Selectivity of ewes grazing on wheat stubble

A study was carried out for 61 days in order to evaluate the selectivity of ewes grazing on wheat stubble with and without a supplement to correct nutritional deficiency. The supplement was offered at a rate of 0.45 kg per ewe per day, composed of: 46.5% oats, 6% fishmeal, 47% rape meal and 0.5 % of minerals. A field of 17.14 hectares of wheat stubble, and 120 Romney Marsh ewes were used. The experimental design was a randomized block, with 60 ewes per treatment. Feces of six ewes per treatment, at the beginning, middle and the end of the experiment were collected in order to make a histological analysis of the relative presence (%) of vegetal species of the stubble consumed by the ewes. Chemical analysis of the stubble was made in order to determine content of total protein (PT), ADF , lignine, ash, N, P, K, Mg, Ca, Mn and Fe. The ewes showed a high selectivity to the species in order to balance the daily ration and great ability to encounter Echium vulgare and Rubus ulmifolius, species with high protein and mineral content. There was no significant difference of selectivity between treatments (P> 0.05), but there was a significant difference between periods (P<0.05). The protein content rate of vegetal species ranged between 4.3 and 22.6 % on a dry matter basis. The following percentages were found in feces: wheat stubble 29.65 % and 26.76 %; Echium 23.62 % and 23.38 %; and Rubus 21.55 % and 28.99% on treatments with and without supplementation, respectively. RESUMEN Se realizó un estudio durante 61 días, con el objeto de evaluar la selectividad de los ovinos cuando se utiliza rastrojo de trigo como único alimento, y cuando se mejora la ración diaria de los ovinos con un concentrado, que corrija en parte las deficiencias de la paja de trigo. El concentrado se suministró a razón de 0,45 kg oveja-1 día-1 y contenía 46,5% avena grano, 6% harina de pescado, 47% afrecho de raps y 0,5% de sales minerales. Se utilizaron 17,14 ha de rastrojo de trigo y 120 ovinos Romney Marsh. El diseño empleado fue bloques completamente al azar, con 60 animales por tratamiento. Se muestrearon fecas en seis ovejas por tratamiento al inicio, mitad y final del experimento, se sometieron a análisis histológico para a determinar la presencia relativa de las especies componentes del rastrojo consumidas por los ovinos. Se efectuaron análisis químico de los componentes del rastrojo para proteína total (PT), fibra detergente ácido (FDA), lignina, cenizas, N, P, K, Mg, Ca, Mn, y Fe. Las ovejas mostraron un alta selectividad de las especies para formular su dieta diaria, y gran habilidad para consumir hierba azul y zarzamora, especies que presentan un evado tenor proteico y mineral. La selectividad no difirió significativamente entre tratamientos (P>0,05), pero si entre períodos (P<0,05). Los rangos de contenido de proteína de las especies fluctuaron entre 4,3 y 22,6% base materia seca. Se observó en las fecas predominancia de paja de trigo 29,65% y 26,76%, seguida de hierba azul 23,62% y 23,38%, y zarzamora 21,55% y 28,99%, en los tratamientos sin suplemento y con suplementación, respectivamente

Effects of Sugar Beet Silage, High-Moisture Corn, and Corn Silage Feed Supplementation on the Performance of Dairy Cows with Restricted Daily Access to Pasture

A study was undertaken to assess the effect of supplementation with sugar beet silage, corn silage, or high-moisture corn on dairy performance, rumen, and plasma metabolites in dairy cows under conditions of restricted grazing in spring. Eighteen multiparous Holstein Friesian cows, stratified for milk yield (39.4 kg/day &plusmn; 3.00), days of lactation (67.0 days &plusmn; 22.5), live weight (584 kg &plusmn; 38.0), and number of calves (5.0 &plusmn; 1.5), were allocated in a replicated 3 &times; 3 Latin square design. Treatments were as follows: SBS (10 kg DM of permanent pasture, 7 kg DM of sugar beet silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement); corn silage (10 kg DM of permanent pasture, 7 kg DM of corn silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement), and HMC (10 kg DM of permanent pasture, 5 kg DM of high-moisture corn, 4.5 kg DM of concentrate, 1.2 kg DM of pasture silage, 0.21 kg of mineral supplement). Pasture was offered rotationally from 9 a.m. to 4 p.m. Between afternoon and morning milking, the cows were housed receiving a partial mixed ration and water ad libitum. The effect of treatments on milk production, milk composition, body weight, rumen function, and blood parameters were analyzed using a linear&ndash;mixed model. Pasture dry matter intake (DMI) was lower in SBS than CS (p &lt; 0.05) and similar to HMC, but total DMI was higher in HMC than SBS (p &lt; 0.05) and similar to CS. Milk production for treatments (32.6, 31.7, and 33.4 kg/cow/day for SBS, CS, and HMC, respectively), live weight, and fat concentration were not modified by treatments, but milk protein concentration was lower for SBS compared with HMC (p &lt; 0.05) and similar to CS. B-hydroxybutyrate, cholesterol, and albumin were not different among treatments (p &gt; 0.05), while urea was higher in SBS, medium in CS silage, and lower in HMC (p &lt; 0.001). Ruminal pH and the total VFA concentrations were not modified by treatments (p &gt; 0.05), which averaged 6.45 and 102.03 mmol/L, respectively. However, an interaction was observed for total VFA concentration between treatment and sampling time (p &lt; 0.05), showing that HMC produced more VFA at 10:00 p.m. compared with the other treatments. To conclude, the supplementation with sugar beet silage allowed a milk response and composition similar to corn silage and HMC, but with a lower concentration of milk protein than HMC. In addition, sugar beet silage can be used as an alternative supplement for high-producing dairy cows with restricted access to grazing during spring

Pre-grazing herbage mass affects grazing behavior, herbage disappearance, and the residual nutritive value of a pasture during the first grazing session

CONICYT-PCHA programm

The timing of pasture allocation and grass silage supplementation affect pasture intake, milk production and nitrogen partitioning of dairy cows

Aim of study: To evaluate the effect of time of pasture allocation (PA) and grass silage allocation on dry matter (DM) intake, grazing behaviour, milk production, rumen function and N partitioning of grazing dairy cows. Area of study: Valdivia, Chile Material and methods: Forty-five Holstein-Friesian cows were selected from the Austral Agricultural Research Station at the Universidad Austral de Chile. Cows were allocated to one of three treatments: MPA: 75% of PA and 25% of the silage allowance allocated in the morning; BPA: 50% of PA and silage allowance allocated in the morning; APA: 25% of the PA and 75% of the silage allowance allocated in the morning. All treatments received the complement of pasture and silage allowance in the afternoon. Cows received a daily PA of 21 kg dry DM, 3 kg DM of grass silage and 3.5 kg DM of concentrate. Main results: Grazing time was not affected by treatments, however, grazing time between afternoon-morning milking was longer for APA. DM intake and milk production were not modified by treatments, averaging 15.6 kg DM/cow and 22.7 kg milk/d, respectively. Rumen propionate was greater for BPA than APA (18.8 and 17.7 mmol/100 mol, respectively). N intake and N excretion throughout milk, urine and feces were not modified by treatments, averaging 458, 119, 195 and 144 g N/d, respectively. Research highlights: The combination of time of pasture and grass silage allocation is not an adequate strategy to modify pasture intake, milk production and N excretion in dairy cows

The L-[alpha]-lysophosphatidylinositol/GPR55 system and its potential role in human obesity

GPR55 is a putative cannabinoid receptor, and l-α-lysophosphatidylinositol (LPI) is its only known endogenous ligand. We investigated 1) whether GPR55 is expressed in fat and liver; 2) the correlation of both GPR55 and LPI with several metabolic parameters; and 3) the actions of LPI on human adipocytes. We analyzed CB1, CB2, and GPR55 gene expression and circulating LPI levels in two independent cohorts of obese and lean subjects, with both normal or impaired glucose tolerance and type 2 diabetes. Ex vivo experiments were used to measure intracellular calcium and lipid accumulation. GPR55 levels were augmented in the adipose tissue of obese subjects and further so in obese patients with type 2 diabetes when compared with nonobese subjects. Visceral adipose tissue GPR55 correlated positively with weight, BMI, and percent fat mass, particularly in women. Hepatic GPR55 gene expression was similar in obese and type 2 diabetic subjects. Circulating LPI levels were increased in obese patients and correlated with fat percentage and BMI in women. LPI increased the expression of lipogenic genes in visceral adipose tissue explants and intracellular calcium in differentiated visceral adipocytes. These findings indicate that the LPI/GPR55 system is positively associated with obesity in humans