Calving patterns in seasonal & split calving herds
InCalf's messages
The InCalf Book recommends that most cows should calve during the first 6 weeks of the calving period in seasonal and split calving herds. Cows that calve later in the calving period have shorter calving to mating start date intervals and are difficult to get in calf. Excessive numbers of late calving cows reduce herd reproductive performance substantially. See pages 149-150 of The InCalf Book.
What the current scientific literature says
Reproductive performance during a seasonal mating program is substantially better amongst cows with longer intervals from calving to mating start date.
Reproductive performance assessed from mating start date is substantially better amongst cows with longer intervals from calving to mating start date. In New Zealand research in seasonal calving herds, cows with short intervals to mating start date were at increased risk of involuntary culling (Harris 1989) and were much less likely to be pregnant by 30 days after mating start date (McDougall 2001). Similar (high) proportions were pregnant in both groups after 80 days of mating (McDougall 2001) in contrast to an Australian study in seasonal calving herds where a very strong association was observed between time from calving to mating start date and proportion of cows pregnant by specified time periods from mating start date up to 150 days (Brightling et al 1990). This Australian study also demonstrated a curvilinear relationship between voluntary waiting period and reproductive performance. For every extra 20 days that time from calving to mating start date was prolonged between 0 and 59 days, the proportion pregnant after 150 days of mating increased by 4-5%, in comparison with increases of only 1-3% for every extra 20 days mating start date was prolonged from 60 days after calving. A strong curvilinear association was also reported in the InCalf research.
These effects are due to both higher submission and conception rates amongst cows with longer intervals from calving to mating start date. With increased time from calving, cows are increasingly likely to be detected in oestrus and inseminated (Berger et al 1981). Conception rates are also strongly associated with calving to service interval. Numerous studies have reported low conception rates to services soon after calving, with higher conception rates occurring between 100 and 200 days after calving (Arnott 1961; Whitmore et al 1974; Williamson et al 1980; Berger et al 1981; Dohoo 1983; Hillers et al 1984; Reimers et al 1985; Ferguson 1991; Hodel et al 1995; Ferguson 1996; Thompson et al 1996; Dransfield et al 1998; Royal et al 2000; Mayne et al 2002). This relationship seems curvilinear, with largest incremental increases in conception rate occurring sooner after calving. Smaller increases are reported after day 40 (Stevenson et al 1983). These increases in conception rate are similar amongst both clinically healthy cows and cows diagnosed with various diseases in early lactation (Dohoo 1983) but may be larger where negative energy balance in early lactation is more extreme (Ferguson et al 1989) and amongst multiparous cows (Schindler et al 1991).
Longer calving to service intervals are associated with increased likelihood of one or more pre mating ovulations (Macmillan and Clayton 1980; Stevenson and Call 1983; Senatore et al 1996) as well as increased time from calving per se and both components may act independently to cause the positive relationship between calving to service interval and conception rates (Macmillan and Clayton 1980). Time from calving to service is directly associated with conception rates as well as indirectly via metabolic risk factors (Moss 2001), suggesting that correcting nutritional factors may reduce but not eliminate this relationship. Lower conception rates following insemination soon after calving are due in part to increased risk of embryonic mortality (Ball and Morant 1978).
Effects of very long calving to mating start date intervals (100 days or more) on reproductive performance are not consistent. In a Swedish intervention study, cows in two herds were allocated a voluntary waiting period (the equivalent of calving to mating start date interval) of either 50 days or 140 days (herd 1) or 230 days (herd 2). In herd 1, amongst cows allocated the longer voluntary waiting periods, conception rates were higher and fewer cows remained non-pregnant by 130 days after mating start date (Ratnayake, 1998 #1136;Larsson, 2000 #1207). In herd 2, these differences were not observed in the first lactation (Ratnayake, 1998 #1136) and over three years, culling for infertility per lactation was similar amongst both groups of cows (Osterman, 2003 #1125). Similarly estimated proportions of non-pregnant cows becoming pregnant in each 3 weeks of the mating period were similar for cows allocated either a 60 or 150 day voluntary waiting period (Amburgh, 1997 #184). This may be due to reductions in conception rates amongst cows where calving to service interval was very long as has been observed in several studies (Arnott 1961; Dohoo 1983; Hodel et al 1995; Thompson et al 1996; Loeffler et al 1999a; Loeffler et al 1999b) although selection bias may also explain these associations.
Compiled by Dr John Morton
References
Arnott WJ (1961) Problems of artificial breeding of cattle. Australian Veterinary Journal 36: 140-145
Ball PJH and Morant SV (1978) Factors affecting the incidence and timing of embryo losses in dairy cattle. Animal Production 26: 357-358
Berger PJ, Shanks RD, Freeman AE and Laben RC (1981) Genetic aspects of milk yield and reproductive performance. Journal of Dairy Science 64: 114-122
Brightling P, Larcombe MT and Malmo J (1990) Investigating shortfalls in reproductive performance in dairy herds. Dairy Research Council, Australia,
Dohoo IR (1983) The effects of calving to first service interval on reproductive performance in normal cows and cows with postpartal disease. Canadian Veterinary Journal 24: 343-346
Dransfield MBG, Nebel RL, Pearson RE and Warnick LD (1998) Timing of insemination for dairy cows identified in estrus by a radiotelemetric estrus detection system. Journal of Dairy Science 81: 1874-1882
Ferguson JD (1991) Nutrition and reproduction in dairy cows. Veterinary Clinics of North America, Food Animal Practice 7: 483-507
Ferguson JD (1996) Diet, production and reproduction in dairy cows. Animal Feed Science and Technology 59: 173-184
Ferguson JD, Foote RH, Eger S, Reimers TJ, Schindler H and Amir S (1989) The influence of cumulative negative energy balance on conception with time post partum in dairy cows. Journal of Dairy Science 72 (Suppl 1): 417-418
Harris BL (1989) New Zealand dairy cow removal reasons and survival rate. New Zealand Journal of Agricultural Research 32: 355-358
Hillers JK, Senger PL, Darlington RL and Fleming WN (1984) Effects of production, season, age of cow, days dry, and days in milk on conception to first service in large commercial dairy herds. Journal of Dairy Science 67: 861-867
Hodel F, Moll J and Kuenzi N (1995) Analysis of fertility in Swiss Simmental cattle - genetic and environmental effects on female fertility. Livestock Production Science 41: 95-103
Loeffler SH, de Vries MJ and Schukken YH (1999a) The effects of time of disease occurrence, milk yield, and body condition on fertility of dairy cows. Journal of Dairy Science 82: 2589-2604
Loeffler SH, de Vries MJ, Schukken YH, de Zeeuw AC, Dijkhuizen AA, de Graaf FM and Brand A (1999b) Use of AI technician scores for body condition, uterine tone and uterine discharge in a model with disease and milk production parameters to predict pregnancy risk at first AI in Holstein dairy cows. Theriogenology 51: 1267-1284
Macmillan KL and Clayton DG (1980) Factors influencing the interval to post-partum oestrus, conception date and empty rate in an intensively managed dairy herd. Proceedings of the New Zealand Society of Animal Production 40: 236-239
Mayne CS, McCoy MA, Lennox SD, Mackey DR, Verner M, Catney DC, McCaughey WJ, Wylie ARG, Kennedy BW and Gordon FJ (2002) Fertility of dairy cows in Northern Ireland. Veterinary Record 150: 707-713
McDougall S (2001) Effects of periparturient diseases and conditions on the reproductive performance of New Zealand dairy cows. New Zealand Veterinary Journal 49: 60-67
Moss N (2001) The epidemiology of subfertility in Australian dairy cows. Ph D thesis, University Veterinary Centre - Camden, Faculty of Veterinary Science, University of Sydney, Sydney
Reimers TJ, Smith RD and Newman SK (1985) Management factors affecting reproductive performance of dairy cows in the Northeastern United States. Journal of Dairy Science 68: 963-972
Royal MD, Darwash AO, Flint APF, Webb R, Woolliams JA and Lamming GE (2000) Declining fertility in dairy cattle: changes in traditional and endocrine parameters of fertility. Animal Science 70: 487-501
Schindler H, Eger S, Davidson M, Ochowski D, Schermerhorn EC and Foote RH (1991) Factors affecting response of groups of dairy cows managed for different calving-conception intervals. Theriogenology 36: 495-503
Senatore EM, Butler WR and Oltenacu PA (1996) Relationships between energy balance and post-partum ovarian activity and fertility in first lactation dairy cows. Animal Science 62: 17-23
Stevenson JS and Call EP (1983) Influence of early estrus, ovulation, and insemination on fertility in postpartum Holstein cows. Theriogenology 19: 367-375
Stevenson JS, Schmidt MK and Call EP (1983) Factors affecting reproductive performance of dairy cows first inseminated after five weeks postpartum. Journal of Dairy Science 66: 1148-1154
Thompson JA, Magee DD, Tomaszewski MA, Wilks DL and Fourdraine RH (1996) Management of summer infertility in Texas Holstein dairy cattle. Theriogenology 46: 547-558
Whitmore HL, Tyler WJ and Casida LE (1974) Effects of early postpartum breeding in dairy cattle. Journal of Animal Science 38: 339-346
Williamson NB, Quinton FW and Anderson GA (1980) The effect of variations in the interval between calving and first service on the reproductive performance of normal dairy cows. Australian Veterinary Journal 56: 477-480