controlled environment. Further research is required to test the model under actual grazing conditions.