Sunil Kumar S. V. Singh Jyoti Kumari Vol 8(5), 229-238 DOI- http://dx.doi.org/10.5455/ijlr.20170911110324
Indirect calorimetry was used to estimate metabolic heat production and methane energy loss from Tharparkar and Karan Fries (Holstein Friesian × Tharparkar) cattle in tropical climate by putting the animals in respiration calorimeter chamber. In the present study, Concentration of CH4, O2 and CO2 were measured in ambient air as well as in outlet air from the chamber by keeping the animals inside them. The data were recorded after 1 hours of feeding continuously for 6 hours at the interval of 1 minute for five days to decrease the random error. Physiological responses i.e. respiration rate and heart rate was significantly whereas rectal temperature was non significantly higher in Karan Fries as compared to Tharparkar cattle. Metabolic heat production and methane emission was significantly higher in Karan Fries (9.43 kcl/min & 122.93 L/day) than Tharparkar (4.72 kcal/min & 40.01 L/day) respectively. The finding of study showed the better adaptability of zebu breeds to tropical climatic condition in terms of metabolic heat and methane production as compared to crossbred cattle.
Keywords : Heat production Karan Fries Methane Physiological Tharparkar
Introduction
Dairy cattle are sensitive to heat stress due to metabolic heat production associated with rumen fermentation and methane emission. The metabolism of an animal is always in a state of dynamic equilibrium in which the influx of nutrients is balanced by the production of energy in catabolic and anabolic processes. The animal body is like a furnace, which burns fuel in the form of metabolites produced from feedstuffs and uses the energy for different activities such as milk synthesis, muscle growth, etc.
Basal metabolism has been defined as the minimal energy cost when an animal is at rest in a thermoneutral environment and in a post-absorptive condition (Brody, 1945). The post-absorptive condition is necessary to reduce the possible heat production that can be attributed to the heat of fermentation of food or nutrient metabolism. The energy required to maintain life at the basal metabolic rate used for circulation, excretion, secretion, respiration activities, and the maintenance of muscle tone. The measurement of the metabolic heat production in dairy animals is based on two methods. In direct measurements of the metabolic rate involve the measurement of the actual heat production by the animal. In this heat energy given off by an animal and energy in the ingested food (Hoar, 1966) is calculated by placing animals in a closed box surrounded by ice and recording the amount of ice that melted in a specified period of time. In indirect measurements of heat production, the calculation of metabolic heat production is based on amount of oxygen consumed and the amount of carbon dioxide and methane produced by the animal, this method is simpler and less expensive than the direct methods. During the present study, indirect method was used and this method has several advantages i.e. the animals are confined in a small chamber and the oxygen, carbon dioxide and methane content of the air leaving the chamber is measured and compared with that of composition of the ambient air entering the chamber.
Methane production through enteric fermentation by ruminants is a growing concern in countries around the world due to its contribution to accumulating green house gases (GHG) in the atmosphere. Methane production should also be of concern to livestock producers and nutritionists, because the production of CH4 represents a loss of energy from feedstuffs that could have been used for growth and production of the animal. Respiration calorimetry is the method of choice that has been used to generate a majority of existing data on methane production by various types of cattle under various dietary conditions (Pickering et al., 2013). Keeping in view the above facts in mind present study was conducted in growing Tharparkar and Karan Fries cattle.
Materials and Methods
Selection and Feeding of Animals
Five each of Tharparkar (TP) and Karan Fries (KF) growing cattle were selected from Livestock Research Centre of ICAR-National Dairy Research Institute, Karnal (India). Karnal lies on the geographical coordinates of 29°41’0″N, 76°59’0″ E. The animals were provided ad-lib mixed ration prepared using concentrate-30 parts, maize fodder-40 parts and wheat straw-30 parts. Concentrate mixture comprised of maize (31 parts), groundnut cake-solvent extracted (10 parts), mustard cake-solvent extracted (10 parts), wheat bran (20 parts), deoiled rice bran (16 parts), cotton seed cake (10 parts), mineral mixture (2 parts) and salt (1 part). The fresh clean drinking water was provided round the clock during entire experimental period. The animals were given an adaptation period of 15 days before the starts of actual experiment.
Indirect Respiration Calorimetry
Prior to actual experiments, animals were kept in calorimetric chamber for 15 days for adaptation, so that dry matter intake (DMI) measured outside and inside the chamber remained unaltered. The dimensions of calorimetric chambers are of 8.5 ft (width) × 8.25 ft (height) × 13.3 m (ft) length. A picture of the respiration chamber, analyzer and software for data recording is shown in Fig. 1.
A |
D |
C |
B |
Fig.1: (A) Respiration chamber; (B) Multi gas system; (C) Multi gas Analyzer, (D) Software for data recording
Pump is attached to thrust air from the chamber through a flow meter followed by various gas sensors for CO2, O2 and CH4. Fresh air into the chamber is drawn from outside through an inlet fixed at the roof corner above head of the animal. Chamber walls are formed of transparent acrylic sheets so that animal in a chamber can see surrounding animals in other chambers to avoid fear and thus encourage normal feed intake, behaviour and metabolism. For calibration, nitrogen gas was passed through the sensor to set the values of all the gases (CH4, O2 and CO2) at zero level which is known as low calibration. To standardize the analyzer, high calibration was done using the following concentration of gases viz. O2-20.95%, CO2-9169 ppm and CH4-9089 ppm. Concentration of CH4, O2 and CO2 were measured in ambient air as well as in outlet air from the chamber by keeping the animals inside them. The data were recorded after 1 hours of feeding continuously for 6 hours at the interval of 1 minute for five days to decrease the random error. Inside the respiration chamber, a platform was there on which animal stands and which is equipped with a sliding tray below for collection of urine.
Physiological Responses
The metabolic heat production is correlated with measuring the variation of rectal temperature (RT), respiratory rate (RR) and heart rate (HR) of the animals. Heart rate and respiration rate were recorded by counting the inward and outward movement of the flank and counting the pulsation of middle coccygeal artery at the base of the tail respectively. The rectal temperature (RT) was recorded by using clinical thermometer, which was inserted into the rectum of the animals, which remained in contact with the mucous membrane at least 1-2 minutes.
Calculation of Different Gases at Ambient Temperature Pressure at Saturated Air (ATPS)
The volume of oxygen consumption, carbon dioxide and methane production was calculated using the following formula as described by (Kumar et al., 2016).
The Rate of Volume of Expired Air was Calculated from Formula
Air flow rate (AFR) = 400 L/min (measured by air flow meter)
Air flow meter reading was taken as VE (STPD) (L/min) (1)
Oxygen Consumption
Rate of O2 consumption was calculated from formula–
VO2 (ATPS) (liter/min) = VE × (FIO2 – FEO2) (2)
(1- FEO2)
Where,
VO2 = the rate of oxygen consumption,
VE = The volume of air the subject breathes in one min (minute volume),
FIO2 = The fraction (percentage divided by 100) of inspired air that is oxygen i.e. 0.2094 (Since the percentage of oxygen in room air is constant at about 20.94%)
FEO2 = The fraction of expired air that is oxygen (i.e., the percentage measured with the O2 analyzer).
Carbon Dioxide Production
The Volume of CO2 produced per min was calculated using formula-
VCO2 (ATPS) (liter/min) = VE × (FE CO2 – FI CO 2) – FI CO2 × VO2 (3)
(1 – FI CO2)
Where,
VCO2 = the rate of carbon dioxide production.
VE = the volume of air the subject breathes in one min (minute volume).
FECO2 =the fraction of expired air that is carbon dioxide.
FI CO 2 = the fraction (percentage divided by 100) of inspired air that is carbon dioxide i.e.
FICO2 = 0.0003 (Since a little percentage (0.03%) of CO2 in fresh air).
Methane Production
The volume of CH4 produced per min was calculated:
VCH4 (ATPS) (liter/min) = VE × FECH4 (4)
Where,
VCH4 = the rate of methane production.
VE = the volume of air the subject breathes in one min (minute volume).
FE CH4 = the fraction of expired air that is methane.
Calculation of Different Gases at Standard Temperature and Pressure of Dry Air (STPD)
The VE, VO 2, VCO2, VCH4 for STPD was obtained from respective VE, VO 2, VCO2, and VCH4 for ATPS by using following formula–
VE (STPD) (liter/min) = VE (ATPS) ×0.825 (5)
VO 2 (STPD) (liter/min) = V E (STPD) (FIO2 – FEO2) (6)
VCO2 (STPD) (liter/min) = VE (STPD) (FECO2 -FI CO2) (7)
VCH4 (STPD) (liter/min) = VE (STPD) × (FE CH4) (8)
Metabolic Heat Production
Metabolic heat production (Kcal) was determined accurately from oxygen consumption, carbon dioxide and methane production. The following formula was used to determine metabolic heat production-
H=3.866×O2+1.200×Co2 – 0.518×CH4 (Brouwer, 1964)
Where,
H= Metabolic heat production (Kcal)
O2 =oxygen consumption (liters)
CO2= carbondioxide (liters)
CH4 = Methane production (liters)
Energy Loss as Methane
The energy loss as methane was calculated using the following formula-
Energy loss as methane = 9.45 X VCH4 (STPD) (liter/min) (Santoso et al., 2007)
Statistical Analysis
Data were analyzed using one way analysis of variance (ANOVA) by Statistical Analysis System (SAS, 2011) Software Programme, version 9.1 and results were expressed as mean ± SE. P<0.05 was considered statistically significant.
Results and Discussion
Physiological Responses
The result of Physiological responses i.e. rectal temperature (RT), heart rate (HR) respiratory rate (RR) in Tharparkar and Karan Fries growing cattle are presented in Table 1. Respiration rate (RT) of Tharparkar was numerically lower than Karan Fries, whereas heart rate (HR) and respiration rate (RR) of Tharparkar was lower than Karan Fries.
Respiration rate is the first physiological measure that increases when the animal undergoes heat stress and eliminating high metabolic heat production and showing greater variation than the other physiological responses like rectal temperature and heart rate. Tharparkar animals showed lower physiological responses (RT, RR & HR) than Karan Fries which might be due to lower metabolic rate and higher sweating rate.
Table 1: Physiological responses of Tharparkar and Karan Fries heifers
Parameters | Tharparkar | Karan Fries |
Rectal temperature (ºC) | 102.34 ± 0.01a | 102.47 ± 0.15a |
Respiration rate (bpm) | 21.2 ± 0.58a | 24.4± 0.74b |
Heart rate (BPM) | 72.2 ± 0.8a | 74.4 ± 0.67b |
Means showing different superscripts in row differs significantly at 5% (P<0.05)
Kellaway and Colditz, (1975) found that the RR and RT of Bos taurus animals were significantly higher compared to crossbred and Zebu animals. During periods of stress, an animal exposed to the sun has a higher radiating heat load than its metabolic heat production. Studies have showed higher rectal temperature and respiratory rate of animals exposed to the sun than those in the shade. Excess heat production during summer leads to activation of evaporative heat loss mechanisms involving an increase in sweating rate and respiratory minute volume, (Al-Haidary et al., 2001) which causes increase in respiration rate. About 70–85% of maximal heat loss via evaporation is due to sweating with the remainder due to respiration (Finch, 1986). Genetic differences exist between zebu and crossbred animals for heat tolerance as Bos indicus breeds are more heat tolerant than Bos Taurus, (Blackshaw and Blackshaw, 1994). Kumar et al. (2017) also reported the breed difference among the physiological responses and found that Sahiwal heifers had lower RT, RR and PR as compared to Karan Fries heifers due to lower metabolic rate.
Metabolic Heat Production
The result of O2 consumption, CO2 and CH4 production and metabolic heat production of Tharparkar and Karan Fries animals have been presented in Table 2. The mean body weight and metabolic body weight (W0.75) of Tharparkar and Karan Fries was not significantly (P<0.01) different. The O2 consumption CO2 and metabolic heat production in Karan Fries were significantly (P<0.05) higher than Tharparkar. Metabolic heat production is attributed to metabolism of an animal, which is always in a state of dynamic equilibrium in which the influx of nutrients is balanced by the production of energy in catabolic and anabolic processes. The differences in O2 consumption, CO2 and CH4 production due to difference in metabolism of different breeds is the determinant for the metabolic heat production. This difference in O2 consumption, CO2 and CH4 production was mainly due to different basal metabolic rate of the different breeds of the animals.
Table 2: Metabolic heat production and energy loss as methane of Tharparkar and Karan Fries heifers in animal calorimetric chamber
Parameters | Tharparkar | Karan Fries |
Body weight (kg) | 210.82±18.42a | 288.5±24.62a |
Metabolic body weight (kg) | 158.11±13.81a | 216.37±18.46a |
VE (STPD) (L/min)(AFM) | 457.2 | 457.2 |
VO2 (STPD) (L/min) | 1.03±0.12a | 2.18±0.27b |
VCO2 (STPD) (L/min) | 0.62±0.02a | 0.86±0.07b |
VCH4 (STPD) (L/min) | 0.02±0.008a | 0.08±0.016b |
HP/min (kcal) | 4.72±0.45a | 9.43±1.01b |
HP/day (kcal) | 6801.55±656.47a | 13584.70±1461.39b |
HP/metabolic body weight (kcal/kg 0.75 ) | 43.98±4.87a | 65.93±11.06b |
Mean% CH4 | 0.021±0.002a | 0.035±0.005b |
CH4 (L/day) | 40.01±12.65a | 122.93±24.23b |
Energy loss as CH4 (kcal/min) | 0.26±0.08a | 0.80±0.15b |
Energy loss as CH4 (kcal/day) | 378.14±119.54a | 1161.70±229.04b |
CH4*9.45 (kcal)/HP (kcal/min) | 5.19±1.38a | 8.65±1.56a |
Means showing different superscripts in row differs significantly at 5% (P<0.05)
Tiwari et al. (2000) reported the O2 consumption, CO2 and CH4 production and heat production per unit body metabolic body weight (kg w0.75) were 17.03 lit, 11.7 lit, 0.12 lit, and 331 KJ respectively for growing buffalo calves fed low quality diet which is attributed to higher energy loss. Boyels et al.(1991) found that metabolic heat production (kcal·kg−75·d−1) was significantly (P<.05) higher in Brahman x Angus steers than the Hereford x Angus steers when breed was the main effect. Kumar et al. (2016) also reported lower metabolic heat production (4.06±0.11 Kcal/min) by Sahiwal as compared to Karan Fries heifers (5.31±0.21 Kcal/min), that confers the better ability of the indigenous breed to withstand the hot humid condition of tropical zone than the crossbred animals. The results of the present study are in accordance to those of Koga et al. (1991) reported higher value of heat production (8.7 kcal/min) in adult buffaloes (510-610 kg) during different temperature conditions. This difference in heat production during present investigation may be probably due to breed difference.
Energy Loss as Methane
The results of methane emission and energy loss as methane in Tharparkar and Karan Fries heifers are presented in Table 2. The levels of energy loss as methane in Tharparkar and Karan Fries heifers differed significantly (P<0.05) being higher in Karan Fries than Tharparkar heifers.
Ruminants have a unique digestive system that allows them to use a wide array of feedstuffs; the rumen is a large anaerobic fermentation vat and home to millions of microorganisms. These microorganisms digest protein and energy substrates of the diet and produce proteins, volatile fatty acid and methane. Methane (CH4) is a loss of dietary energy, which is approximately one-half of the commonly predicted 6% of diet GE. Considerable variation is found among breeds. Staerfl et al.(2012) reported the methane emission rate (7.3 % to 11.5 %) of Brahman cattle that are maintained in a tropical feeding system, while Johnson and Johnson (1995) found a methane energy loss of 6 to 7% of gross energy intake, when forage were fed at ad libitum level. Chaokaur et al. (2015) studied the effect of feeding level on methane energy loss and found 8% and 11.5% energy was loss as methane when animals were maintained on higher and lower quality of feed respectively. The results of the present study are in agreement with Kumar et al. (2016) who reported 10.04%±0.18 and 12.36%±1.02 energy loss as methane in Sahiwal and Karan Fries growing cattle, this energy loss was decreased to 7.85%±0.81 and 9.98%±0.91 respectively when these animals were fed to high energy diets due to better digestibility of feedstuffs and rate of passage with increasing energy level of the feed that decrease the opportunity for degradation of potentially degradable NDF, consequently, methane emission rate is decreased. This study also indicated that the methane emission rate was more in Karan Fries than Sahiwal growing animals indicating that our indigenous breed are more adapted to tropical climatic conditions than the crossbred.
Conclusion
Based on the above findings, it can be concluded that crossbred animals had higher metabolic heat production, methane energy loss and physiological responses as compared to zebu cattle due to greater metabolic rate, which impart higher green house gases to the environment. The lower metabolic rate of zebu breeds indicates the better adaptability of it to tropical climatic condition in terms of heat and methane production.
Acknowledgement
The authors wish to thank Director NDRI and NICRA project for providing the necessary facilities and financial support respectively.
Conflict of Interest
The authors declare that there are no any conflicts of interest.
References