Ernesto Morales-Almaráz

Improving the fatty acid profile of dairy cow milk by combining grazing with feeding of total mixed ration.

Grazing cows could produce milk with a higher proportion of polyunsaturated fatty acids, which is beneficial to human health, compared with non-grazing cows, though grazing alone could compromise milk production. Under oceanic climate conditions, a study involving 15 dairy cows, fed total mixed ration (TMR) ad libitum in combination with different grazing times of 12 h (TMR12), 6 h (TMR06) and zero grazing time (TMR00) with the aim to evaluate different strategies on the fatty acids profile of milk and milk production. No differences were seen between the treatments with respect to milk yield (34.4+/-6.3 kg/d) or milk protein content (30.4+/-1.8 g/kg). The milk produced by the TMR12 cows had less total fat (36.2 vs. 38.2 g/kg) and saturated fatty acid (FA, 69.39 vs. 71.44 g/100 g FA) than that produced by the TMR00 cows. The concentration of vaccenic acid in the TMR06 and TMR12 milk was twice that of the TMR00 milk (4.22, 4.09 and 2.26 g/100 g FA respectively). Linear increases in conjugated linoleic (CLA) and linolenic acids were observed with increasing grazing time. Pasture was an important source of FA especially C18:3 for TMR06 and TMR12 cows. Under oceanic climatic conditions, the grazing of dairy cows as a complement to feeding with TMR can improve the FA profile of milk and increase its CLA content.

In vitro activity of Pithecellobium dulce and Lysiloma acapulcensis on exogenous development stages of sheep gastrointestinal strongyles

An experiment was conducted to evaluate the effects of two lyophilised aqueous extracts of Lysiloma acapulcensis (LAE) and Phitecellobium dulce (PDE) tree leaves on in vitro assessment of hatching of eggs, larval development and migration of gastrointestinal nematodes of sheep using a general linear model. Treatments contained extracts from both species at concentrations of 0, 125, 250 and 500 µg/mL. Both albendazole and levamisole were used at a level of 1% as positive control. The extract of LAE, compared to PDE, showed better inhibition (P<0.05) of egg hatching. Different doses of both the LAE and PDE extracts showed a larvicidal effect (P<0.05) on all larvae exposed to different doses of the extracts. In the larval migration assay, a similar effect with levamisole at doses of 250 and 500 µg/mL occurred with the LAE extract. The extract of P. dulce had a lower larvicidal effect (P<0.05) than levamisole and L. acapulcensis extracts. Using aqueous extracts of both species of L. acapulcensis and P. dulce could be a promising alternative to synthetic anthelmintics as treatments of gastrointestinal nematodes of sheep in organic and conventional production systems under subtropical conditions.

Triaxial accelerometers for recording grazing and ruminating time in dairy cows: An alternative to visual observations

ABSTRACT The aim of this study was to validate the recordings of a commercial triaxial accelerometer (HOBO Pendant G data loggers) with respect to visual observations of grazing and ruminating time of dairy cows. Seven lactating Holstein cows with a mean body weight of 602 ± 45 kg were used for the study. Grazing and ruminating times were recorded using HOBO loggers (31.5 hours of total observations for grazing and ruminating) that were attached to the lateral‐medial side of the jaw using a strap attached to the head of each cow in a position such that the X‐axis was parallel to the ground, the Y‐axis was perpendicular to the ground pointing upward, and the Z‐axis was parallel to the ground pointing away from the sagittal plane; these relative positions were defined when the cow was in a natural head‐up position. Median acceleration (m/s2) readings in the X‐axis >0.175 and <0.95 indicated grazing activity, whereas readings in the Z‐axis >−0.275 and <0.0875 indicated ruminating activity. The degree of vertical tilt (° Y‐axis) was used to determine grazing position (readings >0° and <61°) and ruminating (readings >0° and <25.8°). Results showed a significant (P < 0.001) relationship of estimated grazing time against visual observations when acceleration (X‐axis) was used only; nonetheless acceleration (Z‐axis) was not significant (P > 0.05) for estimating ruminating time. When acceleration and tilt were used for estimating grazing (X‐ and Y‐axis) and ruminating (Z‐ and Y‐axis) time, the slope in both showed a significant (P ≤ 0.001) relationship. The prediction R2 in both activities indicated that acceleration (X‐ and Z‐axis) and tilt (Y‐axis) of HOBO loggers explained 0.961 and 0.945 of the variance in visual observations per cow/day. Therefore, the validation of the HOBO loggers was successful on a per cow/day and per day basis.

Effects of organic chromium supplementation to finishing lambs diet on growth performance, carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium (Cr) to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs (age (4.5±0.2) mon; (25.8±3.6) kg body weight (BW)) were randomly assigned to three levels of supplemental organic Cr (0.0, 0.2 and 0.4 mg kg−1 dry matter (DM)) in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed (contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels (0.2+0.4) ppm Cr). Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased (P<0.05) as organic Cr level increased in the diet. Kidney fat decreased linearly (P<0.05) as supplemental Cr increased. In Longissimus dorsi (LD), the ash content decreased linearly, and shear force (kg cm−2) increased (P<0.05) as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.

Parity and grazing-time effects on milk fatty acid profile in dairy cows

Milk fatty acid (FA) profiles of lactating Holstein dairy cows were determined to evaluate the effects of parity (primiparous or multiparous) and the grazing time (0, 6 and 12 h), complementary to a total mixed ration, in a 2 × 3 factorial design. The interaction of parity with grazing time did not affect milk production and protein content; however, dry matter intake of herbage, total dry matter intake and milk fat content were affected by the interaction (P < 0.05). Both factors affected the milk concentration of monounsaturated FAs. The 18 : 3 cis9 cis12, 18 : 2 cis9 trans11, and 18 : 3 cis9 cis12 cis15 concentrations in milk were higher (P < 0.05) in primiparous cows. Milk 18 : 2 cis9 trans11 concentration in primiparous cows with 12 h grazing (1.17 g/100 g FA) was 44% and 57% higher than with 6 h and 0 h grazing (0.66 and 0.50 g/100 g FA, respectively). Similar pattern was observed for 18 : 3 cis9 cis12 cis15. The milk 18 : 1 trans11 concentration was higher (P < 0.05) with 6 h and 12 h grazing than without grazing. In conclusion, the parity would appear to mainly affect the proportion of short-chain FAs, and had an important influence on the proportions of 18 : 2 cis9 trans11, and 18 : 3 cis9 cis12 cis15. These FAs and also 18 : 1 trans11 were modified by grazing time.

Mineral Status and Interrelationship in Soil, Forage, and Blood Serum of Horses in the Rainy and Dry Seasons

Abstract The objective was to evaluate the content of P, Ca, Mg, K, Na, Cu, Fe, Zn, Se, and Mn in soil, forage, and serum of horses in several production units (PU) during rainy and dry seasons and predict their concentration in serum from their content in soil and forage. Soil and pastures were sampled in the dry (November–December) and in rainy seasons (June–July), and blood samples were collected from the jugular vein of 76 horses in both seasons at four PU. The experimental design was a completely random design within a 4 × 2 (PU × season) factorial arrangement of treatments. Concentration of minerals in soil differed (P < .05) among PU, and contents of P, Ca, Mg, and K were low; Zn and Fe were high; and Cu and Mn were adequate. Mineral concentrations in forage differed among PU and season, and among PU within season (interaction P < .05). Contents of Ca, Mg, Na, Zn, and Cu were low; Fe was high; and P, K, Se, and Mn adequate. The mineral concentration in equine blood serum differed (P < .05) among PU and season. Overall, there were deficiencies of P, Ca, Mg, Na, Cu, and Se, but adequate amounts of K, Zn, and Fe. There are imbalances of minerals in soil and forages which effected their concentration inequine blood. HighlightsConcentrations of P, Ca, Mg, Na, Cu, and Se were deficiency in equine serum.Equine serum has adequate amounts of K, Zn, and Fe.Higher regression effect (R2 = 0.97) in serum iron with forage.Lower regression effect (R2 = 0.54) in serum copper with forage.