RESUMO

Traditional knowledge about the behavior of grazing livestock is about to disappear. Shepherds well know that sheep behavior follows non-random patterns. As a novel alternative to seeking behavioral patterns, this study quantified the grazing activities of two sheep flocks of Churra breed (both in the same area but separated by 10 years) based on Global Position System (GPS) monitoring and remote monitoring sensing techniques. In the first monitoring period (2009-10), geolocations were recorded every 5 min (4,240 records), while in the second one (2018-20), records were taken every 30 min (7,636 records). The data were clustered based on the day/night and the activity (resting, moving, or grazing). An airborne LiDAR dataset was used to study the slope, aspect, and vegetation height. Four visible-infrared orthophotographs were mosaicked and classified to obtain the land use/land cover (LU/LC) map. Then, GPS locations were overlain on the terrain features, and a Chi-square test evaluated the relationships between locations and terrain features. Three spatial statistics (directional distribution, Kernel density, and Hot Spot analysis) were also calculated. Results in both monitoring periods suggested that the spatial distribution of free-grazing ewes was non-random. The flocks showed strong preferences for grazing areas with gentle north-facing slopes, where the herbaceous layer formed by pasture predominates. The geostatistical analyses of the sheep locations corroborated those preferences. Geotechnologies have emerged as a potent tool to demonstrate the influence of environmental and terrain attributes on the non-random spatial behavior of grazing sheep.

Assuntos

RESUMO

This study aimed to evaluate the behavior of sheep fed babassu cake as a substitution for elephant grass silage. The experiment was conducted at the Federal Rural University of Amazonia (Universidade Federal Rural da Amazônia - UFRA), Brazil, using 45 sheep housed in individual stalls, with unlimited access to feed and distributed in a completely randomized design with five treatments (0, 12.5, 25, 37.5 and 50% inclusion of babassu cake) and nine replications. All of the treatments contained a roughage-to-concentrate ratio of 40:60. No differences were observed in the time spent feeding (P > 0.05), regardless of the source of roughage used. However, there was a reduction in the time spent in rumination (P < 0.05) and an increase in time spent idling (P < 0.05) when babassu cake was included in the diet. Although there was a reduction in the time spent chewing the ruminal bolus (P < 0.05), the total daily chewing time was the same for all animals (P > 0.05). However, the sheep fed babassu cake showed higher feeding and rumination efficiency (P < 0.05). Therefore, the substitution of elephant grass silage with babassu cake can be performed at up to 50% without compromising the total time spent eating and chewing, which allows increased feeding and rumination efficiency.

Assuntos

RESUMO

Invasion by exotic grasses is a severe threat to the integrity of grassland ecosystems all over the world. Because grasslands are typically grazed by livestock and wildlife, the invasion is a community process modulated by herbivory. We hypothesized that the invasion of native South American grasslands by Eragrostis plana Nees, an exotic tussock-forming grass from Africa, could be deterred by grazing if grazers switched dietary preferences and included the invasive grass as a large proportion of their diets. Bos taurus (heifers) and Ovis aries (ewes) grazed plots with varying degrees of invasion by E. plana in a replicated manipulative experiment. Animal positions and species grazed were observed every minute in 45-min grazing session. Proportion of bites and steps in and out of E. plana tussocks were measured and used to calculate several indices of selectivity. Both heifers and ewes exhibited increasing probability of grazing E. plana as the proportion of area covered by tussocks increased, but they behaved differently. In agreement with expectations based on the allometry of dietary preferences and morphology, ewes consumed a low proportion of E. plana, except in areas that had more than 90% E. plana cover. Heifers consumed proportionally more E. plana than ewes. Contrary to our hypothesis, herbivores did not exhibit dietary switching towards the invasive grass. Moreover, they exhibited avoidance of the invasive grass and preference for short-statured native species, both of which should tend to enhance invasion. Unless invasive plants are highly palatable to livestock, the effect of grazing to deter the invasion is limited, due to the inherent avoidance of the invasive grass by the main grazers in the ecosystem, particularly sheep.

Assuntos

RESUMO

Sheep have been suggested to use their senses to perceive plant properties and associate their intake with consequences after ingestion. However, sheep with browsing experience do not seem to select against tannin-rich browsing materials in cafeteria trials. Thus, the objective of the present study was to evaluate the relationship between the chemical composition, selectivity index (SI), preference and intake rate (IR) of tannin-containing forage trees offered to sheep in cafeteria experiments. Four trees were selected for their condensed tannin content and their varying biological activities. Havardia albicans (high biological activity), Leucaena leucocephala (medium biological activity), Acacia gaumeri (low biological activity) and Brosimum alicastrum (very low biological activity) were used in this study. Ten hair sheep (23.7kg±1.43LW) with eight months of browsing experience in native vegetation were used in this study. Polyethylene glycol (PEG 3600MW) was administered to five sheep during all experiments. In experiment 1, fresh foliage from all trees was offered ad libitum for 4h. In experiment 2, B. alicastrum was withdrawn and the preference was determined again. The forage preference in experiment 1 was A. gaumeri (14.77gDM/kgLW)>B. alicastrum (11.77gDM/kgLW)>H. albicans (3.71gDM/kgLW)=L. leucocephala (1.87gDM/kgLW) (P<0.05). The preference in experiment 2 was A. gaumeri>H. albicans=L. leucocephala. PEG administration had no effect on the preference or IR. The intake rate seemed to have been affected by the plant density. Moreover, fiber compounds were found to be better predictors of DM intake than polyphenolic compounds at levels typically found in the evaluated forages. It was concluded that tannins and PEG did not modify the preferences of sheep in cafeteria trials. Thus, tannins are not involved in the preference regulation of animals with browsing experience.

Assuntos

RESUMO

The experiment evaluated the effects of strategic shearing on feeding behavior in Ile de France ewes in Bermudagrass (Cynodon dactylon) grazing during breeding season. A total of 20 ewes, female, Ile de France breed, 4 years old, 71.10 kg of body weight, in grazing, in a completely randomized design with two treatments and ten repetitions, in which the treatments were composed by shorn and non-shorn animals. The length of the breeding season was 90 days, where the evaluations occurred in the 86th, 87th and 88th day of the experimental period. The grazing time (6.50 hours), rumination (1.59 hours) and idle (3.97 hours) have not changed (P> 0.05) by strategic shearing of the animals, as well as the frequency and the time by frequency grazing (18.33 grazing and 21.49 min/grazing), rumination (10.71 ruminations and 8.83 min/rumination) and idle (18.83 idles and 12.66 min/idle). In the same way, the number of bits per minute (26.37 bits) and the total daily bits (19.116 bits) of the animals were not affected. Thus, the strategic shearing in Ile de France ewes in Bermudagrass grazing during the breeding season does not alter animal feeding behavior.(AU)

O experimento foi conduzido com o objetivo de avaliar o efeito da tosquia estratégica no comportamento ingestivo de ovelhas Ile de France em pastagem de capim vaquero (Cynodon dactylon) durante a estação de monta. Foram utilizados 20 ovinos, fêmea, da raça Ile de France, com idade média de 4 anos, e peso corporal médio de 71,10 kg, em pastejo, em delineamento experimental inteiramente casualizado, com dois tratamentos e dez repetições, em que os tratamentos foram constituídos de ovelhas tosquiadas e não tosquiadas. A duração da estação de monta foi de 90 dias, sendo que as avaliações ocorreram nos 86, 87 e 88º dia do período experimental. O tempo de pastejo (6,50 horas), ruminação (1,59 horas) e ócio (3,97 horas) não foram alterados (P>0,05) pela tosquia estratégica dos animais, assim como a frequência e o tempo por frequência de pastejo (18,33 pastejos e 21,49 min/pastejo), ruminação (10,71 ruminações e 8,83 min/ruminação) e ócio (18,83 ócios e 12,66 min/ócio). Da mesma forma, a quantidade de bocados por minuto (26,37 bocados) e o total de bocados diário (19.116 bocados) dos animais não foram afetados. Sendo assim, a tosquia estratégica em ovelhas Ile de France em pastagem de capim vaquero durante a estação de monta não altera o comportamento ingestivo dos animais.(AU)

Assuntos

RESUMO

The experiment evaluated the effects of strategic shearing on feeding behavior in Ile de France ewes in Bermudagrass (Cynodon dactylon) grazing during breeding season. A total of 20 ewes, female, Ile de France breed, 4 years old, 71.10 kg of body weight, in grazing, in a completely randomized design with two treatments and ten repetitions, in which the treatments were composed by shorn and non-shorn animals. The length of the breeding season was 90 days, where the evaluations occurred in the 86th, 87th and 88th day of the experimental period. The grazing time (6.50 hours), rumination (1.59 hours) and idle (3.97 hours) have not changed (P> 0.05) by strategic shearing of the animals, as well as the frequency and the time by frequency grazing (18.33 grazing and 21.49 min/grazing), rumination (10.71 ruminations and 8.83 min/rumination) and idle (18.83 idles and 12.66 min/idle). In the same way, the number of bits per minute (26.37 bits) and the total daily bits (19.116 bits) of the animals were not affected. Thus, the strategic shearing in Ile de France ewes in Bermudagrass grazing during the breeding season does not alter animal feeding behavior.

O experimento foi conduzido com o objetivo de avaliar o efeito da tosquia estratégica no comportamento ingestivo de ovelhas Ile de France em pastagem de capim vaquero (Cynodon dactylon) durante a estação de monta. Foram utilizados 20 ovinos, fêmea, da raça Ile de France, com idade média de 4 anos, e peso corporal médio de 71,10 kg, em pastejo, em delineamento experimental inteiramente casualizado, com dois tratamentos e dez repetições, em que os tratamentos foram constituídos de ovelhas tosquiadas e não tosquiadas. A duração da estação de monta foi de 90 dias, sendo que as avaliações ocorreram nos 86, 87 e 88º dia do período experimental. O tempo de pastejo (6,50 horas), ruminação (1,59 horas) e ócio (3,97 horas) não foram alterados (P>0,05) pela tosquia estratégica dos animais, assim como a frequência e o tempo por frequência de pastejo (18,33 pastejos e 21,49 min/pastejo), ruminação (10,71 ruminações e 8,83 min/ruminação) e ócio (18,83 ócios e 12,66 min/ócio). Da mesma forma, a quantidade de bocados por minuto (26,37 bocados) e o total de bocados diário (19.116 bocados) dos animais não foram afetados. Sendo assim, a tosquia estratégica em ovelhas Ile de France em pastagem de capim vaquero durante a estação de monta não altera o comportamento ingestivo dos animais.

Assuntos

RESUMO

The establishment and maintenance of individual social status is a stressor that affects negatively the reproductive function. Therefore, the aims of this study were to determine if after grouping two unknown rams there is a stress response, and their sexual behavior is affected, and if those responses differ between the rams that resulted dominants and those that resulted subordinates. Twelve adult rams were maintained in individual pens for one month, and on Day 0, hour 0 two rams of similar body weight were grouped in a neutral pen. Social rank was determined using the food competition test, in which each pair of rams was allowed to compete for feed in a bucket only large enough for one of them; the ram that was able to eat from the bucket for more than 1 min, was considered to be the dominant individual. Cortisol concentrations were measured on Day 0 during the first 12h after grouping. Testosterone concentrations were measured from Day -9 to Day 16. Sexual behavior of rams toward estrus ewes was determined before and after grouping in individual pen tests. There was no difference between dominant and subordinated rams in none of the studied variables. Cortisol concentration had a peak 30 min after grouping the rams (P<0.0001). There was a significant decrease in testosterone concentration on Day 5 and Days 8-14 compared to concentration before grouping (P=0.02). The frequency of ano-genital sniffing and flehmen of estrus ewes decreased after grouping, with no differences between dominant and subordinated rams (P=0.009 and 0.03 ano-genital sniffing and flehmen, respectively). However, the frequency of lateral approaches (P=0.005), and all mating behaviors towards ewes increased after grouping the rams (mount attempts: P=0.02; mounts: P=0.008; mounts with ejaculation: P=0.05; total mounts: P=0.003; ejaculation/total mounts: P=0.0004). It was concluded that grouping unknown rams modified their sexual strategy resulting in an increase in the number of mating behaviors when rams were tested alone with estrus ewes. However, grouping two unfamiliar rams was a stressful event that negatively affected testosterone concentrations but the stress and behavior responses did not differ according to rams' social rank.

Assuntos

RESUMO

Intake induction refers to the phenomenon by which animals increase consumption of a less-valued meal when followed by a highly-preferred food relative to when followed by no food or by the same less-preferred food. In the Training phase of the present experiment, we assessed the induction effect in sheep using a within-subject design where learning could be tested while controlling for digestive state. Results showed that, once intake reached stability, subjects ate more low-nutritious food (oat hay) when followed than when preceded by a preferred food (soybean meal), supporting the learning hypothesis of induction. The objective of the second, Revaluation, phase of the experiment was to explore the associative mechanism of induction, for which we paired gastrointestinal malaise caused by lithium chloride intoxication with consumption of soybean meal or a control food (wheat bran). Despite subjects partially rejecting soybean meal relative to controls after the aversive conditioning protocol, oat hay consumption seemed unaffected by soybean meal devaluation. We conclude that intake induction in sheep may rely on changes in hedonic properties of the low-nutritious food based on its association with post-ingestive feedback from the preferred food (hedonic hypothesis), but not on an explicit anticipation of the latter (signalling hypothesis).

Assuntos

RESUMO

A group of 19 Merino rams was used to determine: (i) if body weight, age and testis characteristics are different between high (HR) and low-ranked (LR) rams, and (ii) how the competition between HR and LR rams for oestrous ewes affect their courtship and mating behaviour. Hierarchy was determined using the food competition test. The five first and five last ranked rams were individually exposed to oestrous ewes in pen tests, and the frequency of different courtship behavioural units, mounts and mates, and the time from test onset to each mate was recorded. The sexual behaviour of the five first ranked and the five last ranked rams was also tested in competition, pairing a HR and a LR ram. Age, body weight, body condition score, scrotal circumference, and testis firmness and resilience from HR and LR were not different. The display of courtship behavioural units was lower when rams were tested in competition but was not affected by the rank of the rams. The number of mates per test from HR rams was lower than that observed in LR rams when tested alone. While the number of mates decreased in LR rams in competition tests, it was not affected in HR rams. In summary, there was no relation between social rank and body weight, age or testis characteristics. LR rams were more effective than HR rams when mating oestrous ewes without competition. However, in competitive tests, although all rams modified their courtship strategies, LR rams were more affected by the presence of dominant rams than HR rams were by the presence of LR rams.

Assuntos