Expression and detection of oestrus in cattle

Abstract

-For herds using AI heat detection rate and calving rate are the two major determinants of compactness of calving, of the proportion of cows that fail to conceive in a defined breeding season. Numerous factors affect the expression of heat including, housing arrangement, floor surface, feet and leg problems and status of herd mates. The number of mounts a cow receives increases with the number of cows that are in heat simultaneously up to about 3-4 cows in heat. Generally, cows that are themselves in heat, coming into heat or were recently in heat are most likely to mount a cow that is in heat. Cows that are at the mid-stages of their cycles (day 5 to about day 16) are least likely to mount a cow that is in heat and consequently could be termed "poor heat detectors". Similarly, cows that are pregnant show less interest in mounting other cows that are in heat. In smaller herds and as more cows become pregnant the likelihood of more than one cow being heat on any given day becomes less, consequently, making heat detection more difficult. The single most important factor affecting heat detection efficiency is that those responsible for checking for heat should fully understand the signs of heat and be fully committed to heat detection for as long as it is planned to use AI. Technological aids to improve heat detection include the use of tail paint, oestrous synchronisation, vasectomised bulls, pressure activated heat mount detectors, radio telemetric devices, pressure sensitive mount count devices and pedometers. As herd size increases and labour become more expensive there will be a greater adoption of some of these technological aids. heat / detection / cattleRésumé -Manifestation et détection de l'oestrus chez les bovins. Dans les élevages où l'on utilise l'insémination artificielle (IA) les taux de détection des chaleurs et de mises bas sont les deux déterminants majeurs du rapprochement des mises bas et de la proportion de vaches qui ne conçoi-vent pas dans une période définie de reproduction. La manifestation des chaleurs est affectée par de nombreux facteurs incluant, la surface du sol, les problèmes de membres et de pieds et l'état des congénères. Le nombre de montes que subit une vache augmente avec le nombre de femelles en chaleurs simultanément, jusqu'à 3-4 vaches. En général, les vaches en chaleur, sur le point de l'être ou qui viennent de l'être sont moins propices à monter une autre femelle en chaleur. Les vaches qui sont en milieu de cycle (J5 à J16) ont peu de chance d'en monter une autre et pourraient donc, être dénommées « faible détectrices de chaleurs ». De façon similaire, les vaches gestantes montrent moins d'intérêt dans la monte que d'autres vaches en chaleurs. Dans les troupeaux plus petits et plus il y a de vaches gestantes, la probabilité pour que plus d'une vache arrive en chaleurs à un jour

A longitudinal study of oestrous characteristics and conception in tie-stalled and loose-housed Swedish dairy cows

“…The frequencies of mountings, STBM and the oestrus duration can also be affected by the floor surface. A concrete and very coarse floor can decrease the mounting activity by 50% and the oestrus duration by 25% compared with cows at a softer floor (Diskin & Sreenan, 2000). The use of activity transponders is increasing in herds with loose-housed cows but can only detect primary and secondary oestrous symptoms.…”

“…This period, referred to as the receptive phase of oestrus or the true oestrus, is regarded as the primary symptom of oestrus (Hurnik et al, 1975;Hurnik, 1987). The primary oestrous symptoms stand to be mounted (STBM) and lowering of the back are accompanied by secondary symptoms such as mounting, anogenital sniffing, chin resting, anxiety, licking and rubbing, all of which are regarded as less accurate because they can occur during other periods of the oestrus cycle than the receptive phase (Diskin & Sreenan, 2000;Kerbrat & Disenhaus, 2004;Roelofs et al, 2010). Moreover, there are a number of local genital symptoms, such as swelling and redness of the vulva as well as vulvar discharge, that are highly associated with oestrus (Stevenson et al, 1983).…”

“…Tied cows express sexual receptivity by lowering their backs and raising their tails upon contact with a neighbour animal or with the herdsman (Gustafsson, 1984;Hurnik, 1987). The receptive phase is preceded by a pre-receptive phase, a period of increasing secondary and local symptoms, and is followed by a post-receptive phase characterized by diminishing oestrous symptoms (Hurnik, 1987;Diskin & Sreenan, 2000). The characteristics of the pre-and post-receptive phases have been given very little attention in recent studies despite their practical importance for oestrus detection.…”

“…Many reports have described the incidence and duration of different oestrous symptoms (for a review, see Diskin & Sreenan 2000;Roelofs et al, 2010). However, most studies assess a limited number of cows under experimental conditions, typically of the Holstein breed, in loose-housing systems.…”

Central genomic regulation of the expression of oestrous behaviour in dairy cows: a review

“…Using cow information, reproductive dynamics and economics representative for the dairy situation in the Netherlands, Inchaisri et al (2010) predicted that an improvement in the oestrus detection rate from 0.30 to 0.50 and from 0.50 to 0.70 will reduce the net economic loss by €53.29 and €11.20 per cow per year, respectively. Various oestrus detection methods aimed at improving detection rate have been developed, evaluated and compared (Diskin and Sreenan, 2000;Firk et al, 2002;Roelofs et al, 2010;Holman et al, 2011). Despite this, modern dairy farming would substantially benefit from an improved oestrus detectability via an increased expression of oestrous behaviour in cows, that is, if cows would generally show the various signs of oestrus during a longer period of time and at a higher intensity and if more cows would show standing oestrus.…”