Heat stress negatively impacts on a variety of animal production parameters. Advances in management strategies have alleviated some of the negative impacts of thermal stress on farm animals, but production continues to markedly decrease during heat events in summer, particularly in dairy cattle. In this paper we introduce a Dairy Risk Assessment Program (DRAP). The DRAP is a user-friendly software package designed to assist users in predicting heat loads in dairy cow herds. DRAP was developed over three Australian summers using climatic data (temperature, humidity, solar radiation and wind speed), cow production data (milk yield and milk quality), and physiological data (respiration rate and body temperature). The data were used to develop mathematical algorithms which can predict animal response to climatic variables. This software package is designed to be used by the dairy industry to better manage cows during times of elevated environmental temperatures by equipping producers, managers, and dairy industry personnel with Dairy Heat Load Index (DHLI) values which were calculated based upon site information, stock characteristics, management practices, and mitigation variables specific to their dairy production unit. When a heat event is imminent producers can then introduce management strategies such as providing shade or additional water troughs or implementation of nutritional strategies. Some of these nutritional strategies include dietary chromium picolinate, betaine and antioxidant supplementation or altering the rate of starch fermentation. These nutritional strategies are discussed at some length in this paper.

An experiment was conducted to evaluate the effects of Bacillus coagulans ATCC 7050 (B. coagulans) on the performance, intestinal morphology and microflora of broiler chickens. Six-hundred 1-day-old broilers were randomly assigned into five treatment groups with four replicates for 42 days. There were five dietary treatments: negative control, positive control (antibiotics, 200 mg/kg zinc–bacitracin), 0.10, 0.20 and 0.25 g/kg B. coagulans. Dietary B. coagulans improved feed conversion ratio throughout the entire experimental period compared with the negative control (P = 0.02). Dietary B. coagulans significantly increased the number of lactobacilli (P = 0.01) and tended to decrease coliform bacteria (P = 0.06) in the duodenum. Dietary B. coagulans tended to increase villous height (P = 0.08) but had no effect on crypt depth in the jejunum. There were no significant differences (P > 0.05) in serum cholesterol, triglyceride, high density lipoprotein cholesterol and low density lipoprotein cholesterol between groups. In conclusion, the present data indicate that administration of B. coagulans ATCC 7050 improved feed conversion ratio in broiler chickens, possibly via improving the balance of intestinal microflora.

Pigs are comparatively less heat tolerant than other species of production animals, which poses challenges for stock productivity and management during seasonal heat waves that occur in summer. The issues surrounding heat and pig production are predicted to increase, based on the actions of climate change increasing the intensity, frequency and duration of heat waves. Furthermore, future growth areas of pig production are going to be in tropical regions such as South-east Asia and Latin America. Efforts by the pig to dissipate excess body heat come at a cost to health and divert energy away from growth, compromising efficient pig production. Management of heat stress requires multiple strategies, and recent research is improving the understanding of the application of nutritional strategies to ameliorate the effects of heat stress. In particular the use of feed additives is an important, flexible and economical method to alleviate heat stress and the intensive nature of pig production lends itself to the use of additives. Some specific examples include antioxidants, betaine and chromium, which have been proved effective or being tested in mitigating some certain impacts of heat stress in pigs. The aim of this review is to summarise recent advances in the nutritional management of heat stress in pigs.

This study was conducted to investigate the effects of different levels nanoparticles of chromium picolinate (NanoCrPic) on the performance, immune responses, mineral retention, and tissues accumulation of chickens. A total of 180 broilers were randomly allocated into 0 (control), 500 ppb (µg kg -1 ) Cr and 3000 ppb Cr groups with 6 replicates (10 birds/pen) for a 35-day experiment, the Cr is nanoparticles of chromium picolinate (NanoCrPic). In addition, 36 birds were used for metabolic experimental investigation. The results of the experimentation indicated that there were no significant differences in average body weight gain between groups, but feed conversion ratio (FCR) in 3000 ppb group was better than control group during 1-21 days. The carcass yields slightly lower in 3000 ppb group than control (p<0.1). Retention ratio of Zn, Fe, Mn, Ca, and P were significantly (p<0.05) increased in the 500 ppb Cr group. The addition of NanoCrPic caused increased mineral concentrations, such as Cr, Ca and P in the subjects' livers. Furthermore, the addition of NanoCrPic significantly increased lymphocytes and decreased both heterophils and H/L ratio (p<0.05). The ND (Newcastle disease) antibody titer was not affected in the broilers. In conclusion, supplemental NanoCrPic improved the retention of Zn, Fe Ca, notably it increased the concentration of Cr and Ca in the liver, and also increased the number of lymphocytes in broiler chickens.

Chromium (Cr) is an essential mineral element and has been used in pig diets to improve growth performance, insulin sensitivity, immune response and carcase traits and to reduce heat or other stress responses. The aims of thiss study were to determine the impact of nano-sized chromium tripicolinate (nCrPic) on growth performance, feed efficiency and carcase characteristics of finisher gilts during the summer period. A total of 60 finisher Large White x Landrace gilts were stratified on initial weight and then within strata randomly allocated into two treatment groups in three replicates during mid-summer for 28 days. All pigs were housed in individual pens and had ad libitum access to feed and water. Pigs were fed either a control finisher diet (wheat-based diet containing 13.8 MJ digestible energy (DE) per kilogram and 0.56 g available lysine/MJ DE) or a control diet containing 400 ppb Cr as nCrPic. Dietary nCrPic supplementation increased feed intake by 6 % over the entire study (P = 0.05). In particular, dietary nCrPic increased average daily feed intake (ADFI) by 8 % (P = 0.02) during the final 2 weeks of the study. Moreover, dietary nCrPic tended to improve average daily feed (ADFI) over the entire study (P = 0.09). However, there were no significant effects of nCrPic on feed conversion ratio (FCR), final weight, hot standard carcase weight (HCWT), P2 depth or dressing percentage. Plasma cortisol was decreased by 25 % (P = 0.06) by dietary nCrPic supplementation. However, there were no effects of nCrPic on plasma glucose, insulin and nonesterified fatty acids (NEFA), might because of the higher feed intake. In conclusion, this study demonstrates that dietary nCrPic supplementation at 400 ppb can increase feed intake in finisher gilts during mid-summer, suggesting that nCrPic can ameliorate some of the negative effects of heat stress in pigs, possibly via decreased of circulating cortisol.

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The aim of the present study was to evaluate the effect of the different-sized particles of chromium (Cr) picolinate (CrPic) and dietary fat on growth performance, carcass traits and insulin sensitivity of finishing pigs. Ninety-six Large White × Landrace gilts were stratified on bodyweight, housed in pens of three pigs and then, on a pen basis, randomly allocated to eight treatment groups in a 2 × 4 factorial design for 6 weeks. The respective factors were dietary fat (2.2% or 5.7%) and dietary CrPic (0 mg/kg, 400 mg/kgnormal-size CrPic, 400 mg/kg 1-μm CrPic (μCrPic), or 400 mg/kg 100-nm CrPic (nCrPic)). Over the first 21 days, average daily gain (ADG) was increased by dietary CrPic (0.94 vs 1.01 kg/day, P = 0.021), although there was no difference (P = 0.17) between the CrPic particle sizes. High dietary fat also increased ADG over this period (0.96 vs 1.03 kg/day, P = 0.013). However, the responses to both dietary CrPic and fat diminished over time and so there was no effect of CrPic (P = 0.35) or fat (P = 0.93) on ADG over the full 42 days. Dietary CrPic increased carcass weight and muscle depth and decreased P2 backfat. Furthermore, dietary Cr decreased plasma insulin (7.66 vs 5.09 mU/L, P = 0.018) and the homeostatic model assessment (1.25 vs 0.82, P = 0.009), indicating an improvement in insulin sensitivity. In conclusion, dietary Cr can increase ADG and improve carcass traits and insulin sensitivity in lean pigs. There were few differences among particle sizes, possibly because the response to dietary CrPic may already be maximised at 400 mg/kg.

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