Altitude effects on technology and productivity of small bovine farms (milk meat) in Veracruz (Gulf of Mexico)

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15–22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.     

Herbage intake of dairy cows in mixed sequential grazing with breeding ewes as followers

This study aimed to evaluate the hypothesis that mixed sequential grazing of dairy cows and breeding ewes is beneficial. During the seasons of spring–summer 2013 and autumn–winter 2013–2014, 12 (spring–summer) and 16 (autumn–winter) Holstein Friesian cows and 24 gestating (spring–summer) and lactating (autumn–winter) Pelibuey ewes grazed on six (spring–summer) and nine (autumn–winter) paddocks of alfalfa and orchard grass mixed pastures. The treatments “single species cow grazing” (CowG) and “mixed sequential grazing with ewes as followers of cows” (MixG) were evaluated, under a completely randomized design with two replicates per paddock. Herbage mass on offer (HO) and residual herbage mass (RH) were estimated by cutting samples. The estimate of herbage intake (HI) of cows was based on the use of internal and external markers; the apparent HI of ewes was calculated as the difference between HO (RH of cows) and RH. Even though HO was higher in CowG, the HI of cows was higher in MixG during spring–summer and similar in both treatments during autumn–winter, implying that in MixG the effects on the cows HI of higher alfalfa proportion and herbage accumulation rate evolving from lower residual herbage mass in the previous cycle counteracted that of a higher HO in CowG. The HI of ewes was sufficient to enable satisfactory performance as breeding ewes. Thus, the benefits of mixed sequential grazing arose from higher herbage accumulation, positive changes in botanical composition, and the achievement of sheep production without negative effects on the herbage intake of cows.     

Pharmacokinetics and effects of alfaxalone after intravenous and intramuscular administration to cats

AIMS: To determine the pharmacokinetics, and anaesthetic and sedative effects of alfaxalone after I/V and I/M administration to cats.

METHODS: Six European shorthair cats, three males and three females, with a mean weight of 4.21 (SD 0.53) kg and aged 3.8 (SD 0.9) years were enrolled in this crossover, two–treatment, two-period study. Alfaxalone at a dose of 5?mg/kg was administered either I/V or I/M. Blood samples were collected between 2–480 minutes after drug administration and analysed for concentrations of alfaxalone by HPLC. The plasma concentration-time curves were analysed by non-compartmental analysis. Sedation scores were evaluated between 5–120 minutes after drug administration using a numerical rating scale (from 0–18). Intervals from drug administration to sit, sternal and lateral recumbency during the induction phase, and to head-lift, sternal recumbency and standing position during recovery were recorded.

RESULTS: The mean half-life and mean residence time of alfaxalone were longer after I/M (1.28 (SD 0.21) and 2.09 (SD 0.36) hours, respectively) than after I/V (0.49 (SD 0.07) and 0.66 (SD 0.16) hours, respectively) administration (p<0.05). Bioavailability after I/M injection of alfaxalone was 94.7 (SD 19.8)%. The mean intervals to sternal and lateral recumbency were longer in the I/M (3.73 (SD 1.99) and 6.12 (SD 0.90) minutes, respectively) compared to I/V (0 minutes for all animals) treated cats (p<0.01). Sedation scores indicative of general anaesthesia (scores >15) were recorded from 5–15 minutes after I/V administration and deep sedation (scores 11–15) at 20 and 30 minutes. Deep sedation was observed from 10–45 minutes after I/M administration. One cat from each group showed hyperkinesia during recovery, and the remainder had an uneventful recovery.

CONCLUSIONS AND CLINICAL RELEVANCE: Alfaxalone administered I/V in cats provides rapid and smooth induction of anaesthesia. After I/M administration, a longer exposure to the drug and an extended half life were obtained compared to I/V administration. Therefore I/M administration of alfaxalone could be a reliable, suitable and easy route in cats, taking into account that alfaxalone has a slower onset of sedation than when given I/V and achieves deep sedation rather than general anaesthesia.     

Effects of p.o. administered xylitol in cats

Xylitol is commonly used as sugar substitute in households. While it has numerous beneficial effects on human health, it is highly toxic to dogs. The goal of this study was to examine whether xylitol has similar deleterious effects, such as hypoglycaemia and acute hepatic failure, on cats. Our research included six healthy middle‐aged cats. Xylitol was dissolved in deionized water and administered p.o. at three doses (100, 500 and 1,000 mg/kg body weight). These dosages have been considered toxic and can cause liver failure or even death in dogs. After every xylitol administration, the basic health status and the blood glucose of cats were observed regularly. Additionally, prior to and 6, 24 and 72 hr after xylitol administration, blood samples were taken to check complete blood count, clinical biochemical parameters and enzymes such as ALT, ALKP, GGT, GLDH, bile acids, BUN, creatinine, phosphate, total protein, albumin, sodium and potassium. There were no significant changes (p > .05) in any of the haematological or biochemical parameters. Blood glucose concentrations did not show any significant alterations, except at 1,000 mg/kg dose, where a mild but significant increase was observed, but it was in physiological range. Based on our results, xylitol did not induce toxic effects on cats.     

Effect of resistant starch on the intestinal health of old dogs: fermentation products and histological features of the intestinal mucosa

The effects of resistant starch (RS) intake on nutrient digestibility, microbial fermentation products, faecal IgA, faecal pH, and histological features of the intestinal mucosa of old dogs were evaluated. The same formulation was extruded in two different conditions: one to obtain elevated starch cooking degree with low RS content (0.21%) and the other lower starch cooking with high RS content (1.46%). Eight geriatric Beagles (11.5 ± 0.38 years old) were fed each diet for 61 days in a crossover design. Food intake, nutrient digestibility, fermentation products, faecal pH, and faecal IgA were examined via variance analysis. Histological results of intestinal biopsies were assessed via Wilcoxon test for paired data. The morphometric characteristics of large intestine crypts were evaluated via paired t tests (p < .05). Protein, fat, and energy digestibilities were higher for the low‐RS diet (p < .05). Dogs receiving the high‐RS diet had lower faecal pH and higher values for propionate, butyrate, total volatile fatty acids, and lactate (p < .05). No differences between diets were found in the histological parameters of the gut mucosa, and only a tendency for deeper crypts in the descending colon was observed for dogs fed the high‐RS diet (p = .083). The intake of a corn‐based kibble diet manufactured with coarse ground raw material and low starch gelatinization to obtain 1.4% of RS affected microbial fermentation products and faecal pH and tended to increase crypt depth in the descending colon of old dogs.     

Effect of feed intake level and dietary protein content on the body temperature of pigs housed under thermo neutral conditions

Feed intake and diet composition appear to affect the body temperature of pigs. Two trials were conducted to analyse the effect of feed intake level and dietary protein content on the intestinal temperature (IT) of pigs housed under thermo neutral conditions. Ten pigs (64.1 ± 1.3 kg initial body weight) fitted with an ileal cannula were used. A thermometer set to register the IT at 5‐min intervals was implanted into the ileum through the cannula. In both trials, the ambient temperature ranged from 19.1 to 21.6°C and the pigs were fed at 07:00 and 19:00 hr (same amount each time). In trial 1, the pigs were fed daily 1.2 or 1.8 kg of a wheat–soybean meal diet. The IT followed a similar pattern along a 24‐hr period regardless the feed intake level. The IT rapidly increased up to 0.61 and 0.74°C after the morning meal and up to 0.53 and 0.47°C after the evening meal in pigs fed 1.2 and 1.8 kg/d respectively. The postprandial IT was higher in pigs fed 1.8 kg after each meal (p < .05). In trial 2, pigs were fed daily 1.8 kg of a low (11%) or a high (22%) crude protein diet. The IT followed a similar pattern along the 24‐hr period regardless the dietary protein level. The postprandial IT did not differ between pigs fed the low protein or the high protein (p > .10). The IT rapidly increased up to 0.66 and 0.62°C after the morning meal in pigs fed the high‐ and low‐protein diet (p < .05), but there was no change after the evening meal (p > .10). In conclusion, the feed intake level affected the IT of pigs housed under TN conditions, but the dietary protein content had no effect.     

Sex‐dependent responses of perch to changes in water clarity and temperature

Rising temperatures and decreasing water transparency of lakes have strong wide ranging effects on fish. Fish responses to various changes in the environment are usually species‐dependent, but responses may also vary within species. In general, large individuals are considered to be more sensitive to environmental variation due to higher energy demand, than smaller individuals. Similarly, large individuals require more food to maintain bodily functions and are thus more sensitive to resource and food scarcity. These size‐specific responses to environmental gradients are also sex‐dependent in species that exhibit sexual size dimorphism (SSD). We studied in enclosures with short‐term experiments how rising temperatures and decreasing water transparency regulate the feeding rates of female and male European perch (Perca fluviatilis L.). To explore experimental results, we calculated perch SSD in nine lakes with varying environmental conditions using previously collected field data. The results of the experiments revealed that the combined effect of water transparency and temperature on the feeding rate of fish is gender‐dependent: feeding rate of females decreased more than that of males. The experimental results were also supported by field data that revealed a negative relation between water transparency and the magnitude of SSD in perch. Our results suggest that rising temperatures and decreasing water transparency may potentially decrease fish size in a sex‐dependent manner. As female size is one of the main demographic traits determining the reproductive success of a fish population, changing environments may have unexpected and far‐reaching consequences on fish population dynamics.     

Abscisic Acid May Alter the Salicylic Acid‐Related Abiotic Stress Response in Maize

The effect of 0, 0.05 or 0.1 mm abscisic acid treatment on chilling tolerance and salicylic acid‐related responses was investigated in young maize seedlings (Zea mays L., hybrid Norma). Although the pre‐treatment of maize seedlings with abscisic acid slightly decreased the chlorophyll content, it also reduced the level of chilling injury caused by 6 days of cold treatment at 5 °C. Under normal growth conditions, increased levels of bound salicylic acid and of bound ortho‐hydroxycinnamic acid were observed in the leaves during abscisic acid treatment. In the roots, abscisic acid did not affect the free and bound salicylic acid levels, but increased the amount of free and bound ortho‐hydroxycinnamic acid. The activity of glutathione‐S‐transferase increased on the 3rd day of abscisic acid treatment, whereas it did not change when followed by cold stress, compared with the control leaves. In the roots, the activities of glutathione reductase, glutathione‐S‐transferase and ascorbate peroxidase increased during the abscisic acid treatment, and those of glutathione‐S‐transferase and ascorbate peroxidase were also stimulated when abscisic acid pre‐treatment was followed by cold stress, compared with the control roots. Our results suggest that an overlap may exist between the abscisic acid‐induced cold acclimation and the salicylic acid‐related stress response.