Behavioral Adaptations of Nursing Brangus Cows to Virtual Fencing: Insights from a Training Deployment Phase.

Virtual fencing systems have emerged as a promising technology for managing the distribution of livestock in extensive grazing environments. This study provides comprehensive documentation of the learning process involving two conditional behavioral mechanisms and the documentation of efficient, effective, and safe animal training for virtual fence applications on nursing Brangus cows. Two hypotheses were examined: (1) animals would learn to avoid restricted zones by increasing their use of containment zones within a virtual fence polygon, and (2) animals would progressively receive fewer audio-electric cues over time and increasingly rely on auditory cues for behavioral modification. Data from GPS coordinates, behavioral metrics derived from the collar data, and cueing events were analyzed to evaluate these hypotheses. The results supported hypothesis 1, revealing that virtual fence activation significantly increased the time spent in containment zones and reduced time in restricted zones compared to when the virtual fence was deactivated. Concurrently, behavioral metrics mirrored these findings, with cows adjusting their daily travel distances, exploration area, and cumulative activity counts in response to the allocation of areas with different virtual fence configurations. Hypothesis 2 was also supported by the results, with a decrease in cueing events over time and increased reliance with animals on audio cueing to avert receiving the mild electric pulse. These outcomes underscore the rapid learning capabilities of groups of nursing cows in responding to virtual fence boundaries.

Real-Time Monitoring of Grazing Cattle Using LORA-WAN Sensors to Improve Precision in Detecting Animal Welfare Implications via Daily Distance Walked Metrics.

Animal welfare monitoring relies on sensor accuracy for detecting changes in animal well-being. We compared the distance calculations based on global positioning system (GPS) data alone or combined with motion data from triaxial accelerometers. The assessment involved static trackers placed outdoors or indoors vs. trackers mounted on cows grazing on pasture. Trackers communicated motion data at 1 min intervals and GPS positions at 15 min intervals for seven days. Daily distance walked was determined using the following: (1) raw GPS data (RawDist), (2) data with erroneous GPS locations removed (CorrectedDist), or (3) data with erroneous GPS locations removed, combined with the exclusion of GPS data associated with no motion reading (CorrectedDist_Act). Distances were analyzed via one-way ANOVA to compare the effects of tracker placement (Indoor, Outdoor, or Animal). No difference was detected between the tracker placement for RawDist. The computation of CorrectedDist differed between the tracker placements. However, due to the random error of GPS measurements, CorrectedDist for Indoor static trackers differed from zero. The walking distance calculated by CorrectedDist_Act differed between the tracker placements, with distances for static trackers not differing from zero. The fusion of GPS and accelerometer data better detected animal welfare implications related to immobility in grazing cattle.

Herbage mass and allowance and animal genotype affect daily herbage intake, productivity, and efficiency of beef cows grazing native subtropical grassland.

The beef sector in Campos grasslands must increase animal productivity without external inputs, while reducing environmental impact. The objective of this study was to estimate herbage intake (g/metabolic body weight [MBW]/d) of straightbred (Hereford/Angus) and crossbred (F1 of Hereford × Angus) beef cows grazing subtropical native grassland with High and Low herbage allowance (HA, 5 vs. 3 kg DM/kg bodyweight [BW]) during gestation and lactation and its relationship with biological efficiency of cow-calf productivity. Herbage intake (estimated via n-alkanes C32:C33 ratio) was measured during early (Ge1, -163 d prior calving) and mid to late [Gm1 (-83) and Gm2 (-90 d prior calving)] gestation and lactation (L0, L1, and L2, 60, 47, and 31d following calving) periods in 24 to 36 cows, selected to create 8 groups (4 per block) of HA × cow genotype treatment. Cows grazed native grassland year-round, under High and Low HA (except in winter). We analyzed the effect of cow genotype (straightbred vs. crossbred cows) and HA (High vs. Low) on herbage mass and height, daily herbage intake rate (DMI), cow body condition score (BCS), calf average daily gain (ADG) and BW at weaning (BWW) and g of calf weaned/kg DMI. High allowance improved DMI during lactation periods (High 115.6 vs. Low 94.1 ± 5.3; P < 0.05 g/MBW/d). Crossbred cows decreased DMI during gestation (Crossbred 81 vs. Straightbred 94 ± 4.3; P = 0.05 g/MBW/d) compared with straightbred cows. Crossbred and High HA improved biological efficiency, 40.0 vs. 26.2 and 36.0 vs. 29.7 g of calf/kg DMI, respectively. High allowance increased herbage mass and sites with greater canopy height that allow greater DMI, positively associated with cow BCS at weaning, calf ADG, BWW, and g of calf/kg DMI. Crossbred cows reduced DMI during gestation showing no greater annual DMI. Animal productivity and biological efficiency can be improved using High HA and crossbred cows, which should decrease the environmental impact of cow-calf systems.

Growth and Reproductive Performance of Rangeland Beef-Cattle as Influenced by Controlled and Uncontrolled Populations of Horn Flies (Diptera: Muscidae).

A 4-yr study was conducted on native rangeland to assess the growth and reproductive performance of cows (Bos taurus) infested with naturally occurring seasonal populations of horn flies (Haematobia irritans). One hundred five Angus × Hereford cow-calf pairs were evaluated as a randomized complete block that was replicated across 4 yr. Cows were approximately 39 d postpartum at the beginning of each yearly trial and were randomly allocated to either an untreated control (UTC) or an insecticide-treated (TRT) herd. Horn fly populations were monitored throughout each yearly replication and blood serum progesterone levels were used to estimate postpartum interval lengths and days to pregnancy. Initial body weights of cows were collected in May with final body weights and calf weaning weights acquired in October of each year. Monthly horn fly control ranged from 85.55 to 99.57% throughout the 4 yr. Cows within UTC herds maintained on average 530.10 ± 94.74 more (P = 0.0015) flies per animal than TRT. However, no differences were detected between treatment groups for any of the reproductive parameters evaluated (P > 0.05). Despite a lack of difference in the reproductive parameters measured, TRT cows gained more (P = 0.0492) weight throughout the fly seasons when compared to UTC cattle. Furthermore, calves paired with insecticide-treated cows tended (P = 0.0680) to wean 16.28 ± 8.04 kg heavier than calves paired with cows exposed to naturally occurring horn fly populations.

Behavioral Responses of Cattle to Naturally Occurring Seasonal Populations of Horn Flies (Diptera: Muscidae) Under Rangeland Conditions.

The behavioral responses of cattle under the influence of naturally occurring seasonal horn fly, Haematobia irritans (L.), populations were evaluated under rangeland conditions. This study was replicated four times using 10 cows as the subsampling unit equipped with GPS collars scheduled to receive locational fixes every 5 min for 6 d prior to, and 6 d following horn fly insecticidal control application. Data derived from GPS collars were used to evaluate potential horn fly-induced behavioral modifications expressed during predawn, daytime, and nighttime periods. These data were used to analyze variables, which included distance travelled, daily area explored, vertical and horizontal head movements, and inferred activities such as resting, grazing, and walking. Horn fly populations were estimated using daily visual counts and were reduced significantly on animals following insecticidal application. There was no significant difference between treatment periods in any of the aforementioned analyzed variables. During the night-time hours estimated differences (pretreatment minus posttreatment) for distance travelled, area explored, and vertical head movements were 0.81 ± 0.46 km/d, 0.35 ± 0.21 km(2)/d, and 7.25 ± 5.30 counts/d, respectively. The implications of these observations are discussed.