Grazing Behavior and Locomotion of Young Bulls Receiving Different Nutritional Plans in a Tropical Pasture

Abstract

The objectives of this study were to compare visual observation and an electronic grazing time method and to evaluate the effects of nutritional plans on intake, grazing behavior and horizontal and vertical locomotion of young bulls in a tropical pasture. Thirty-nine Nellore young bulls with an average body weight of 345±9.3 kg kept in pasture were used. The experimental treatments consisted of: restricted: animals kept in a plot with a low mass of forage receiving mineral mixture only; control: animals receiving mineral mixture only; HPHC: a high protein and high carbohydrate supplement; HPLC: a high protein and low carbohydrate supplement; LPHC: a low protein and high carbohydrate supplement; LPLC: a low protein and low carbohydrate supplement. GPS collars equipped with activity sensors were used. Information about head position, latitude, longitude and altitude were recorded. Daytime grazing behavioral patterns monitored by a continuous focal animal recording method was compared to behavior estimated by the activity sensor. Feed intake was estimated by a marker method. The Restricted group presented lower (p<0.05) intake of dry matter and TDN. However, difference in dry matter intake was not found (p>0.05) between non-supplemented and supplemented animals. Difference was not found (p>0.05) in daytime grazing time obtained by visual observation or the activity sensor method. The restricted group showed longer (p<0.05) grazing time (9.58 h/d) than other groups, but difference was not found (p>0.05) in the grazing time between Control (8.35 h/d) and supplemented animals (8.03 h/d). The Restricted group presented lower (p<0.05) horizontal locomotion distance (2,168 m/d) in comparison to other groups (2,580.6 m/d). It can be concluded that the use of activity sensor methods can be recommended due to their being similar to visual observation and able to record 24-h/d. While supplements with high carbohydrates reduce pasture intake, they do not change grazing behavior. Moderate supplementation (until 50% of protein requirement and 30% of energy requirement) of beef cattle on tropical pasture has no effect on daily locomotion.

Use of GPS tracking collars on Sarda cattle in a Silvopastoral System

“…The proportion of individuals fitted with GPS over the whole herd in this work was 25%. According to [16] behavioral assessment of few individuals, into of a group, may estimate the behavior of entire group. As a GPS fix was collected in 94% of attempts and standard deviation (7.2s) of the fixes was low, each point was accepted as representing equal time portions [17].…”

Grazing behavior of non-supplemented and supplemented heifers on Italian ryegrass pasture

“…Average temperature during the period within this stage (23.3°C) was 4°C higher than average temperature during the vegetative stage. Grazing time may change due to temperature, as ruminants reduce ingestion and increase heat loss to conserve body temperature at the appropriate physiological level (VALENTE et al, 2013).…”

The Value of ‘Cow Signs’ in the Assessment of the Quality of Nutrition on Dairy Farms

“…Enough room for all cattle to feed at the same time is required for good food utilization and better production [ 9 , 102 , 103 ]. In pasture-based systems the stocking density on a paddock/break depends on the same factors as for feedlot-based systems in addition to the pasture/crop quality and quantity, amount of supplemental feed, antecedent experiences of each individual, and current environmental and social conditions [ 45 , 83 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 ]. This is important, as cattle are social animals and eat at the same time, often referred to as ‘social facilitation’ [ 9 , 10 , 112 , 113 ].…”

“…Chewing movements during ingestion of feedstuffs, and/or time spent eating, have been incorporated into some automatic devices of recording cow behavior for the purposes of the detection of estrus or impending parturition and health [ 10 , 117 , 126 , 133 , 143 , 145 , 152 , 153 ]. Other electronic devices, such as electronic gates and geo-spatial identification readers, can be used to measure the time that individual dairy cattle spend at the bunk/feedpad/grazing [ 110 , 154 , 155 ].…”