Back ground: Among various factors that are affecting buffalo productivity, heat stress is challenge for the dairy farmers of Pakistan since the geographical location of Pakistan is sub-tropic as it is situated 23.6 degree above the line of equator between Tropic of Cancer and Tropic of Capricorn and summer season prevail for long duration with high ambient temperature and relative humidity. Information on production potential of mature Nili-Ravi buffalo against hot-dry and hot-humid season and its adaptability to the sub-tropical conditions of central Punjab has not been documented before. In this regard, study is designed to understand the relationships of environmental stress with physiological, behavioral and production responses in Nili-Ravi buffaloes under different housing and cooling conditions.
Hypothesis: Developing and implementing housing and cooling systems to mitigate heat stress may decrease this effect but must be cost effective. To test these hypotheses, the proposed study was carried out at Buffalo Research Institute (BRI).
Methodology: Four experiments were conducted to evaluate the physiological, productive, serum biochemical and behavioral profile of mature Nili Ravi buffaloes under subtropical conditions, at BRI (Buffalo Research Institute), Pattoki. Experiments were conducted during proposed duration of March-April; May-June; July-August and September-October on various physiological and productive parameters. Lactating Nili Ravi buffaloes (n=20) were divided in to four groups with five animals in each group. Group A buffaloes were kept under roof shades
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only (control). Group B was supplemented with yeast powder under roof shade; C group buffaloes were raised under ceiling fans and group D was treated with ceiling fans and showers.
During all summer periods, fans with showers (D) showed highest milk production followed by fans only (C), then control A and B have been similar for most of times. However, in early summer (March-April), the additional cost of supplement feed and cooling strategies was higher than revenue generated from increased milk. Cost per liter of milk produced was higher and thus marginal revenue was lower than expected. Whereas, shaded group A showed comparatively less milk production which was offset by low production cost as there were no additional costs of supplementing feed or cooling strategies.
In all other periods of mid-summer (hot-dry: May-June and hot-humid: July-August) and late summer (July-August), higher milk production was noticed in group D followed by group C despite additional costs of cooling strategies. Lower cost/ liter of milk were noticed as well as high marginal revenue. During these periods, fans were noticed as more effective strategy to alleviate thermal load compare to supplemental feed as cost per liter was high and marginal revenue was less in group B. Looks like feed additive may only be applicable in early summer compare to fans group but shaded group A had best performance in terms of cost per liter and revenue. Group D was found best followed by C in terms of lower cost per liter and high marginal revenue in mid and late summer.
Statistical Analysis: The recorded data was subjected to statistical analysis by using analysis of variance technique (ANOVA) under completely randomized design (CRD). The difference of means among treatment groups were determined by using Duncan Multiple Range Test (DMRT;
SUMMARY
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Steel et al., 1997) for the interpretation of results and portraying conclusions with the help of statistical software (Statistical packages for social sciences; SPSS).
Conclusion: However, it is noted that during March and April control group buffaloes performed better economically but they had lower production and higher physiological responses. Improved performance and health of animals under fans with or without showers did not produce enough marginal income to pay for the additional costs. Shaded group A showed comparatively less milk production which was offset by low production cost as there were no additional costs of supplementing feed or cooling strategies. Therefore, small scale farmers may use shade only for their buffaloes during early summer only but progressive farmers better go for shower and fans strategy since early summer as this approach works best throughout other periods of summer season. Since, the group D was found best followed by C in terms of lower cost per liter and high marginal revenue therefore, fans with showers would be a quite useful technique for progressive farmers and also necessary from animal’s health point of view. Also, small scale farmers may use fans to avoid drastic decrease in milk production and take maximum achievable measures according to their affordability during mid and later summer.