Understanding the efficacy of organic trace minerals has been increasingly important over the past few years as a result of increased customer awareness of their benefits and the increase in the number of commercial products available to the customer. Organically bound trace minerals of interest in animal nutrition specifically include iron, zinc, manganese, copper, cobalt, and selenium. These elements have been shown to improve reproductive efficiency as measured by conception rate, alleviated calving, and reduced placenta expulsion rate. Additional benefits include improved growth performance of calves. The field trials in the period of 2005 – 2007 with Charolais breed beef cattle cows and calves verified efficacy of the premix PROTRACE G containing Fe, Zn, Cu, Mn, and Co chelates, Se-amino acid (selenomethionine), potassium iodide, and vitamins A, D3 and E. Average calving rate of experimental group cows fed diet with added premix was 20 – 30 min, placenta expulsion time - 28 – 31 min, but in control group fed only basal diet - 2 h 21 min and 1 h 30 min – 2 h 09 min (p is less than 0.05) respectively. Live weight gain of calves and heifers of the experimental group was on 35 – 39% higher (p is less than 0.05) than that in the control group.

The changes in the serum immunoglobulins concentration were investigated in newborn heifers from birth to 7 days of age. The mothers of calves were determined serum and colostrum immunoglobulins (Ig) concentration. The research was carried out at the Latvia University of Agriculture (LLU), in dairy farm ''Ligotnes'' of the Research and Study Farm ''Vecauce'', in a loose housing system with 530 cows, of which 430 were milking cows. The cows during the dry period were kept tethered in the farm. Eighteen heifers and their dams (Latvian Brown and Holstein breeds) which calved from 30 November 2010 to 23 January 2011 were used in this study. The calves' serum total immunoglobulin concentration at birth was 9.0 ±1.31 mg dLE-1 (or 0.09 mg mLE-1), and after 24 hours (h) it increased significantly to 4.3 mg dLE-1 (or 0.043 mg mLE-1), p is less than 0.05. The immunoglobulin G (IgG) concentration in calf serum after birth was 6.8 ±1.50 mg dLE-1 (or 0.068 mg mLE-1), and after 1 day and after 7 days it did not change significantly. The average Ig serum concentration in cows was 12.6 ± 1.36 mg dLE-1(or 0.126 mg mLE-1), and Ig concentration in colostrum was 18.5 ± 1.68 mg mLE-1. On average, close correlation (r=0.56) was found between cow blood serum IgM and colostrum IgM. Correlation between cow and calf IgG serum concentration proved to be weak (r=0.49).

Studies have been conducted to find out the effect of the feeding of calves (Bos Taurus) with Jerusalem artichoke (Helianthus tuberosus) concentrate produced in Latvia containing the prebiotic – inulin. The study was performed on two groups of animals - a control group of 8 animals and test (prebiotic) group of 8 animals in summer (from June to August, 2013), and winter (from December, 2013 to February, 2014) in one of cow farm of Latvia, in the municipality of Bauska. Both groups were fed the whole milk, but the test group received additionally 12 g of Jerusalem artichoke powder (an average of 500 g kgE-1 inulin) per day. The overall health status and physiological parameters (temperature, heartbeat and breathing frequency) of both animal groups before the study were of the normal range. After the experiment, we found out that the calves of the test group during both winter (one case) and summer seasons (seven cases), had fewer cases of diarrhea than the control (winter months four cases and summer months nine cases) group animals, the average daily weight gain (control group 0.53 g, prebiotic group 0.75 g) and the total weight gain (control group 29.42 kg, prebiotic group 42.13 kg) during 56 test days was significantly higher ( p is less than 0.05) than that for the control animals. We concluded that the use of Jerusalem artichoke flour concentrate when fed to the calves generally gives positive impact on the development and growth of the calves, improves the status of the gastrointestinal tract and the morphometric indicators.

Methane is considered to be the main greenhouse gas (GHG) emitted by livestock. One method for reducing methane emissions from ruminants is to improve production efficiency, which reduces methane emissions per unit of product (FAO, 2010; Gworgwor, Mbahi, and Yakubu, 2006). There are many researches about prebiotics which can reduce methane production in livestock, for example, galacto-oligosaccharides reduced methane emission up to 11% (litres/day) (Zhou et al., 2004). There is almost no information about prebiotic inulin, so the aim of this research was to determine the impact of different dosages of inulin concentrate (50%) on the increase of calves’ body weight and its impact on methane emission, as well as to find out how the results change if it is added to barley flour not to milk as in our previous research. Approximately fifty days old, clinically healthy, different Holstein Friesian crossbreed calves kept in groups of 8, in a partly closed space with natural ventilation through windows were included in this research. Eight calves were in the control group (CoG) and sixteen received inulin (Pre12 (n = 8), Pre24 (n = 8)). At the beginning of the experiment – the 28th and 56th day - we determined each calf’s weight and measured the methane level in the rumen by using the PICARROG-2508 gas analyser (Fleck, 2013). We concluded that inulin supplement significantly (p ≤ 0.05) increased the live weight gain comparing Pre24 and CoG. The highest methane production on 1 kg of body weight at the end of the research was detected in Pre24 – 1.24 mg mE-3 and the lowest in CoG – 0.99 mg mE-3.

Ruminants produce a large amount of methane (CH4 ) and carbon dioxide (CO2 ) in their foregut. These gases cause greenhouse effect. There are a lot of studies about different feed additives which can reduce the production of greenhouse gases in ruminants. Prebiotics can also change the amount of bacteria in animal gastrointestinal tract and reduce the occurrence of diarrhoea. The aim of this study was to test whether the prebiotic inulin affects the production of CH4 and CO2 in calves’ rumen and whether it affects the bacteria count in the rumen fluid and bacterial overgrowth in intestines. We used the flour of Jerusalem artichoke (Helianthus tuberosus L.) containing 50% of inulin. Approximately fifty days old, Holstein Friesian crossbreed calves were used in this study. Eight were in the control group, 8 received 12 g of flour and 8 received 24 g per day. On the 28th and 56th day of the research, we measured the amount of CH4 and CO2 in calves’ rumen took rumen fluid samples for bacterial analysis and urine to measure the level of phenol and indican. We concluded that adding the flour of Jerusalem artichoke at doses 12 g and 24 g did not significantly impact the production of CH4 and CO2 in calves’ rumen, the prebiotic inulin may suppress the growth of anaerobic microorganisms in the rumen at concentration 12 g of inulin reaching 56th day of experiment. The amount of phenol and indican in calves’ morning urine did not correlate with the faecal consistency of calves.

The article analyses the data obtained while evaluating red deer calves on the red deer breeding farm ‘Dumpji’ during the herd’s annual prophylactic check-up in December and April of the years 2013 and 2014. Farm is a private enterprise owned by a company located in Northern Latvia. The study comprises data for calves born in 2013 (n = 36) that were born from the same hinds, but from different stags in consecutive years. It was discovered that the calves’ liveweight gain in 24 hours significantly decreases during wintering period. After the wintering smaller body mass was observed in calves of both sexes born in 2014; however, the body mass of bull calves born in both years of reference considerably exceeded that of the hind calves. In the group of hind calves born in both years of the study period the liveweight loss was observed during the wintering. Nevertheless, at the age of 1.5 years the lowest liveweight among hind calves was 82.4 kg (year 2013), and the highest 129.6 kg (year 2014). In the group of spikers, during the winter period liveweight loss was not observed. Analysis of the results revealed a close positive correlation between the liveweight in December and the liveweight in the spring among spikers and heifers alike. The conducted analysis of influencing factors attests to the fact that the liveweight at the age of six months has material impact on the animals’ liveweight both in the spring and at the age of 1.5 years.

The present work aimed to evaluate the effect of sea buckthorn (Hippophae rhamnoides) extract on Cryptosporidium spp. invasion in calves. Sea buckthorn is a good source of vitamins, carotenoids, organic acids and tannins. It has been reported that it possesses anti-inflammatory effect, as well as anthelmintic and antibacterial activity. Research was conducted in a dairy cattle farm ‘Mežacīruļi’ during April and July 2015. Experimental (n = 10) and control (n = 10) groups of calves were used. The experimental group received a mix of aqueous alcohol sea buckthorn leaf and berry pomace extract, administered with milk, at dose of 5 – 8 mL twice a day for 20 days. The control group received only milk. Samples were analysed with the concentration McMaster technique. The results showed that there is no significant (p is greater than 0.05) difference in the number of oocysts per gram of faeces between the experimental and control groups. It was concluded that the administration of sea buckthorn leaf and berry pomace extract had no effect on Cryptosporidium spp. invasion in calves. Studies will be continued with a higher dose of extract.

The aim of this study was to determine the influence of Jerusalem artichoke flour feeding on the general health status of calves (Bos Taurus), the animal live weight gain and digestive canal morphological development in the first four months of life, as well as to find out the optimal of three inulin doses. Jerusalem artichoke (Helianthus tuberosus) concentrate produced in Latvia contains the prebiotic – inulin. The study was performed on four groups of animals - a control group of 10 animals and three prebiotic groups, 10 animals in each group. All groups were fed the whole milk, but the PreG6 group animals were fed daily with 6 grams of prebiotic, calves PreG12 group were fed with 12g of prebiotic, but each calf in PreG24 group – 24g of prebiotic per day. CoG control animals did not receive feed supplement. Faecal mass consistence of PreG6, PreG12 groups of animals was more stable within the whole research period than CoG. We found that the control group animal weight gain on the 56th research day is statistically significantly (p is less than 0.05) lower than of those calves that received inulin as a food supplement. The highest growth rates have shown PreG12 and PreG24 group of animals, significantly (p is less than 0.05) being ahead of PreG6 group of calves, the highest average daily live weight gain was observed in PreG24 group (0.95 ± 0.093 kg).

It is well known that secretion of gastric acid is regulated neurally by the stimulation of n.vagus and humorally by the activation of histamine H2 receptors in parietal cells. The purpose of the investigation was to clear up neural and humoral regulation mechanisms of gastric acid secretion in the postnatal ontogenesis of calves. Four calves from 5 to 14 weeks of age with chronical fistulae in abomasum have been investigated. Two electrode pH-probe has been used for measures. Atropine sulphate (0,06 mg kg*[-1) IV infusion) has been used to stop function of n.vagus, and cimetidine (0.16 mg kg*[-1) IV infusion) to block humoral regulation. The results clearly show that both, atropine sulphate and cimetidine, demonstrate some blocking influence on the HCL of abomasum in calves of different age.