Gastrointestinal functionality in animal nutrition and health: New opportunities for sustainable animal production

Effects of heat stress on animal physiology, metabolism, and meat quality: A review.

The digital transformation of agriculture has evolved various aspects of management into artificial intelligent systems for the sake of making value from the ever-increasing data originated from numerous sources. A subset of artificial intelligence, namely machine learning, has a considerable potential to handle numerous challenges in the establishment of knowledge-based farming systems. The present study aims at shedding light on machine learning in agriculture by thoroughly reviewing the recent scholarly literature based on keywords’ combinations of “machine learning” along with “crop management”, “water management”, “soil management”, and “livestock management”, and in accordance with PRISMA guidelines. Only journal papers were considered eligible that were published within 2018–2020. The results indicated that this topic pertains to different disciplines that favour convergence research at the international level. Furthermore, crop management was observed to be at the centre of attention. A plethora of machine learning algorithms were used, with those belonging to Artificial Neural Networks being more efficient. In addition, maize and wheat as well as cattle and sheep were the most investigated crops and animals, respectively. Finally, a variety of sensors, attached on satellites and unmanned ground and aerial vehicles, have been utilized as a means of getting reliable input data for the data analyses. It is anticipated that this study will constitute a beneficial guide to all stakeholders towards enhancing awareness of the potential advantages of using machine learning in agriculture and contributing to a more systematic research on this topic.

Machine Learning in Agriculture: A Comprehensive Updated Review.

Biomarkers of gastrointestinal functionality in animal nutrition and health

Impacts of climate change on the livestock food supply chain; a review of the evidence.

Heat stress is the most intriguing factor negatively influencing sheep production. Heat stress management in sheep requires multiple strategies. There are several recent research findings which help to understand the hidden intricacies of nutritional intervention ameliorating the effects of heat stress in sheep. Applications of feed additives in particular were found to be the most widely adapted methodology to alleviate heat stress in an economical way. The commonly attempted feed additives include antioxidants, betaine, chromium, insulin mimics, and manipulation of concentrates to slow fermentation. These applications were either proved to be effective, or are currently being evaluated for their potency in reversing some of the effects of heat stress in sheep. Therefore, this chapter is an attempt to review different viable nutritional strategies to ameliorate heat stress in sheep.

Nutritional strategies to alleviate heat stress in pigs

Feeding low-fiber and high-energy diets to dairy cows is one approach to ameliorate heat stress (HS) by reducing heat increment (HI) during digestion. However, rapidly and slowly fermentable cereal grains differ in their HI. The aim of this experiment was to quantify if feeding slowly fermentable grains ameliorated the physiological responses to HS and improved milk production (MP) in dairy cows. Holstein-Friesian lactating dairy cows were housed in shaded pens and were fed either a total mixed ration (TMR) plus wheat (TMRW), a TMR plus wheat treated with 2% of a commercial starch-binding agent (TMRB), or a TMR plus corn (TMRC) (n = 8 cows per diet) during summer in Queensland, Australia. Respiration rate (RR) and panting score (PS) were measured four times a day; rumen temperature (RuT) was recorded every 20 min, and rectal temperature (RT) and milk samples were obtained every 4 days. Cows fed slowly fermentable grains had higher milk production (MP) than cows fed TMRW, and cows fed TMRC had lower RT than those fed TMRW and TMRB (P < 0.001). Rumen temperature was positively correlated with temperature-humidity index and negatively correlated with MP (P < 0.05). In summary, feeding TMRC ameliorated HS as indicated by lower RT and improved MP in dairy cows. Milk production was improved with starch-binding agents; however, this was not associated with efficient thermoregulatory responses. Furthermore, determination of RuT enabled the prediction of changes in physiological variables and productive responses due to HS in lactating dairy cows.

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Effect of feeding slowly fermentable grains on productive variables and amelioration of heat stress in lactating dairy cows in a sub-tropical summer.

During heat stress (HS), livestock reduce metabolic heat production by lowering activity and feed intake. Because this has obvious consequences for productivity, the aim of these experiments was to investigate nutritional methods for reducing digestive metabolic heat production, thereby allowing livestock more opportunity to dissipate excess heat. In the first experiment, the fermentation rates of corn and wheat grains were compared in an in vitro gas production system containing buffered rumen fluid. This experiment showed that corn had a slower (-15%; < 0.001) rate of gas production than wheat and no differences in total amount of gas production after 24 h of incubation. In the second experiment, we hypothesized that the lower rate of fermentation of corn would reduce metabolic heat load in wethers and, in turn, improve tolerance to HS. Twenty-two Merino × Poll Dorset wethers were housed in 2 climate-controlled rooms and were fed either corn grain plus forage (CD; 39% starch) or wheat grain plus forage (WD; 37% starch) during 3 experimental periods: period 1 (P1), which consisted of 7 d of thermoneutral conditions (18 to 21°C and 40 to 50% relative humidity [RH]) and restricted feed intake (1.3 times maintenance); period 2 (P2), which consisted of 7 d of HS (28 to 38°C and 30 to 50% RH) and restricted feed intake; and period 3 (P3), which consisted of 7 d of HS as in P2 with unrestricted feed intake (1.5 times maintenance) in a randomized control experiment. Water was offered ad libitum. The level of HS was quantified by increases in rectal temperature (RT), respiration rate (RR), and left and right flank skin temperature (LFT and RFT, respectively) and blood acid-base balance. Rectal temperature, RR, LFT, and RFT were elevated ( < 0.001) during HS, especially when wethers had unrestricted feed intake (P3). Wethers fed CD had lower RR, RT, LFT, and RFT ( < 0.001) than wethers fed WD, and this benefit was greatest during HS (P2 and P3). The reduction in RR with CD resulted in less CO exhalation (greater partial pressure of CO2) and greater HCO3 ( < 0.05) than with WD, indicating reduced efforts to dissipate heat by evaporative heat loss via panting. The greatest heat from fermentation was apparent in WD wethers, which had elevated LFT compared with RFT ( < 0.001). Crucially, this large difference was not observed with the CD wethers, indicating that the slow rate of fermentation of CD was expressed as low heat released during feed fermentation in the rumen. These data demonstrated that feeding CD may be a useful management strategy to reduce the impact of high environmental heat loads in sheep.

Feeding slowly fermentable grains has the potential to ameliorate heat stress in grain-fed wethers

Selection for high productivity has resulted in ruminants adversely affected by heat stress (HS) due to their high metabolic rate and feed intake. One mechanism to ameliorate HS is to reduce the forage-to-concentrate ratio in the diet, although the inclusion of readily fermentable grains can reduce heat tolerance. The aim of these experiments was to investigate a chemical method for reducing the rate of fermentation of wheat and its effect on improving heat tolerance in sheep. In the first experiment, fermentation kinetics and buffered rumen fluid pH variation during in vitro incubation of corn, wheat, and 3% NaOH-treated wheat grains were compared. This experiment showed that corn and 3% NaOH-treated wheat had a slower (-23 and -22%, respectively; < 0.001) rate of gas production and elevated buffered rumen fluid pH ( < 0.001) compared with wheat. In the second experiment, 31 Merino × Poll Dorset wethers were housed in 2 climate-controlled rooms and were fed either corn grain plus forage (42.7% starch; were fed either corn grain plus forage (CD), wheat grain plus forage (WD) or 3 % NaOH-treated wheat plus forage (TWD) during 3 experimental periods: period 1 (P1), which consisted of 7 d of thermoneutral conditions (18 to 21°C and 40 to 50% relative humidity) and 1.7 times maintenance feed intake; period 2 (P2), which consisted of 7 d of HS (28 to 38°C and 30 to 50% relative humidity) and the same feed intake as in P1; and period 3 (P3), which consisted of 7 d of HS as in P2 and 2 times maintenance feed intake in a randomized control experiment. Water was offered ad libitum. The impact of HS was quantified by increases in rectal temperature, respiration rate (RR), and flank skin temperature (FT); variations in blood acid-base balance; and glucose, NEFA, and heat shock protein 70 (HSP-70) plasma concentrations. All physiological variables were elevated during HS, especially when wethers had greater feed intake (P3). Wethers fed CD had lower RR, rectal temperature, and FT than wethers fed WD ( < 0.001) and wethers fed TWD had lower RR and FT than wethers fed WD during HS ( < 0.05). There were reductions in blood CO, HCO3, and base excess concurrent with increases in blood partial pressure of O and pH during HS ( < 0.05). Heat stress reduced plasma NEFA and glucose concentrations whereas it increased prolactin ( < 0.05). Prolactin and HSP-70 plasma concentrations were greater for WD-fed wethers ( < 0.001) associated with Prolactin and HSP-70 plasma concentrations were greater for WD fed wethers (P < 0.001) during HS. These data indicate that the slow rate of rumen fermentation of CD and TWD can reduce the heat released during feed fermentation in the rumen, improving heat tolerance in sheep.

Reducing rumen starch fermentation of wheat with three percent sodium hydroxide has the potential to ameliorate the effect of heat stress in grain-fed wethers,

P. A. Gonzalez-Rivas

Papers

Effects of heat stress on animal physiology, metabolism, and meat quality: A review.

Nutritional strategies to alleviate heat stress in pigs

Effect of feeding slowly fermentable grains on productive variables and amelioration of heat stress in lactating dairy cows in a sub-tropical summer.

Feeding slowly fermentable grains has the potential to ameliorate heat stress in grain-fed wethers

Reducing rumen starch fermentation of wheat with three percent sodium hydroxide has the potential to ameliorate the effect of heat stress in grain-fed wethers,