The timing of grazing bouts (GB) determines how cattle allot time to meet their nutritional needs. Net photosynthesis and evapotranspirational losses increase herbage nonstructural carbohydrate and DM concentrations, which may lead to longer and more intense GB at dusk. Hence, linking the grazing pattern, plant phenology, and herbage allocation time emerges as an option to manipulate the GB and nutrient intake. The objectives of this work were to analyze grazing behavior and performance of beef heifers when herbage allocation was at 0700 each morning (MHA) or at 1500 each afternoon (AHA). Two pairs of experiments were conducted during the winter and spring examining behavior and performance. Measurements were grazing, rumination, and idling times during daylight hours, and their patterns, as well as bite rate, ADG, change in BCS, and daily herbage DMI. In the behavioral experiments, 8 heifers strip-grazed annual ryegrass (Lolium multiflorum Lam.). The grazing, rumination, and idling times as well as bite rate were measured and also analyzed per time of day. In the performance experiments, 48 beef heifers strip-grazed annual ryegrass in 2 groups according to treatments. Daily DMI, ADG, and changes in BCS were analyzed. The AHA increased daily idling time (P < 0.01) and decreased grazing time (P < 0.01). The AHA concentrated grazing time in the evening, when bite rate was greater (P < 0.01). The daylight rumination time varied by time of day (P < 0.01), but total daylight rumination time did not differ (P = 0.11). With AHA, rumination time and idling time were concentrated in the morning and afternoon. In the performance experiment during the winter, there was a treatment x week effect (P < 0.01) for ADG and change in BCS. Beginning in wk 4, heifers in AHA gained 150 g of BW and 0.0145 points of BCS more than those in MHA (P < 0.05) per day. In the spring, AHA increased ADG by 549 g and 0.0145 points of BCS more than those in MHA (P < 0.05) per day during the entire 6 wk. The herbage DMI (kg/d) did not differ in winter (AHA, 5.0 vs. MHA, 4.5) or spring (AHA, 5.6 vs. MHA, 5.0). These results suggest that timing of herbage allocation alters grazing, rumination, and idling patterns; AHA leads to longer and more intense GB when herbage has greater quality, which improves cattle performance.

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El objetivo del trabajo fue evaluar el efecto de la zeolita en una dieta de bovinos en engorde a corral, sobre su performance productiva. En un diseño enteramente al azar y un periodo de 63 días, se utilizaron 129 bovinos Aberdeen Angus, machos castrados, de 14 meses de edad y peso vivo (PV) inicial de 362 kg. Se realizaron 3 tratamientos: 0 gr de Zeolita/animal/día (D0), 50 gr de Zeolita/animal/día (D50) y 100 gr de Zeolita/animal/día (D100). La dieta base fue: silaje de maíz de planta entera 18%, grano de maíz partido 45%, pellets de raicilla de cebada 30%,​pellet de soja 5%, núcleo vitamínico mineral 2%. La cantidad diaria de alimento fue ajustada al 2,5% del PV en base seca. A partir del día 45 se redujo en un 8% el silo y se aumentó en el mismo porcentaje el grano de maíz. Se registró: peso inicial, evolución de peso cada quince días, peso final, y se estimó la ganancia diaria de PV (GDPV). Durante los primeros 30 días se observó un efecto cuadrático (p<0,05)) a favor de D50 sobre GDPV. En la etapa (30-45 días) se verificó un mejor desempeño de D100 corroborado por un efecto lineal (p<0,05) entre 0 y 100 gr. En la etapa (45-60 días), se registró una disminución cuadrática (p<0,05) observándose un mejor comportamiento de GDPV medias (p<0,05) para D0. Por lo tanto, si se hubiese combinado D50 al principio del engorde con D100 al final, cabría esperarse un efecto más claro y favorable de la zeolita.

Abstract:With the purpose of increasing the profitability of milk producers, a pilot study for the production system of veal dairy calves was conducted. This type of rearing is not practiced in our country at present. The study was carried out in the establishment of "cabaña Alicia" dairy farm, located in the district of Magdalena, province of Buenos Aires. 12 Argentinean Holando breed male non-castrated calves were employed for this study, and they were fed on a milk replacer-based liquid diet, to obtain a pale meat as the final product. This kind of meat is characteristic of Europe and also quite widespread throughout this continent. Fortnightly weighting was performed to control the daily body weight gain (DWG). Finally, the calves were slaughtered six months later, with an average DWG 0.73 kg/day, average BW 181 kg, and beef yield 57.6%; blood iron exams at the end of the cycle resulted in average 7.8 gr/dl, considered within the expected parameters to avoid the occurrence of anemia. Thus, we can conclude that this production proposal, compared to traditional artificial calf rearing, is a convenient opportunity to those producers who can enter the market of this kind of meat, or seek consumption sites in our country.

The aim of this study was to evaluate the effect of wheat bran in increasing amounts on the total apparent dry matter digestibility (DM), the fiber (NDF, ADF) and the protein (CP) in goat diets. Eight Criollo x Nubian goats were used in a 4x4 Latin square experimental design. Four diets were provided: alfalfa hay (D 0 ); alfalfa hay + wheat bran (WB) (0.5% of BW/day) (D 1 ), alfalfa hay + WB (1% of BW/day) (D 2 ) and alfalfa hay + WB (1.5% of BW/day) (D 3 ). All the treatments consisted of alfalfa hay delivered ad libitum. In vivo total apparent digestibility of the DM intake and its fractions was calculated as a result of the difference between the ingested and excreted amounts in relation to the intake. Forage intake and the relation forage/concentrate decreased linearly (p < 0.05) with the increase of the concentrate. Energy intake increased linearly (p < 0.05) with larger amounts of WB. The total apparent digestibility of the ingested DM showed a significant linear increase (p < 0.05) with the increase of concentrate. The digestibility of NDF, ADF and CP registered no differences (p > 0.05) with the WB increase in the different treatments. We can conclude that the addition of WB in Criollo x Nubian goats improved the total apparent digestibility of the ingested DM by replacing hay for concentrate, without altering NDF, ADF and CP fractions.