Development of a methodology for studying feeding station behaviour of grazing ewes

Roguet, Christine; Prache, Sophie; Petit, M.

doi:10.1016/s0168-1591(97)00044-0

Cited by 7 publications

(6 citation statements)

References 18 publications

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“…Segundo Roguet et al (1998), os animais tendem a explorar a estação de pastejo ou estação alimentar, que foi definida em Carvalho et al (1999) como uma área hipotética disponível ao animal, a qual ele alcançaria sem mover as suas patas dianteiras, por estratos, especialmente em perfis mais altos. Isto pôde ser observado neste experimento, pois no segundo dia de ocupação dos piquetes pelos animais a maioria das pontas das folhas estava colhida.…”

Section: Resultsunclassified

Avaliação de três cultivares de Panicum maximum Jacq. sob pastejo: disponibilidade de forragem, altura do resíduo pós-pastejo e participação de folhas, colmos e material morto

Brâncio¹,

Euclides

Júnior³

et al. 2003

R. Bras. Zootec.

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RESUMO -Três cultivares dePanicum maximum Jacq. submetidos a pastejo rotativo foram avaliados ao longo do ano, antes e após o período de pastejo, quanto às disponibilidades de matéria seca total e de folhas, altura, profundidade pastejada, densidade, participações de folhas, colmos e material morto, relações folha/colmo e folha/material morto. Os tratamentos constituíram em: 1) cv. Tanzânia + 50 kg/ha de N, 2) cv. Tanzânia + 100 kg/ha de N, 3) cv. Mombaça + 50 kg/ha de B e 4) cv. Massai + N 50 kg/ha de N. O cultivar Mombaça apresentou menores disponibilidades de folhas, e maiores proporções de colmo, enquanto o cv. Massai tanto apresentou características que poderiam favorecer a seleção de folhas, como maior densidade de MS e maior relação folha/colmo, como a característica desfavorável de apresentar menor relação folha/material morto. No cv. Tanzânia, a adubação nitrogenada no final do período chuvoso trouxe benefícios apenas em março, quando houve aumento nas relações folha/colmo e folha/material morto. A profundidade pastejada correlacionou-se positivamente com a altura, e os animais pastejaram em média 41% da altura da pastagem, no período seco, e 47% no período chuvoso. ABSTRACT-Three cultivars of Panicum maximum Jacq. under rotational grazing were evaluated for one year, before and after grazing, when measurements were made of the availability of total dry matter, height, residual dry matter, forage density, leaf dry matter, participation of leaves, stems and dead material, and ratios of leaf:stem and leaf:dead plant material. The treatments were 1) v. Tanzania + 50 kg N/ha, 2) v. Tanzania + 100 kg N/ha, 3) v. Mombaça + 50 kg N/ha, and 4) v. Massai + 50 kg N/ha. The Mombaça cultivar presented the poorest results, lowest production of leaves and the highest proportion of stems. However, the cv. Massai deservers attention for characteristics such as higher density of DM and higher leaf lamina:stem ratio; however, it presented a lower ratio of leaves:dead material. There were no significant differences in percentage of leaves among the cultivars. In the cv. Tanzania, nitrogen fertilization at the end of the rainy period had beneficial effects only in March when there was an increase in the leaf:stem and leaf:dead plant material ratios. The residual dry matter correlated positively with the height of the forage. The animals grazed 41% of the height of the pasture in the dry period, and 47% in the rainy period.

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Section: Resultsunclassified

Avaliação de três cultivares de Panicum maximum Jacq. sob pastejo: disponibilidade de forragem, altura do resíduo pós-pastejo e participação de folhas, colmos e material morto

Brâncio¹,

Euclides

Júnior³

et al. 2003

R. Bras. Zootec.

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“…Low in this hierarchy of scales is the individual feeding station, at which bite weight and the time budget of grazing can be studied in terms of the interaction between sward structure and bite formation. When the sward structure is homogeneous at the field level, herbage depletion can be viewed as comprising cycles of depletion at the spatial scale of a single feeding station (Ruyle and Dwyer, 1985; Roguet et al ., 1998a). Hence, the relationship between the number of bites removed and the mass removed from a single feeding station is a fundamental element in our understanding of daily intake.…”

Section: Introductionmentioning

confidence: 99%

“…Various studies conducted at the scale of a single feeding station with cattle have shown that cattle have a strong tendency to graze by horizon (Ungar, 1996). Roguet et al . (1998a) found that for sheep, too, the depletion process proceeded in ‘strata’.…”

Section: Introductionmentioning

confidence: 99%

Bite dimensions for cattle grazing herbage at low levels of depletion

Ungar¹,

Ravid²,

Bruckental

2001

Grass and Forage Science

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The processes that occur during the depletion of a single feeding station by grazing cattle are important to our understanding of intake at larger spatial scales. Factorial experiments were conducted in which feeding stations of different sizes were grazed individually by cattle to various levels of depletion, defined as the number of bites removed. Feeding stations in Experiment 1 (alfalfa) measured 0·11, 0·24 and 0·45 m2, and the numbers of bites removed for depletion levels 1–3 were 35, 70 and 104 m−2 respectively. Feeding stations in Experiment 2 (oats) measured 0·11 and 0·24 m2, and the numbers of bites were 45, 95 and 140 m−2 offered. In both experiments a fourth depletion level (not included in the analysis of variance) determined the maximum voluntary depletion, and exceeded 250 bites m−2 offered. Initial sward height was 20 cm. Bite dimensions were derived from the frequency distribution of residual herbage heights. Treatments were replicated over six and four animals of approximately 500 kg live weight in Experiments 1 and 2 respectively. The mean residual herbage height and the frequency distribution of residual heights indicated that bites were removed predominantly from the top grazing horizon at depletion levels 1–3, with a mean effective bite depth of 8·6 cm. Nevertheless, at the same depletion levels, the mean effective bite area declined from 148 to 87 cm2 in Experiment 1 (alfalfa, Medicago sativa L.) and from 86 to 58 cm2 in Experiment 2 (oats, Avena sativa L.). Feeding station size did not significantly affect mean effective bite area in either experiment. Simulation was used to examine the implications of various overlap rules (from completely random to highly systematic) for within‐grazing‐horizon placement of a circular bite of constant potential area. These rules shaped the relationship between mean effective bite area and number of bites removed per unit sward area offered. Bite placement in which permissible overlap became progressively more lenient as the grazing horizon was depleted, and, with acceptable estimates of potential bite area, yielded results that were similar, though not identical, to those measured. These results can help understanding of the factors that determine the intake gain function at a single feeding station.

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“…The design placed emphasis on combinations and balanced sequencing of treatments as opposed to an arrangement with limited number of variables operating at any one time Roguet et al, 1998), and additionally allowed for the investigation of patch carry-over effects. This design provided the opportunity to offer a wide range of choices at a single time and also the opportunity to monitor the cows' willingness to pass over patches in order to acquire the opportunity to graze on a succeeding patch.…”

Section: Linear Arrangementmentioning

confidence: 99%

“…This design provided the opportunity to offer a wide range of choices at a single time and also the opportunity to monitor the cows' willingness to pass over patches in order to acquire the opportunity to graze on a succeeding patch. The design placed emphasis on combinations and balanced sequencing of treatments as opposed to an arrangement with limited number of variables operating at any one time Roguet et al, 1998), and additionally allowed for the investigation of patch carry-over effects. In all three experiments cows were prohibited from turning round, but we do not view this as a limitation of the design as several studies in the literature have noted that large herbivores do not display a marked turning behaviour; rather animals tend to follow a linear trajectory (Senft et al, 1987;Spalinger et al, 1988;Distel et al, 1995).…”

Section: Linear Arrangementmentioning

confidence: 99%

The influence of sward canopy structure on foraging decisions by grazing cattle. I. Patch selection

Griffiths

Hodgson

Arnold

2003

Grass and Forage Science

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Patch selection by grazing dairy cows in response to simultaneous variation in combinations of sward structural characteristics was examined in three experiments in which four mature dairy cows were offered a choice of patches (typically 0.9 m × 0.9 m) of perennial ryegrass (Lolium perenne) presented in a linear arrangement. Treatments involved combinations of variations in sward height, stubble height and/or depth of regrowth, prepared by preliminary cutting treatments. They were arranged in balanced sets of four to nine treatments, which were arranged in linear sequences of eighteen to twenty‐seven patches. Within experiments, sequences were balanced across replicate sets of patches, which were grazed separately by individual cows. The number of bites removed and the residence time for each patch were highly correlated in all three experiments, and the results are reported using number of bites per patch as an estimator of foraging behaviour. In the first experiment, with vegetative swards, cows preferentially selected the tallest swards. When swards comprising reproductive stem were offered in Experiment 2, cows selectively grazed short‐stubble swards rather than tall‐stubble swards, although both offered a similar depth of regrowth. Cows did not exhibit preference for swards comprising the greatest quantity of leaf mass, indicating that the spatial distribution of plant components assumed greater importance. In the third experiment, the number of bites removed increased with increasing depth of regrowth, and was negatively correlated with sward height. The three patch‐appraisal cues investigated were broadly ranked in order of importance as (i) depth of regrowth, (ii) sward maturity and (iii) sward height. There was no evidence, at least at a short temporal scale, that patch behaviour was influenced by conditions in adjacent patches, suggesting that the cows assessed grazing opportunities on a patch‐by‐patch basis.

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Development of a methodology for studying feeding station behaviour of grazing ewes

Cited by 7 publications

References 18 publications

Avaliação de três cultivares de Panicum maximum Jacq. sob pastejo: disponibilidade de forragem, altura do resíduo pós-pastejo e participação de folhas, colmos e material morto

Avaliação de três cultivares de Panicum maximum Jacq. sob pastejo: disponibilidade de forragem, altura do resíduo pós-pastejo e participação de folhas, colmos e material morto

Bite dimensions for cattle grazing herbage at low levels of depletion

The influence of sward canopy structure on foraging decisions by grazing cattle. I. Patch selection

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