Average daily and within-day nycterohemeral patterns of eating and ruminating behavior were determined in six Holstein-Friesian heifers (average BW = 427 kg) given ad libitum access to either corn or grass silage in a two-period crossover design. Rhythm components (number of cycles/24 h) were characterized by finite Fourier transform of the 24-h mastication activities as measured during 4 d by continuous jaw movement recordings. Average daily voluntary intake of corn silage was 8.2% greater (P = .05) than that for grass silage and was associated (P < .05) with fewer meals and shorter daily, unitary eating and ruminating times, and smaller number of rumination boli. Analysis of variance of the daily mean of hourly activities and Rhythm Components 1 to 12 indicated effects of (P < .05) silage type (S), animal (A), period (P), and a significant interaction (S x A x P) for each mastication activity. The finite Fourier transform was reparameterized to express the amplitude (as periodograms) and phase of each rhythm component. Rhythm Components 1, 3, and 4 contributed primarily to explaining the total dispersion of the 24-h series of time spent eating and ruminating, for both silage types and individual heifers. Relative importance of Rhythm Component 1 of time spent eating, indicative of a main circadian pattern, was related positively to pedigree value for milk production (P = .01) and negatively to milk protein concentration (P = .09).(ABSTRACT TRUNCATED AT 250 WORDS)

Does the skull of the sheep behave as a tube or as a complex of independent bones linked by sutures? Is the architecture within cranial bones optimized to local strain alignment? We attempted to answer these questions for the sheep by recording from rosette strain gauges on each frontal and maxillary bone and from single-axis gauges on each dentary of five sheep while they fed on hay. Bone structure was assessed at each rosette gauge site by stereological analysis of high-resolution radiographs. Structural and strain orientations were tested for statistical agreement. Ranges of strain magnitudes were Ϯ1200 ⑀ on the mandible, Ϯ650 ⑀ on the frontals, and Ϯ400 ⑀ on the maxillae. Each gauge site experienced one strain signal when on the working (chewing) side and a different one when on the balancing (nonchewing) side. The two signals differed in mode, magnitude, and orientation. For example, on the working side, maxillary gauges were under mean compressive strains of -132 ⑀ (S.D., 73.3 ⑀), oriented rostroventrally at 25°-70°to the long axis of the skull. On the balancing side, the same gauges were under mean tensile strains of ϩ319 ⑀ (S.D., 193.9 ⑀), at greater than 65°to the cranial axis. Strain patterns on the frontals are consistent with torsion and bending of the whole skull, indicating some degree of tube-like mechanical behavior. Frontal and maxillary strains also showed a degree of individual loading, resulting from modulation of strains across sutures and local effects of muscle activity. The sheep skull seems to behave as a tube made of a complex of independent bones. Structural orientation was in statistically significant agreement with the orientation of working-side compressive principal strain ⑀2, even though principal tensile strains may be as large or larger. Cranial bone architecture in sheep is not optimized to both strain signals it experiences. Anat Rec 264: [325][326][327][328][329][330][331][332][333][334][335][336][337][338] 2001.

Coastal bermudagrass hay was labeled with Cr by the Cr-mordant procedure and with 177Lu applied to the same fiber. Neutral detergent fiber prepared from the same Coastal bermudagrass hay was labeled with Yb, 169Yb, Tb and 160Tb by soaking overnight following by thorough washing and drying. Wood chips were similarly labeled with Sm or La, and Solka Floc was labeled with 147Nd and 141Ce. The carriers, labels and times of administration to cattle were: bermudagrass fiber with both Cr and 177Lu, bermudagrass fiber with 169Yb and Solka Floc labeled with 147Nd at 0 h; bermudagrass fiber with Yb, Solka Floc with 141Ce and wood chips with Sm at 24 h; wood chips with La at 48 h; and bermudagrass fiber labeled with 160Tb at the beginning and labeled with Tb at the end of a meal. Fecal collection followed and passage characteristics were determined with a two-compartment, age-dependent model. Markers labeling the different fiber sources had different (P less than .01) passage rates (Solka Floc greater than Coastal bermudagrass greater than wood chips), but there was no difference within fiber source for rare earth passage. There also was no difference between the passage characteristics of Cr-mordant and 177Lu. However, passage rate of particles administered at the beginning of the meal (160Tb) was 42% higher than for particles at the end of the meal (Tb).(ABSTRACT TRUNCATED AT 250 WORDS)

RESUMO -Os efeitos dos estádios de lactação inicial e final sobre o comportamento e a distribuição nictemeral do comportamento ingestivo foram avaliados com oito vacas leiteiras, consumindo uma dieta à base de silagem de milho. A análise espectral das séries de tempos horários de mastigação (ingestão ou ruminação) foi realizada usando os dados modificados pela transformação finita de Fourier. Foi realizada análise de variância destes dados e a análise dos periodogramas e diagramas de fase. A duração média das refeições e o consumo de matéria seca foram superiores, enquanto o tempo unitário de ruminação foi inferior no período inicial em relação ao final da lactação. A distribuição dos tempos de ingestão e de ruminação nos estádios inicial e final de lactação seguiu, respectivamente, periodicidades de 24, 12, 8 e 4 horas e de 24, 12 e 8 horas. Foi constatado efeito significativo do estádio de lactação para o tempo gasto ingerindo e ruminando no componente de ritmo 4. O estádio da lactação influenciou alguns parâmetros do comportamento ingestivo e sua ritmicidade.Palavras-chave: comportamento ingestivo, estádio de lactação, ritmicidade, vacas leiteiras Ingestive Behavior Nycterohemeral Patterns of Dairy Cows, at the Beginning and at the End of Lactation, Fed a Corn Silage Based DietABSTRACT -The effects of the stage of lactation upon the ingestive behavior nycterohemeral patterns were evaluated with eight dairy cows eating a corn silage based diet. Spectral analysis was performed through application of the finite Fourier transformation upon hourly duration of eating or ruminating time series. Variance analysis and inspection of phase diagrams and periodograms were done upon modified data. The mean meal duration and dry matter intake were larger while the unitary ruminating time was inferior at the beginning than at the end of the lactation. Nycterohemeral patterns of time spent eating or ruminating at the beginning and at the end of lactation followed mainly periodicities of, respectively, 24, 12, 8 and 4 hours and 24, 12 and 8 hours. A significant effect of stage of lactation was observed at the rhythm component 4 for both time spent eating and ruminating. Lactation stage affected some parameters of ingestive behavior and its rhythmicity patterns. . Zootec., v.31, n.5, p.2129-2138, 2002 R. Bras IntroduçãoA ingestão de matéria seca é o principal fator que afeta a performance animal. O gado leiteiro pode modificar o comportamento de acordo com o tipo, quantidade e acessibilidade do alimento e práti-cas de manejo. O conhecimento do comportamento ingestivo do gado leiteiro pode ser utilizado pelos produtores, de modo a aumentar a produtividade e garantir a saúde e longevidade. Como exemplos práticos, poder-se-ia citar a localização de sistemas automáticos de fornecimento de água e alimento, a acessibilidade da ração, a redução da competição entre os animais por espaço, alimento e água, o horário e freqüência de distribuição da ração, entre outros (Albright, 1993).Os ruminantes adaptam-se às diversas condições de al...

1.The eating and ruminatiig activity of four rams given long-chopped silage ad lib. in two daily meals was studied by jaw movement recordings. The events of rumination and pseudo-rumination were observed by fluoroscopy and by cineradiography.2. The rate of eating was highest at the beginning of the main meal and then declined gradually. 3. The silage intake level was low. 4. The swallowed silage did not accumulate at the cardiac region but was forced into the dorsal sac of the rumen by the contractions of the reticulum and cranial sac of the rumen. For regurgitation the solid particles had to return via the ventral and cranial sac of the rumen into the reticulum.5. Liquid reticdar contents with floating solid particles were aspirated into the oesophagus during the maximum of the regurgitation contraction of the reticulum.6. The rumination activity during the day presented a high proportion of pseudo-rumination cycles whereas during the night the ruminatic'n became progressively normal.7. Pseudo-rumination was caused by delayed return of the fibrous silage particles into the reticulum. Thus in pseudo-rumination the regurgI tated material consisted predominantly of fluid containing only a small quantity of solid particles.8. The results explain whi longchopped silage intake is associated with pseudo-rumination, a lower breakdown of particles and a waste of digestion time.Generally it is found that the dry matter (DM) intake of silage is less than that from the original crop fed fresh or in a dried form, the difference being greater with sheep than with cattle (Campling, 1966;Demarquilly, 1973; Dulphy & Michalet, 1975;Demarquilly & Dulphy, 1977; Wilkins, 1978).This lower level of intake could be related partially to the chemical composition of the silage and also to the physical structure of the ensiled forage. Finely chopping the grass before or after ensiling resulted in a significant increase of the DM intake (Dulphy & Demarquilly, 1972, 197:1; Dulphy et af. 1975; Deswysen et af. 1978).With long-v. shortcropped silage, the total eating time was longer. However, the voluntary intake was lower, so that unitary eating time (min/g DM per kg b o d y -~e i g h t~'~~) was significantly greater with long-chopped silage. The measured mean reticulo-rumen particle dimension after it meal of long-chopped silage was greater than with short-chopped silage, so it can be concluded that the chewing activity during intake must be insufficient to reduce the original longer silage particle dimension (Deswysen, 1980). It would be expected that rumination stimuli would be increased by the presence of longer reticulo-rumen particles after feeding long-chopped silage. However, some incomprehensible results were found (Deswysen, 1980): (1) latency time, i.e. period between the end of the main meal and the first rumination period, was increased; (2) the daily ruminating time was shorter, but the unitary ruminating time (min/g DM per kg b o d y -~e i g h t~'~~) was slightly increased; (3) a great nuniber of pseudo-rumination cycles occur...