Timing of Artificial Insemination of Dairy Cows: Fixed Time Once Daily Versus Morning and Afternoon

Nebel, R.L.; Walker, William L.; McGilliard, M.L.; Allen, C.H.; Heckman, G.S.

doi:10.3168/jds.s0022-0302(94)77261-1

Cited by 59 publications

(26 citation statements)

References 16 publications

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“…Once per day insemination was carried out as described by Nebel et al (1994). This protocol and the common accompanying practice of repeating insemination after 24 h may have influenced interservice interval by potentially reducing the preceding or subsequent interval (or both) artificially.…”

Section: Discussionmentioning

confidence: 99%

A description of interestrus and interservice intervals and associated fertility in 16 United Kingdom dairy herds

Greenham¹,

Oikonomou

Grove‐White

2019

Journal of Dairy Science

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Understanding the changes that have occurred in reproductive management and physiology of the dairy cow is necessary to reverse the trend of declining fertility. In this study we analyzed the intervals between estrus events, as detected using tail chalk, in a population of 6,092 dairy cows from 16 herds in the central United Kingdom. Intervals were categorized by absence or presence of an insemination at the first estrus event, being designated interestrus intervals and interservice intervals, respectively. Modal interestrus interval was 21 d, as has been commonly described. Interservice interval was significantly longer than interestrus interval, with a modal value of 22 d. Multivariable analysis identified explanatory variables for intervals between estrus events, with random effects modeling accounting for clustering within herds and within individual cows. Intraclass correlation coefficients indicated that herd identity has a negligible effect, whereas animal identity accounts for 9% of interval variation. Parity, days in milk, insemination at the first estrus of the interval, and interval number within lactation all affected the interval. Logistic regression modeling indicated that interval length is also associated with the outcome of pregnancy. These findings indicate that intervals following an insemination are both longer than previously described and longer than interestrus intervals with no insemination event. The data also suggest that longer interservice interval length may be more conducive to subsequent conception than shorter intervals. Several factors appear to influence interestrus events and further work is required to investigate the underlying physiological mechanisms of these phenomena.

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Section: Discussionmentioning

confidence: 99%

A description of interestrus and interservice intervals and associated fertility in 16 United Kingdom dairy herds

Greenham¹,

Oikonomou

Grove‐White

2019

Journal of Dairy Science

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“…(2005), over 75% of the animals ovulated during a 16‐h time period relative to onset of increased activity and approximately 90% within a period of 32 h. Based on the previous studies assessing the effect of time of AI on pregnancy rate (Trimberger 1948; Hall et al. 1959; Nebel et al. 1994, 2000; Maatje et al.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the larger variability in intervals from activity to ovulation compared with Roelofs et al (2005), over 75% of the animals ovulated during a 16-h time period relative to onset of increased activity and approximately 90% within a period of 32 h. Based on the previous studies assessing the effect of time of AI on pregnancy rate (Trimberger 1948;Hall et al 1959;Nebel et al 1994Nebel et al , 2000Maatje et al 1997;Dransfield et al 1998;Pursley et al 1998;Van Eerdenburg et al 2002;Martinez et al 2004), timing inseminations based on the onset of increased cow activity using this activity meter system is likely to result in an acceptable proportion of inseminations becoming pregnant. In addition, the close association between time of onset of increased activity and time of ovulation suggests that most of the truepositive alerts used in the calculation of sensitivity did not occur by chance alone during a period of low milk progesterone, but were actually temporally associated with ovulation.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a Neck Mounted 2-Hourly Activity Meter System for Detecting Cows About to Ovulate in Two Paddock-Based Australian Dairy Herds

Hockey

Morton

Norman

et al. 2009

Reproduction in Domestic Animals

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Two studies were conducted to assess the performance of a commercially available neck-mounted activity meter to detect cows about to ovulate in two paddock-based Holstein-Friesian dairy herds. The activity monitoring system recorded cow activity count in 2-hourly periods. Study I investigated the ability of the system to detect cow ovulatory periods in dairy herds managed in two different Australian environments and breeding systems using five activity alert algorithms. Herd 1 consisted of approximately 130 milking cows calving year-round in a sub-tropical environment and kept in a single dry lot paddock. Herd 2 consisted of approximately 400 milking cows calving seasonally in a temperate climate and fed pasture by rotation through multiple grazing paddocks. Ovulatory periods and non-ovulatory days were identified using milk progesterone monitoring alone or in combination with ovarian ultrasonography; using these 'gold standards' 141 and 135 ovulatory periods were identified in 64 and 135 cows in Herds 1 and 2 respectively. Sensitivity of the activity monitoring system for detecting cow ovulatory periods ranged from 79.4% to 94.1%, specificity from 90.0% to 98.2% and positive predictive value from 35.8% to 75.8%. Study II investigated the ability of the activity meter system to predict the timing of ovulations in paddock-based pasture-fed dairy cattle (Herd 2). The time of ovulation was estimated by repeat trans-rectal ovarian ultrasonography at approximately 0, 12, 24 and 36 h after artificial insemination (AI). The mean times (± SD) from onset and end of increased activity to ovulation were 33.4 ± 12.4 and 17.3 ± 12.8 h respectively (n = 94). Fifty per cent of cows (n = 47) ovulated within the 8-h period between 30 to 38 hs after the onset of increased activity, 76.6% (n = 72) within the 16 h between 24 to 40 h, 85.1% (n = 80) within the 24 h between 18 and 42 h and 90.4% (n = 85) within the 32 h from 19 to 51 h after the onset of increased activity. Results from these studies show that in paddock-based dairy cows in two diverse management systems, this neck-mounted activity meter system detects high proportions of cows that are about to ovulate and provides a useful indication of when ovulation is likely to occur. However, the specificities and positive predictive values using the algorithms assessed may be lower than desirable.

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“…Timing of AI relative to behavioral estrus in dairy cattle has been an active area of reproductive research for over 50 years because the timing of AI relative to ovulation has a profound effect on pregnancy outcomes after AI (Nebel et al, 1994). Owing to the short lifespan of the oocyte in cattle (Hunter, 2003), the interval from AI to ovulation is critical for optimizing fertility in dairy cows inseminated based on activity associated with estrus.…”

Section: Timing Of Ai Relative To Behavioral Estrusmentioning

confidence: 99%

Expression and detection of estrus in dairy cows: the role of new technologies

Fricke

Carvalho

Giordano

et al. 2014

Animal

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Despite the widespread adoption of hormonal synchronization protocols that allow for timed artificial insemination (AI), detection of estrus plays an important role in the reproductive management program on most dairies in the United States. Increased physical activity is a secondary sign of estrus in dairy cattle, and a new generation of electronic systems that continuously monitor physical activity to predict timing of AI have been developed and marketed to the dairy industry. A variety of management and physiologic challenges inhibit detection of behavioral estrus on farms, but the prevalence of anouvular cows near the end of the voluntary waiting period is particularly problematic. Only 70% of lactating Holstein cows were detected in estrus when using an activity monitoring system, with the remaining 20% of cows classified as anovular and 10% ovulating without showing signs of activity. Mean time of AI in relation to ovulation based on the activity monitoring system was acceptable for most of the cows with increased activity, however, variability in the duration of estrus and timing of AI in relation to ovulation could result in poor pregnancy outcomes in some cows. Use of a Presynch-Ovsynch protocol for submission of cows for first AI has been widely adopted by dairies in the United States, and a combined approach in which AI based on activity is followed by submission of cows not detected with activity to timed AI after synchronization of ovulation may be an effective strategy for submission of cows to first AI. Based on a field trial on a large commercial dairy in the United States, the activity monitoring system detected 70% of cows with increased activity after the second PGF 2α injection of a Presynch-Ovsynch protocol, however, cows inseminated to increased activity had fewer pregnancies per AI (P/AI) compared with cows with increased activity after the second PGF 2α injection that received timed AI after completing the Presynch-Ovsynch protocol. Based on an economic model comparing reproductive management programs with varying levels of AI to estrus v. timed AI, the rate of estrus detection and the P/AI to inseminations based on AI to detected estrus v. timed AI affected the decision to inseminate based on activity v. timed AI. In conclusion, an activity monitoring system detected increased activity in about 70% of lactating Holstein cows on a large commercial dairy in the United States, however, synchronization of ovulation and timed AI was beneficial to inseminate cows not detected with increased activity by the activity monitoring system.

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Timing of Artificial Insemination of Dairy Cows: Fixed Time Once Daily Versus Morning and Afternoon

Cited by 59 publications

References 16 publications

A description of interestrus and interservice intervals and associated fertility in 16 United Kingdom dairy herds

A description of interestrus and interservice intervals and associated fertility in 16 United Kingdom dairy herds

Evaluation of a Neck Mounted 2-Hourly Activity Meter System for Detecting Cows About to Ovulate in Two Paddock-Based Australian Dairy Herds

Expression and detection of estrus in dairy cows: the role of new technologies

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