Maternal n-6 and n-3 fatty acid status during pregnancy is related to infant heart rate and heart rate variability: An exploratory study.

Early life heart rate (HR) and heart rate variability (HRV) reflect autonomic system maturation. Intervention with n-3 long chain polyunsaturated fatty acids (LCPUFAs) during pregnancy favorably affects fetal HR and HRV, complementing previous observations for n-3 LCPUFA intervention during infancy. The relationship between maternal fatty acid status during pregnancy and infant HR/HRV has not previously been assessed. The aim of this study was to explore associations between maternal n-6 and n-3 fatty acid status during pregnancy and infant HR and HRV at 2 weeks, 4 months, and 6 months of age using linear regression models. Maternal n-3 fatty acids were inversely related to infant HR and positively related to HRV. Conversely, maternal n-6 fatty acids were positively related to infant HR and inversely related to HRV. These data build on existing literature evidencing a role for n-3 fatty acids in accelerating autonomic development and link n-6 fatty acids to HR/HRV.

Gastrointestinal nematode infection and performance of weaned stocker calves in response to anthelmintic control strategies.

Gastrointestinal nematode (GIN) parasite control recommendations are in a state of flux because of the increase in anthelmintic resistant cattle parasites, such as Cooperia spp. In addition, Cooperia spp. infection is typically high in warm-season grass pastures and can affect growth performance of grazing stocker calves in the Gulf Coast Region. This study evaluated the effects of moxidectin pour-on, oxfendazole oral suspension, or a combination of the two given at separate times on infection and performance of weaned beef calves grazing summer forages. Steers (n=42) and heifers (n=31) were stratified by sex, d-11 fecal egg count (FEC), and d-1 shrunk body weight (BW) to one of 10 pastures with four anthelmintic treatments and one control. Treatments included: (1) oxfendazole given on d 0 and moxidectin on d 73 (O+M), (2) moxidectin given on d 0 and oxfendazole on d 73 (M+O), (3) moxidectin given on d 0 (M), (4) oxfendazole given on d 0 (O) and (5) no anthelmintic given (CON). Calves grazed for d-110 beginning May 27th. Response variables were FEC (collected on d-11, 14, 31, 45, 59, 73, 87 and 108), coprocultures (evaluated for d 87 and 108), final shrunk BW, shrunk BW gain, average daily gain (ADG), and full BW gain (collected on d 31, 59, 73, 87, and 108). Calves treated with either oxfendazole (O+M and O) or moxidectin (M+O and M) on d 0 had significantly lower (P<0.001) FEC than the CON calves on d 14, 31 and 45. However, the M+O treated calves had significantly higher (P<0.001) FEC than both oxfendazole treated groups. In addition, calves treated with a second dewormer on d 73 (O+M and M+O) had significantly lower (P<0.001) FEC by d 87 than the CON or M treated calves. Shrunk BW gain and ADG were significantly greater (P=0.005) for the O+M compared to the M treated and CON calves, but comparable with the M+O and O treated calves, respectively. Coprocultures sampled on d 87 and 108 for calves not receiving a second dewormer were predominantly Cooperia spp. and Ostertagia spp. On d 87, no larvae were recovered from the M+O treated calves, whereas the O+M treated calves had 94% Cooperia spp. and 3% Ostertagia spp. recovered. Providing a benzimidazole with a macrocyclic lactone given at two different periods may provide better GIN parasite control and improve animal gains for stocker calves grazing warm-season grass pastures.

Prediction of swine carcass composition by total body electrical conductivity (TOBEC).

An experiment was conducted to determine prediction equations that used readings for total body electrical conductivity (TOBEC) in the model for estimation of total fat-free lean and total fat weight in the pork carcass. Ultrasound measurements of live hogs were used to select 32 gilts that represented a range in weight, muscling, and fatness. The TOBEC readings were recorded on warm carcass sides, chilled carcass sides, and the untrimmed ham from the left carcass side. Physical dissection and chemical analyses determined fat-free lean and fat weight of the carcass. All of the ham tissues were analyzed separately from the remainder of the carcass tissues to incorporate ham measurements for prediction of total fat-free lean and total fat weight in the entire carcass. Prediction equations were developed using stepwise regression procedures. An equation that used a warm carcass TOBEC reading in the model was determined to be the best warm TOBEC equation (R2 = 0.91; root mean square error = 0.81). A three-variable equation that used chilled carcass TOBEC reading, chilled carcass temperature, and carcass length in the model was determined to be the best chilled TOBEC equation (R2 = 0.93; root mean square error = 0.73). A four-variable equation that included chilled carcass side weight, untrimmed ham TOBEC reading, ham temperature, and fat thickness beneath the butt face of the ham in the model was determined to be the best equation overall (R2 = 0.95; root mean square error = 0.65). The TOBEC and the fat-free lean weight of the ham are excellent predictors of total carcass fat-free lean weight.

Effects of Postmortem time of calcium chloride injection on beef tenderness and drip, cooking, and total loss.

The effect of postmortem time of calcium chloride (CaCl(2)) injection in conjunction with postmortem aging was determined on 16 beef semimembranosus muscles. Each muscle was cut into four equal segments that were randomly assigned: (1) no injection (control); (2) CaCl(2) at 1 h postmortem; (3) CaCl(2) at 12 h postmortem; or (4) CaCl(2) at 24 h postmortem. Samples were injected with a 0·3 m solution of CaCl(2) at 10% by weight. At 24 h postmortem, each segment was divided into two pieces that were randomly assigned to either a 10-day aging period (2°C) or to frozen storage (-29°C). Shear force values were higher (P < 0·01) in control samples compared with injected samples and increased linearly (P < 0·05) with time of injection. Drip loss was lower (P < 0·01) in control samples compared with injected samples. A linear (P < 0·05) effect was found for the increases in cooking and total loss due to injection time. Aging decreased (P < 0·05) shear force values and cooking loss. CaCl(2) injection at 1 h postmortem was most effective in reducing shear force values and preventing excessive moisture loss. However, injection at 12 or 24 h postmortem was also effective in lowering shear force values.