Genetics of early and lifetime annual reproductive performance in cows of two tropical beef genotypes in northern Australia

Johnston, David; Barwick, Stephen; Fordyce, Geoffry; Holroyd, R. G.; Williams, Patrick James; Corbet, N. J.; Grant, T

doi:10.1071/an13043

Cited by 48 publications

(39 citation statements)

References 44 publications

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“…Extended PPAI result in cows failing to conceive in restricted mating systems or calving out of season or in alternate years in continuous mating systems (Entwistle 1983;Burns et al 2010). The productivity of a beef enterprise is therefore directly affected by the PPAI, which is a heritable trait that can be improved by genetic selection (Johnston et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Using Walk-over-Weighing technology for parturition date determination in beef cattle

et al. 2018

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Abstract. The northern Australian beef industry is dominated by cow-calf operations where reproductive efficiency is a major profit driver. The postpartum anoestrus interval is a major contributor to an animal's reproductive efficiency and is influenced by genetic selection. The genetic trait that measures an animal's postpartum anoestrus interval is the days to calving estimated breeding value and a key requirement is knowledge of the cow's calving date. Traditionally calving date is recorded using laborious and costly methods that are impeding the recording and hence the accuracy of genetic predictions for this trait by the northern Australian seedstock industry. The present experiment used Walk-overWeighing technology to automatically record animal weights as cattle enter a restricted area where they access water. With the use of a novel method to accurately assess weights, the growth paths of cows were tracked from late gestation to post-calving. The calving date was visualised in the growth paths of most cows (78.3%) and a custom algorithm was able to automatically detect the calving date within 10 days of the observed calving period for 63% of cows. The use of Walk-over-Weighing to record calving date provides the opportunity to increase the recording of the days to calving estimated breeding value in the northern seedstock industry, thereby increasing reproductive efficiency and improving the profitability of northern beef producers.

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Section: Introductionmentioning

confidence: 99%

Using Walk-over-Weighing technology for parturition date determination in beef cattle

et al. 2018

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“…It was also clearly indicated in the study of genetics of early and lifetime annual reproductive performance on Brahman and tropical composites cows in northern Australia that reproductive performances from the second mating were largely influenced by lactation anoestrus (Johnston et al 2014). The days to first ovulation after parturition has not been well described in Bali cattle and earlier chapters (2, 3 and 4) outlined some of these features.…”

Section: Introductionmentioning

confidence: 97%

“…A low level of expression of oestrous behaviours results in low oestrous detection rates and longer calving intervals and fewer calves born (Lyimo et al 2000), which will reduce earlyin-life reproduction traits and the overall lifetime reproductive performance of an animal (Johnston et al 2014). Therefore, successful AI and hand mating programs require accurate oestrous detection; poor oestrous detection will contribute to significant economic losses (Heersche & Nebel 1994).…”

Section: Oestrous Detectionmentioning

confidence: 99%

Post-partum Anoestrus in Bali cattle under low-input animal production systems in Eastern Indonesia

Mumu¹

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Bali cows (Bos javanicus) are a common breed in Indonesia and are favoured by smallholders for their size and ease of husbandry. However reproduction rates can be low in some areas and poor nutritional and reproductive management including poor mating management, low availability of genetically superior bulls, poor oestrous detection, poor Artificial Insemination (AI) procedures and poor availability of inseminators at the proper time are crucial issues which are likely to affect this. This thesis examined factors affecting post-partum anoestrus (PPA) and inter-calving interval (ICI) in Bali cows and heifers. This was examined by using large data sets to identify the factors which affect pregnancy rates in villages, developing methods to detect oestrus and pregnancy in villages, examining the effect of body condition score (BCS) on hormonal patterns and by quantifying milk production in cows.A large scale analysis of records from across the eastern islands of Indonesia indicated that there was a median inter-calving interval of 380 days but that postpartum anoestrus could not be determined precisely because of poor observations of first return to oestrus and mating. These records used observational data over 2-4 years where cows under various village management procedures were observed for weight, BCS and at least dates of calving from which various reproductive parameters could be calculated. ICI proved to be most useful and accurate given the quality of observed data. The range in ICI was very large and low annual calving % were recorded. There was an association of high reproduction rate with body condition score (BCS) at calving such that a BCS >3.5 (out of 5) was associated with intercalving intervals of approximately 380 days. The median ICI across all sites was 380 days but some sites recorded 75 percentile values in excess of 500 days.In controlled pen experiments, faecal progestogens and vaginal electrical conductivity were examined as techniques to detect oestrus and pregnancy in the field. Faecal progestogens could be used successfully but there were problems with vaginal electrical conductivity in routine application and this requires more work. Cycling heifers were observed over complete cycles and plasma progesterone and faecal progestogens examined every 2 days. The pattern of faecal progestogen iii concentration over an oestrous cycle mirrored that of plasma progesterone and hence could be used to monitor the oestrous cycle and pregnancy but the sensitivity was low and a number of samples would need to be taken to detect the cycling pattern and/or pregnancy. Similarly cows were monitored over the oestrous cycle and vaginal electrical conductivity measurements made but the association was not strong or sensitive enough to be used routinely. Associations between plasma leptin or plasma IGF-1 concentration and BCS were examined in another controlled pen experiment and plasma IGF-1 concentration was increased in response to higher BCS but plasma leptin concentration was not affected. Heifers ...

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“…The associated effects of lactation are confounded by breed (Baker 1969;Johnston et al 2013), BCS at calving (Montiel and Ahuja 2005), time of calving and the associated effects of postpartum nutrition and energy balance. Any studies assessing the impact of lactation need to partition the effects of other confounding factors to allow an independent assessment of lactation.…”

Section: Lactationmentioning

confidence: 99%

“…Measures describing pregnancy based on time of event data such as time to pregnancy from calving or mating start date (Johnston and Bunter 1996;Johnston et al 2013) and interval from calving to subsequent calving (inter-calving interval) have been used to describe reproductive performance.…”

Section: Measures Based On Time From Event Datamentioning

confidence: 99%

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

McCosker¹

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Approximately half of Australia's beef breeding herds are located in northern Australia with reproductive performance being identified as having a significant impact on the profitability of these businesses. Although many of the risk factors affecting the reproductive performance of beef cattle have been previously identified, the relative contribution of major risk factors to key measures of performance, after partitioning the effects of other confounding variables, is lacking, particularly for extensive tropical rangeland systems typical of northern Australia.The overall objective of the research described in this thesis was to, i) describe the reproductive performance of commercial beef breeding cattle in northern Australia and, ii) determine, and quantify the effect of the major risk factors associated with three key measures of reproductive performance (lactating cows becoming pregnant within 4 months of calving, cows failing to become pregnant within an approximate 12 month reproductive cycle, and foetal/calf loss between confirmed pregnancy and weaning). It was hypothesised that the major risk factors determining the probability of lactating cows becoming pregnant within four months of calving are similar to those determining the probability of foetal/calf loss between confirmed pregnancy and weaning. To address these objectives, a prospective population-based epidemiological study was conducted between 2007 and 2011 involving 78 commercial beef properties located across northern Australia.Attainable and typical levels of reproductive performance for cow-age cohorts were described using a dataset containing 114,154 annual production cycles of performance data that represented approximately 78,000 heifers and cows managed in 142 breeding groups. Properties were assigned to one of four broad country types following a subjective assessment of the production potential of the grazing land and cross-referencing with pasture and vegetation descriptions reported by the herd owners/managers.The typical overall reproductive performance of cows in the Northern Forest (57 live calves at muster per 100 surviving mature cows), was considerably lower than that for the other country types (71-83 live calves at muster per 100 surviving mature cows). This was due to typically much lower percentage of cows becoming pregnant within 4 months of calving, higher foetal and calf loss and higher estimated mortality of pregnant cows in the Northern Forest compared to the other genotypes. These findings are consistent with the generally poorer quantity and quality of pasture, ii harsher environment and higher disease risk of cattle managed in the Northern Forest compared to the other country types.Country type and predicted calving period were top-order determinants of pregnancy within 4 months of calving while lactating. The effect of cow-age class cohort was dependent on country type with the expected occurrence of lactating cows pregnant within 4 months of calving estimated to be 23. 1-53.8, 38.1-61.6, 35.4-56.5 and 38.5...

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Genetics of early and lifetime annual reproductive performance in cows of two tropical beef genotypes in northern Australia

Cited by 48 publications

References 44 publications

Using Walk-over-Weighing technology for parturition date determination in beef cattle

Using Walk-over-Weighing technology for parturition date determination in beef cattle

Post-partum Anoestrus in Bali cattle under low-input animal production systems in Eastern Indonesia

Risk factors affecting the reproductive outcome of beef breeding herds in North Australia

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