Ibrahim, Mohamed N.M.

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ILRI Pakistan Factsheet—July 2015 1IO.LRI RESEARCH BRIEF  NDate  yearIntroductionAs a result of Artificial Insemination and selection of bulls and cows during the past four decades, Pakistan dairy farmers have achieved significant increases in milk production. However, compared to some countries where the average production is 6000-8000 kg per cow per year, the Pakistan average milk production is much lower. A key factor in improving milk production (after improved feeding) is timely reproduction. Each oestrus which has not been identified beyond 90 days after the last calving causes economic losses: •	 in production of milk •	 additional feed •	 cost for labour •	 loss of animals for replacementThe heat cycleWhat is heat? Heat is a period of acceptance for mating that normally occurs in pubescent heifers and non-pregnant cows. The period of receptivity may last from 6 to 30 hours and occurs on an average every 21 days (18-24 days).Phase 1. Pro-heat – before the oestrusThis phase lasts one or two days, and its characteristics are development and growth of follicles on ovaries, producing small quantities of hormones. Concentration of hormones will determine behaviour of animals: the cow is restless, it moo’s, and there is a clear, transparent excretion of oestrus mucus from the vulva.Phase 2. Heat peak or oestrusWith maturing of so-called ‘dominant’ follicle on ovaries, relatively high quantities of oestrogen are being produced by cells from follicle walls. The cow stands still and allows other animals to mount her; there is more mucus which is clear and transparent.Phase 3. After-heat and ovulationOvulation is bursting of follicles and release of ovum. Release of ovum from follicles occurs approximately 24-30 hours after oestrus. Cows or heifers should be inseminated 12-30 hours after the beginning of oestrus. Identifying oestrusIdentifying oestrus, especially in larger breeding stock, is not a simple job, and it is one of the main obstacles for achieving inter-calving interval of 12 months. Facilities with cows that are to be inseminated should be visited many times, and there are also some cows that do not show obvious external symptoms of heat (so-called «silent oestrus»).Every missed oestrus means an economic loss, because it is directly related to long service period (period from calving until the next diagnosed pregnancy), that is, to inter-calving period. Definitely, each oestrus which had not been identified, and it has been more than 100 days from the last calving, would cause economic losses in production of milk, additional feed, cost for workers, loss of animals for replacement, etc.There could be some mucus even after oestrus. In most of the cases, this mucus contains more or less blood.Oestrus cycle and heat detection in dairy  animals in Pakistan ILRI Pakistan Factsheet 4                                                            July 2015                    ILRI Pakistan Factsheet—July 20152Cow in oestrus is characterized with the so-called standing reflex. It allows other animals to mount it, and in the process, pressure in sacral area affects group of nerves (in spinal cord) which innervate also reproduction system and transmit sensitive stimuli. In that way, typical coital behaviour of cow can be detected.Signs of heatDetection of heat needs careful observation. Cows have a pattern of behaviour that changes gradually from the start to the end of heat. Onset of heat activity follows a distinct pattern, with most activity happening in the late evening, through the night, and late into the early hours of the morning. As such, in order to detect heat cows should be observed carefully in the earlier hours of the morning, and late hours in the evening.•	 Characteristic signs of heat (in cattle) are: •	 Standing to be mounted by other cattle•	 Cow may attempt to mount others•	 Vulva – reddened, swollen and moist•	 Watery mucous hanging from the vulva and adhering to tail and legs•	 Restless•	 Bellowing•	 Frequent urination •	 ‘Raised tail’ is the best sign “for Heifers”•	 Drop in milk production - milking animals•	 Loss of appetiteCharacteristic signs of heat in buffaloEarly heat Mid-heat Late Heat8 hrs 12–18 hrs 18–24 hrsUrination frequency Least More LessBellowing Sometimes Very common NoExcitement More less NormalMounting by teaser Less More LeastAppetite Normal Less NormalMilk yield Normal Less NormalCervix open Partial Full ClosedThe research brief has a Creative Commons licence. You are free to re-use or distribute this work, provided credit is given to ILRI.                     July 2015Remember!!! …. in BuffaloMost noticeable signs of heat are shown clearly during mid-heat, so the chance of missing it is HIGHTime for service or inseminationArtificial insemination or natural service can lead to pregnancy only if the spermatozoa are at the right place at the right time. The egg is released from the ovary about 10 to 14 hours after the end of heat, and can survive unfertilized for 6-12 hours. While the spermatozoa can live up to 24 hours in the reproductive tract of the cow. Best timing of AI: The morning-evening rule•	 cows observed in heat in the morning are inseminated in the afternoon•	 cows observed in heat in the afternoon are inseminated the next morningCauses of low conception rates•	 Problems related to heat detection (not servicing, improper timing)•	 Problems related to AI or natural service (improper AI technique, a bull with low fertility)•	 Cow factors (infections of reproductive duct, hormonal disorders, early embryonic death)•	 Problems related to nutrition (poor nutrition or over feeding resulting in obesity.  An initial version of this factsheet was developed through the Agricultural Innovation Program for Paki-stan. It was made possible by the support of the Ameri-can people through the United States Agency for Inter-national Development (USAID). The contents are the sole responsibility of ILRI and do not necessarily reflect the views of USAID or the United States Government.  It was prepared by M.N.M Ibrahim  (m.ibrahim@cgiar.org).Box 5689,  Addis Ababa, Ethiopia Phone: +251 11 617 2000  Fax: +251 11 617 2001 Email: ILRI-Ethiopia@cgiar.orgilri.org better lives through livestock ILRI is a member of the CGIAR ConsortiumBox 30709, Nairobi 00100, Kenya Phone: +254 20 422 3000 Fax:     +254 20 422 3001 Email: ILRI-Kenya@cgiar.orgBox 5689,  Addis Ababa, Ethiopia Phone: +251 11 617 2000  Fax: +251 11 617 2001 Email: ILRI-Ethiopia@cgiar.org

Oestrus cycle and heat detection in dairy animals in Pakistan

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Oestrus cycle and heat detection in dairy animals in Pakistan

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