Effect of pre-shipment preconditioning and injectable antioxidant trace elements (Cu, Mn, Se, Zn) and vitamins (A, E) on plasma metabolite and hormone concentrations and growth in weaned beef cattle

Weaning and transport represent a high stress time for calves. Preconditioning (PC) by weaning before the transport separate these stressors. The stressors generate oxidative stress, which can be reduced by mineral and vitamin supplementation (MVS) with an antioxidant capacity. Our objective was to evaluate the effect of PC and MVS on performance of steers. The experiment used a 2 × 2 factorial arrangement design, considering a 26-d PC treatment from weaning to transport to the feedlot (d 0); and injectable MVS on d -45, -26, and 0. The MVS consisted of Cu, Zn, Mn, Se, vitamin E (0.2, 0.8, 0.2, 0.1, and 1 mg/kg body weight (BW), respectively), and vitamin A (1190 IU/kg). Sixty Angus-crossbred steers (186.4 ± 27.6 kg) were randomly assigned to the four treatments (MVS+PC; N+PC; MVS+N; N+N; n = 15/treatment). Body weight (BW) was recorded on d -45, -26, 0, 8, 15, and 29. On d 0, an additional BW was taken 30 minutes after the 5-hour transportation (d 0.5). Between d 0 to 29, dry matter intake (DMI) and average daily gain (ADG) to DMI ratio (G:F) were measured. Between d -26 to 29 plasma concentrations of glucose, free fatty acids (NEFA), cortisol, insulin, total antioxidant status (TAS), and thiobarbituric acid-reactive substances (TBARS) were evaluated. Data were analyzed using the MIXED procedure of SAS with repeated measures, using treatment, time, and treatment × time as fixed effects, and steer as a random effect. Between d -26 to 0, there was an interaction of MVS × PC (P ˂ 0.01) for ADG. From d -26 to 0, N+N and N+PC had the greatest and lesser ADG, respectively. On d 0.5, no-PC steers tended to lose BW while the PC steers tended to gain BW (P = 0.09). In the period d 0 to 8, there were no differences (P ≥ 0.27) in DMI, but the PC steers had greater G:F and ADG (P < 0.01) compared with no-PC steers. Plasma NEFA concentration on d 0 was affected by MVS×PC (P < 0.01), because MVS decreased plasma NEFA concentration in no-PC steers, but it increased in the PC steers. Plasma concentrations of glucose, insulin, and cortisol did not differ among treatments (P ≥ 0.23). There was a MVS×PC interaction (P = 0.09) for TAS on d 0; N+N had the greatest and MVS+N had the lowest TAS concentrations. In conclusion, a 26-d PC decreased steers BW compared with no-PC steers. The BW loss during preconditioning was not recovered 29-d after feedlot entry. Despite this BW loss, MVS treatment decreased BW loss in the steers allocated to PC treatment on the day of transport.

Mid-Infrared Spectroscopic Analysis of Raw Milk to Predict the Blood Plasma Non-Esterified Fatty Acid Concentration in Dairy Cows

ABSTRACTIn high yielding dairy cattle, severe postpartum negative energy status is often associated with metabolic and infectious disorders that negatively affect production, fertility and welfare. Mobilization of adipose tissue associated with a negative energy status is reflected through an increased level of non-esterified fatty acids (NEFA) in the blood plasma. Earlier, identification of a negative energy status through the detection of increased blood plasma NEFA concentration required laborious and stressful blood sampling. More recently there have been attempts to predict blood NEFA concentration from milk samples. This study aimed to develop and validate a model to predict the blood plasma NEFA concentration using milk mid-infrared (MIR) spectra that are routinely measured in the context of milk recording. To this end, blood plasma and milk samples were collected in weeks 2, 3 and 20 post-partum for 192 lactations in 3 different herds. The blood plasma samples were taken in the morning, while representative milk samples were collected during the morning and evening milk session on the same day. To predict the blood plasma NEFA concentration from the milk MIR spectra, partial least squares regression models were trained on part of the observations from the first herd. The models were then thoroughly validated on all other observations of the first herd and on the observations of the two independent herds to explore their robustness and wide applicability. The final model can accurately predict blood plasma NEFA concentrations below 0.6 mmol/L with a root mean square error of prediction (RMSE) of less than 0.143 mmol/L. However, for blood plasma with more than 1.2 mmol/L NEFA, the model clearly underestimates the true level. Additionally, it was found that morning blood plasma NEFA levels were predicted with a significantly higher accuracy (p = 0.009) using MIR spectra of evening milk samples compared to morning samples, with RMSEP values of respectively 0.182 and 0.197 mmol/L and R2 values of 0.613 and 0.502. These results suggest a time delay between variations in blood plasma NEFA and related milk biomarkers. Based on the MIR spectra of evening milk samples, cows at risk for a negative energy status, indicated with detrimental morning blood plasma NEFA levels (> 0.6 mmol/L), could be identified with a sensitivity and specificity of respectively 0.831 and 0.800. As this model can be applied to millions of historical and future milk MIR spectra, it opens opportunities for regular metabolic screening and improved resilience phenotyping.

Effect of milking behavior on circulatory hormones and milk production in lactating Murrah buffaloes

The effect of milking temperament on plasma hormones, metabolites, milk yield and composition in lactating Murrah buffaloes was studied. Animals were selected from the institute herd and grouped as docile and nervous buffaloes, based on temperament score before and during milking. Blood sampling times were; before milking (-20 min.), after concentrate intake, after teat massage, during milking and 20 min. post- milking. Plasma prolactin (PRL), growth hormone (GH) and cortisol (CORT) concentrations were measured by enzyme-immunoassay procedures. Milk yields of individual buffaloes were recorded and milk composition (fat, protein, lactose, SNF, SCC) determined. Milk yield was significantly lower (P<0.05) in nervous buffaloes in comparison to docile buffaloes. Mean fat, protein, lactose and SNF varied non-significantly between the groups. Milk SCC and plasma NEFA concentration was more (P<0.05) in nervous buffaloes than in docile buffaloes. Milking temperament significantly influenced plasma PRL (P<0.01) and CORT release (P<0.05) but GH was unaffected. Concentrate feeding prior to milking induced release of plasma PRL and CORT without affecting GH and oxytocin levels. Teat stimulus further enhanced release of PRL, oxytocin and CORT hormone in both the groups. Plasma PRL, cortisol, oxytocin and GH varied significantly (P<0.01) before, during and after milking (P<0.01). Basal PRL, GH and CORT were attained 20 minutes after the completion of milking in both the groups. The results show that the behavior of buffaloes at milking influenced release of galactopoietic hormones (PRL, CORT, GH and oxytocin), milk yield and SCC, while milk fat, protein, lactose and SNF remain unaffected.

Risk Assessment and Consequences of Retained Placenta for Uterine Health, Reproduction and Milk Yield in Dairy Cows

The objective of the study was to determine the value of metabolic indicators characterising the energy and acid-base metabolism of dairy cows for predicting the risk of retained placenta (RP). The connection between RP and different factors analysed, and the effect of RP on the development of puerperal metritis (PM) as well as on reproduction and milk production was studied. A total of 105 Holstein-Friesian cows were included and sampled between days -14–0 prepartum and then on days 4, 10–14, 28–35, 56–63 and 84–91 postpartum, for metabolic tests. From day 4, at times coinciding with the days of metabolic sampling, uterine involution and metritis were monitored by clinical examination, and from days 28–35 ovarian activity was monitored by ultrasonography. On days -14–0, the plasma non-esterified fatty acids (NEFA) concentration showed a positive Odds Ratio (OR) 102.1, P < 0.05; while urinary net acid-base excretion (NABE) exhibited a negative correlation (OR 0.99; P < 0.05) with the odds of RP. NEFA and NABE were negatively correlated (Pearson’s coefficient: -0.24; P < 0.05). Ketonuria of grade ≥ 2+ increased the probability of RP (OR: Infinite; P < 0.05). On day -14–0 prepartum, elevated plasma NEFA concentration, decreasing urinary NABE and grade ≥ 2+ ketonuria indicates a higher risk of RP. The odds of RP were not influenced by parity, sex and viability of the calf, and the calving assistance. RP increased the risk of PM (OR: 27.3; P < 0.0001). The RP alone did not exert an influence on the metabolic status, reproductive performance or milk production of cows.

Seasonal Variation in Plasma Nonesterified Fatty Acids of Lake Sturgeon (Acipenser fulvescens) in the Vicinity of Hydroelectric Facilities

To establish the effects of hydroelectric generation on the health of lake sturgeon (Acipenser fulvescens), seasonal variations in plasma nonesterified fatty acids (NEFAs) upstream and downstream from hydroelectric stations were measured over a 2-yr period. Plasma NEFA profiles were also compared up- and downstream of the stations for differences in utilization of individual NEFA species as substrates for lipid oxidation. Significantly higher levels of total plasma NEFA were found in lake sturgeon upstream (2355 ± 395.9 nmol/mL) compared with those downstream (798 ± 133.5 nmol/mL) of the generating stations during the spring. The NEFA profiles for several key fatty acid species differed significantly among seasons up- and downstream of the facilities. In particular, during spring and summer, the levels of oleic acid (18:1n9) were highest upstream of the stations and levels of a polyunsaturated fatty acid, docosahexaenoic acid (22:6n3), were higher below rather than above the stations. The differences in plasma NEFA concentration may be attributed to altered nutritional status due to the varying flow regime located downstream of the hydroelectric stations.

EFFECTS OF FEEDING CANOLA-MEAL-PROTECTED-TALLOW OR SOYBEAN-MEAL-PROTECTED-TALLOW IN THE LOW-ROUGHAGE DIET OF DAIRY COWS IN EARLY LACTATION

Fifteen Holsteins and 12 Ayrshires were randomly assigned within breed and lactation category to one of three isonitrogenous concentrates containing 0% protected tallow (C), 8% soybean-meal-protected-tallow (SPT), or 8% canola-meal-protected-tallow (CPT) which they received during the first 15 wk of lactation. Concentrates and alfalfa hay cubes were offered ad libitum in the ratio 70:30. Statistical analyses compared the effects of diets containing protected tallow (PT) versus the control and secondly the effects of the SPT diet versus the CPT diet. When compared to the control, protected tallow diets significantly increased (P < 0.05) the yields of milk and milk fat and the gross efficiencies of conversion of energy and protein. Plasma NEFA concentration also was significantly higher with PT diets (P < 0.05) than in the control. PT diets significantly reduced milk protein percentage (P < 0.05). There were no significant differences between the SPT and CPT diets for any parameters measured except apparent digestibility of ether extract which was significantly higher for the canola-meal-protected-tallow diet (P < 0.01). Key words: Dairy, cow, milk, composition, protected, lipid, canola

URINARY CATECHOLAMINE EXCRETION AND PLASMA NEFA CONCENTRATION IN SMALL-FOR-DATE INFANTS

Urinary catecholamine excretion, blood glucose, and plasma nonesterified fatty acids (NEFA) concentration were studied in five full-term, seven premature, and 22 small-for-date (SFD) babies (16 at term and six prematurely born) during the first 8 to 10 days of life. Episodes of hypoglycemia (arbitrarily designed as &lt; 40 mg/100 ml for full term and &lt; 30 mg/100 ml for premature infants) were observed between the second and fifth day of age in 12 SFD babies. During their low blood sugar period, these infants exhibited a significantly higher catecholamine excretion (three- to fourfold for norepinephrine and five- and sixfold for epinephrine) when compared to full term, premature, and "nonhypoglycemic" SFD babies. All SFD babies during the first 2 days of life showed a significantly higher plasma NEFA concentration than the other groups of neonates; among the former, the hypoglycemic ones had a tendency to maintain for a longer period a higher NEFA concentration than the nonhypoglycemic ones. These findings show that SFD babies are capable of reacting to an hypoglycemic stress by mobilizing their fat stores and by releasing catecholamine; therefore, adrenal medullary unresponsiveness cannot be considered as a cause of their transient neonatal hypoglycemia.