Timing and Duration of Observation Periods of Foraging Behavior in Natural Grasslands.

The goals of this study were to evaluate the length of time grazing which should be monitored over a 24-h period to predict the grazing behavior of beef heifers within a season and determine the patterns of foraging activity over 24 h. A database was constructed between 2010 and 2012 for beef heifers managed under rotational grazing in a natural grassland. Grazing, rumination, and other activity times were assessed visually during 24 h on 15 occasions. Data were classified according to climatic seasons, generating 12 replicates in summer, 18 in spring, 24 in autumn, and 36 in winter. Treatments were the evaluation of four distinct periods: from sunrise to sunset (DAY-SUN), daylight duration from dawn to nightfall (DAYLIGHT), DAYLIGHT plus 2 h (DAYLIGHT+2), DAYLIGHT to midnight (DAYLIGHT to 0), and the entire 24 h period (CONTROL). Differences for grazing, rumination, and other activities were found in all seasons for the evaluation periods. Sampling sufficiency was reached only with the DAYLIGHT to 0 and CONTROL for all four climatic seasons. The DAYLIGHT to 0 treatment covered 75% of a 24-h period and 95% of the mean foraging time took place during this time interval. Considering grazing distribution during a day, in the warm seasons, the major grazing period during mornings occurred earlier than in the cool seasons, and in cool seasons, the grazing peak was observed during the afternoon. Visual observations from dawn until midnight represented the total grazing time and natural behavior of heifers and could be used to represent grazing activities for the entire day.

Audio recordings dataset of grazing jaw movements in dairy cattle.

This dataset is composed of correlated audio recordings and labels of ingestive jaw movements performed during grazing by dairy cattle. Using a wireless microphone, we recorded sounds of three Holstein dairy cows grazing short and tall alfalfa and short and tall fescue. Two experts in grazing behavior identified and labeled the start, end, and type of each jaw movement: bite, chew, and chew-bite (compound movement). For each segment of raw audio corresponding to a jaw movement we computed four well-known features: amplitude, duration, zero crossings, and envelope symmetry. These features are in the dataset and can be used as inputs to build automated methods for classification of ingestive jaw movements. Cow's grazing behavior can be monitored and characterized by identifying and analyzing these masticatory events.

The Order of Grass and Maize Silage Supplementation Modifies Milk Yield, Grazing Behavior and Nitrogen Partitioning of Lactating Dairy Cows.

The aim of this study was to evaluate the effects of the order of grass silage (GS) and maize silage (MS) supplementation on milk yield, grazing behavior and nitrogen (N) partitioning of lactating dairy cows during autumn. Thirty-six Holstein-Friesian dairy cows were randomly assigned to one of three treatments, and cows remained on these treatments for a 62 days period: (1) MIX; cows supplemented with 3 kg of dry matter (DM) of silage containing 1.5 kg DM of MS and 1.5 kg DM of GS in both the morning and afternoon; (2) GS-MS; cows supplemented with 3 kg DM of GS in the morning and 3 kg DM of MS in the afternoon; (3) MS-GS; cows supplemented with 3 kg DM of MS in the morning and 3 kg DM of GS in the afternoon. All cows received a pasture allowance of 17 kg DM/cow/d and 3 kg DM of concentrate. Grazing time and pasture intake were unaffected by treatment; however, milk production was greater for MS-GS, while milk protein was greater for GS-MS. Urinary N excretion was greater for MS-GS than MIX. In conclusion, MS-GS resulted in high milk yield but also high urinary N excretion, while MIX resulted in low urinary N excretion but also decreased milk yield.

Physiological responses and animal behavior in Bonsmara-Hereford crosses vs. Hereford purebred on environment stress

Adaptative traits (rectal temperature-RT, respiratory rate-RR) and grazing behavior (Grazing, Ruminating and Rest time, and Sun or Shade time) of Bonsmara-Hereford crossbred-BH, n = 15, and purebred Hereford-HH, n = 18, yearling heifers, in a grazing system of Uruguay. Environment characterization was made using THIadjusted by radiation and wind speed (no, mild, and severe heat weaves), and the comprehensive climatic index-CCI (no, middle, moderate and severe stress). Adaptative traits were measured twice a day, weekly, in two consecutive days in summer and winter at 08h00 and 16h00. Grazing behavior was observed from 07h00 to 21h00 each 600 s twice in summer. The records were analyzed using a mixed model. Significant effect of genotype was observed in mild heat waves for RR and RT in the afternoon (BH lower than HH). For CCI in a.m., the RR was lower than HH in BH in severe stress, while in p.m., the RR was lower in all of CCI levels. RT in p.m. in moderate and severe was lower in BH than in HH. In winter, no differences were found. In grazing behavior, HH rests longer than BH doe; also, HH spends more time in the shade (34 %) than BH does (22 %). BH genotype showed better thermoregulation and grazing behavior at higher temperatures compared to HH.(AU)

Physiological responses and animal behavior in Bonsmara-Hereford crosses vs. Hereford purebred on environment stress

ABSTRACT: Adaptative traits (rectal temperature-RT, respiratory rate-RR) and grazing behavior (Grazing, Ruminating and Rest time, and Sun or Shade time) of Bonsmara-Hereford crossbred-BH, n = 15, and purebred Hereford-HH, n = 18, yearling heifers, in a grazing system of Uruguay. Environment characterization was made using THIadjusted by radiation and wind speed (no, mild, and severe heat weaves), and the comprehensive climatic index-CCI (no, middle, moderate and severe stress). Adaptative traits were measured twice a day, weekly, in two consecutive days in summer and winter at 08h00 and 16h00. Grazing behavior was observed from 07h00 to 21h00 each 600 s twice in summer. The records were analyzed using a mixed model. Significant effect of genotype was observed in mild heat waves for RR and RT in the afternoon (BH lower than HH). For CCI in a.m., the RR was lower than HH in BH in severe stress, while in p.m., the RR was lower in all of CCI levels. RT in p.m. in moderate and severe was lower in BH than in HH. In winter, no differences were found. In grazing behavior, HH rests longer than BH doe; also, HH spends more time in the shade (34 %) than BH does (22 %). BH genotype showed better thermoregulation and grazing behavior at higher temperatures compared to HH.

Physiological responses and animal behavior in Bonsmara-Hereford crosses vs. Hereford purebred on environment stress

ABSTRACT: Adaptative traits (rectal temperature-RT, respiratory rate-RR) and grazing behavior (Grazing, Ruminating and Rest time, and Sun or Shade time) of Bonsmara-Hereford crossbred-BH, n = 15, and purebred Hereford-HH, n = 18, yearling heifers, in a grazing system of Uruguay. Environment characterization was made using THIadjusted by radiation and wind speed (no, mild, and severe heat weaves), and the comprehensive climatic index-CCI (no, middle, moderate and severe stress). Adaptative traits were measured twice a day, weekly, in two consecutive days in summer and winter at 08h00 and 16h00. Grazing behavior was observed from 07h00 to 21h00 each 600 s twice in summer. The records were analyzed using a mixed model. Significant effect of genotype was observed in mild heat waves for RR and RT in the afternoon (BH lower than HH). For CCI in a.m., the RR was lower than HH in BH in severe stress, while in p.m., the RR was lower in all of CCI levels. RT in p.m. in moderate and severe was lower in BH than in HH. In winter, no differences were found. In grazing behavior, HH rests longer than BH doe; also, HH spends more time in the shade (34 %) than BH does (22 %). BH genotype showed better thermoregulation and grazing behavior at higher temperatures compared to HH.

Morphological and physiological responses of seagrasses (Alismatales) to grazers (Testudines: Cheloniidae) and the role of these responses as grazing patch abandonment cues / Respuestas morfológicas y fisiológicas de los pastos marinos (Alismatales) a los herbívoros (Testudines: Cheloniidae) y el papel de estas respuestas como señales de abandono de parches de pastoreo

Green sea turtles, Chelonia mydas, are grazers influencing the distribution of seagrass within shallow coastal ecosystems, yet the drivers behind C. mydas patch use within seagrass beds are largely unknown. Current theories center on food quality (nutrient content) as the plant responds to grazing disturbances; however, no study has monitored these parameters in a natural setting without grazer manipulation. To determine the morphological and physiological responses potentially influencing seagrass recovery from grazing disturbances, seagrasses were monitored for one year under three different grazing scenarios (turtle grazed, fish grazed and ungrazed) in a tropical ecosystem in Akumal Bay, Quintana Roo, Mexico. Significantly less soluble carbohydrates and increased nitrogen and phosphorus content in Thalassia testudinum were indicative of the stresses placed on seagrasses during herbivory. To determine if these physiological responses were the drivers of the heterogeneous grazing behavior by C. mydas recorded in Akumal Bay, patches were mapped and monitored over a six-month interval. The abandoned patches had the lowest standing crop rather than leaf nutrient or rhizome soluble carbohydrate content. This suggests a modified Giving Up Density (GUD) behavior: the critical threshold where cost of continued grazing does not provide minimum nutrients, therefore, new patches must be utilized, explains resource abandonment and mechanism behind C. mydas grazing. This study is the first to apply GUD theory, often applied in terrestrial literature, to explain marine herbivore grazing behavior.

Las tortugas verdes, Chelonia mydas, son herbívoros que influencian la distribución de pastos marinos en sistemas costeros someros, sin embargo los factores que hay detrás del uso de un parche de pastos marinos por C. mydas son desconocidos. Teorías actuales se centran en calidad de alimento (contenido de nutrientes en tejido) conforme la planta responde a la alteración causada por el pastoreo; sin embargo no hay estudios que hayan monitoreado estos parámetros en un diseño natural sin manipulación del herbívoro. Para deter minar las respuestas morfológicas y fisiológicas (productividad, morfología y almacenamiento de nutrientes) que potencialmente influencian la recuperación de los pastos de la alteración por pastoreo, los pastos fueron monitoreados por un año en tres escenarios diferentes de pastoreo (pastoreo por tortuga, pastoreo por peces, sin pastoreo) en el sistema tropical Bahía de Akumal, Quintana Roo, México. Significativamente menos carbohidratos solubles y mayor contenido de nitrógeno y fósforo fueron indicativos del estrés causado por el pastoreo en los pastos. Para determinar si estas respuestas fisiológicas de los pastos son las causantes del heterogéneo comportamiento de pastoreo de C. midas, reportado en Akumal, se mapearon y monitorearon parches de pastos en intervalos de seis meses. Los parches abandonados tuvieron menor biomasa, en vez de bajo contenido de nutrientes en hoja, o de carbohidratos en raíces. Estos resultados sugieren un comportamiento modificado de renunciamiento por densidad: el umbral crítico donde el costo de pastoreo continuo no provee los nutrimentos mínimos, por lo tanto nuevos parches deberán ser utilizados, explicando así el abandono del recurso y mecanismo detrás del comportamiento de pastoreo por C. mydas. Este es el primer estudio en aplicar la teoría de renuncia por densidad, frecuentemente utilizada en la literatura terrestre, para explicar el comportamiento de pastoreo de herbívoros.

Productive and Economic Responses in Grazing Dairy Cows to Grain Supplementation on Family Farms in the South of Brazil.

Pasture-based dairy production has been a major source of income for most family farms in the south of Brazil. Increasing milk prices have spurred an increase in grain supplementation, which has been poorly implemented, resulting in low levels of efficiency. To evaluate the consequences of supplementation on milk production and composition, grazing behavior and economic return, the widely used grain management system (CC-commercial concentrate, containing 21% CP, offered at 1 kg per 3.7 L of milk) was compared with an energy supplement (GC-ground corn, with 9.5% CP, offered at 0.4% of live weight). Ten Holstein cows were paired into two groups, and subjected to the two treatments in a crossover design. The cows remained in the same grazing group, and the grain supplement was offered individually at milking time and consumed completely. Each experimental period lasted 14 days, with 10 days for diet adaptation and four days for data collection; individual milk production and samples were collected to determine levels of fat, protein, lactose, carotenoids, vitamin A and N-urea. Grazing behavior was observed (scans every 5 min) in the first 4 h after the morning milking, and chemical composition of hand plucked samples of forage were measured. The cost of the supplement and profitability per treatment were calculated. Cows supplemented with GC consumed herbage with higher crude protein (CP: 16.23 vs. 14.62%; p < 0.05), had higher biting rate (44.21 vs. 39.54 bites/min; p < 0.03) and grazing time (22.20 vs. 20.55 scans; p < 0.05) than when receiving CC. There were no differences in milk composition between treatments (p > 0.05). However, higher concentrations of ß-carotene and total carotenoids were detected in the milk of cows at 70-164 days of lactation, compared to <70 days of lactation (p < 0.05). Milk production was higher (13.19 vs. 11.59 kg/day; p < 0.05) when cows consumed CC, but resulted in lower profitability compared to GC (US$ 4.39 vs. US$ 4.83/cow per day). Our results show that higher productivity does not necessarily improve profitability. Cows receiving supplement with lower levels of protein were able to adjust their grazing behavior to meet their protein needs and this level of diet modification did not alter milk composition.