Impacts of organic manganese supplementation on blood mineral, biochemical, and hematology in Afshari Ewes and their newborn lambs in the transition period.

OBJECTIVE: Maternal mineral status, including manganese (Mn), is critical for fetal growth as well as the health of the newborn lamb. Consequently, it is essential to supply minerals at sufficient levels for the pregnant animal to achieve the development of the embryo and fetus during gestation. METHODS: The current research was conducted to investigate the impact of organic Mn supplementation on blood biochemical, other mineral and, hematology in Afshari ewes and their newborn lambs in the transition period. Twenty-four ewes were randomly divided into three groups with eight replications. The control group was fed with a diet without organic Mn. The other groups were fed a diet supplemented with 40 (recommended by the NRC) and 80 (twice-recommended by the NRC) mg/kg of DM organic Mn. RESULTS: In this study, the consumption of organic Mn caused a significant increase in ewes and lambs plasma Mn concentration. Moreover, in the groups mentioned, levels of glucose, insulin, and superoxide dismutase were significantly increased in both ewes and lambs. Concentrations of total protein and albumin were higher in ewes fed whit organic Mn. In both ewes and newborn lambs, the levels of red blood cells, hemoglobin, hematocrit, mean corpuscular hemoglobin, and mean corpuscular concentration in groups fed with organic Mn raised. CONCLUSION: In general, the nutrition of organic Mn, improved factors of blood biochemical and hematology in ewes and their newborn lambs, and since the twice-recommended NRC level did not cause poisoning, it was recommended to supplement the diet with 80 mg of organic Mn per kg of DM.

Effects of late-gestation heat stress independent of reduced feed intake on colostrum, metabolism at calving, and milk yield in early lactation of dairy cows.

The objective of this study was to differentiate the effects of acute heat stress (HS) from those of decreased dry matter intake (DMI) during the prepartum period on metabolism, colostrum, and subsequent production of dairy cows. Holstein dairy cows (n = 30) with similar parity and body weight were randomly assigned to 1 of 3 treatments on 45 d before calving: (1) cooled (CL, n = 10) conditions with ad libitum feed intake, (2) HS conditions with ad libitum feed intake (n = 10), and (3) pair-fed cooled (CLPF, n = 10) with reduced DMI similar to the HS group while housed under cooled conditions. The reduction in the amount of feed offered to the CLPF cows was calculated daily as the percentage decrease from the average DMI of HS cows relative to the CL cows. For CLPF and CL cows, barns provided shade, sprinklers, and fans, whereas the HS cows were provided only with shade. Cows in all groups received individually the same total mixed ration. Cows were dried off 60 d before the expected calving. Cows in the HS group and, by design, the CLPF cows had reduced DMI (~20%) during the experiment. Heat stress decreased gestation length, first colostrum yield, and calf birth weight compared with CL and CLPF cows. Milk yield decreased 21% (5 kg) in the HS and 8% (2 kg) in CLPF cows, indicating that reduced feed intake during late gestation accounted for 60% of the total reduced milk yield. The CLPF cows exhibited an elevated NEFA concentration compared with the CL and HS cows. The HS cows had a greater mRNA abundance of HSP70 in the peripheral blood leukocytes at 21 d prepartum compared with the other groups. At calving, the mRNA abundance of HSP70 was greater in HS cows, followed by CLPF, compared with the CL cows. In conclusion, HS during the late gestation period caused metabolism and production differences, which were only partially attributed to reduced feed intake in dairy cows.

Long-term impacts of late-gestation maternal heat stress on growth performance, blood hormones and metabolites of newborn calves independent of maternal reduced feed intake.

The objective of this study was to evaluate the effects of heat stress in late gestation independent of maternal reduced feed intake on performance, blood hormones and metabolites, and immune responses of dairy calves from birth through weaning. A total of 30 multiparous Holstein cows at 45 d before expected calving were randomly assigned to one of 3 groups: (1) thermal neutral (CL, n = 10) conditions with ad libitum feed intake (10% of refusals on an as-fed basis); (2) pair-fed thermal neutral (CLPF, n = 10) conditions to reduce feed intake to levels similar to the heat stress (HS) group while reared under thermoneutral conditions (80% of the CL group); or (3) heat stress (HS, n = 10) conditions with ad libitum feed intake. Pair-feeding was conducted to quantify the confounding effects of dissimilar feed intake. Calves (10/group) born to cows that were exposed to cooling (IU-CL), pair-feeding (IU-CLPF), or heat stress (IU-HS) were used from birth through weaning. After birth, all the calves were managed under identical conditions. IU-HS calves had lower birth weight, and hip height at birth and 14 d of age. Compared with IU-CL and IU-CLPF calves, IU-HS calves had lower serum concentration of IgG and apparent efficiency of IgG absorption but higher serum insulin concentrations. Cortisol concentration in serum was higher in IU-HS and IU-CLPF calves compared to IU-CL calves. The neutrophil percentage was lower in IU-CL calves than in IU-HS and IU-CLPF calves. Neutrophil-lymphocyte ratio was higher in IU-HS calves compared to IU-CLPF and IU-CL calves. The mRNA expression of TNFα of IU-HS calves was downregulated compared with IU-CL and IU-CLPF calves. In summary, maternal HS during late gestation reduces calf birth weight and dramatically alters blood hormones and metabolites, but its effect on immune system function was not independent of maternal reduced feed intake.

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ.

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro-organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.

Effect of calcium with and without probiotic, lactose, or both on organ and body weights, immune response and caecal microbiota in moulted laying hens.

A total of 72 laying hens were used to investigate the effect of probiotic and lactose on body weight loss, tibia ash, antibody production against sheep red blood cell (SRBC), heterophile-to-lymphocyte (H/L) ratio and gut microbiota in a common moulting method for 14 d. Hens were randomly allocated to 6 experimental groups consisting of (i) full feed (FF), (ii) feed withdrawal (FW), (iii) FW with calcium (Ca), (iv) FW with Ca and offering 7 g/lit lactose in drinking water (CaL), (v) FW with Ca and offering 1 g/lit probiotic in drinking water (CaP), and (vi) FW with Ca and offering a mixture of lactose and probiotic in drinking water (CaLP). The results showed body weight loss in all FW groups were more than 25% that was significantly higher than FF group (p < 0.05). The relative organ weights of hens in FW groups were lower than FF group; especially, it was significant for liver and ovary (p < 0.05). No significant difference was observed between all groups for tibia ash. The highest H/L ratio was related to FW group and offering Ca and lactose numerically and probiotic alone significantly resulted in decrease of this ratio (p < 0.05). The results also showed no significant difference for antibody production against SRBC among experimental groups. The highest coliform bacteria numeration observed in FW group and lactose could significantly reduce this population (p < 0.05). Lactic acid bacteria (LAB) numeration demonstrated a significant difference among treatments, so that FF hens had higher LAB than others (p < 0.05). In addition, FW moulted hens had significantly lower LAB compared to other moulted hens (p < 0.05), except for Ca group. In conclusion, probiotic and lactose was effective in maintaining caecal microbiota balance and improving immunity in hens exposed to moulting.

Assessment of the mobile bag method for estimation of in vivo starch digestibility.

The objective was to assess the ability of the in situ mobile nylon bag method for predicting small intestinal and total tract starch digestibility. Starch disappearance was measured for 18 samples of different cereals and legumes subjected to different physical and chemical processing methods and compared with coherent in vivo digestibility. Starch disappearance was measured both with and without initial ruminal pre-incubation during 4 h. Bags were retrieved from either the ileal cannula or faeces. Two dry Danish Holstein cows fitted with rumen cannulas were used for rumen pre-incubations and two lactating Danish Holstein cows fitted with duodenal and ileal cannulas were used for intestinal incubations. Rumen pre-incubation had no significant effect on disappearance from bags recovered in faeces. The disappearance of legume starch was lower, both in the rumen and small intestine, compared with starch from barley, wheat, oats, ear maize and maize. Transit times of the mobile bags from duodenum to ileum were not significantly different between feeds. A weak positive correlation was found between in vivo small intestinal and total tract digestibility of starch and disappearance obtained using the mobile bag technique across a broad range of starch sources. Omitting two less conventional starch sources (NaOH wheat and xylose-treated barley) resulted in a high (0.87) correlation between total tract in vivo digestibility and mobile bag disappearance. The use of the mobile bag method for estimation of in vivo starch digestibility will therefore depend on the starch type.