Lifetime productivity in gilts previously selected for decreased age at puberty

Abstract

A study was conducted to evaluate the effect of decreasing age of puberty on lifetime productivity in sows. Two lines of gilts from the Nebraska Gene Pool population were used in this study: a line that had been selected for decreased age at puberty (AP) and a line in which selection had been random (RS). The study was conducted in two parts. In part one, 75 gilts were mated at second oestrus and the productivity measured over five parities. A second experiment utilizing 68 gilts was conducted to provide further data for comparing litter size at parity 1, and also to compare ovulation rates in the two lines at second oestrus. Results showed that litter size was similar in both lines across parities. After five parities the percentage of sows farrowing relative to parity 1 was 58-8% for the AP line but only 39-4% for the RS line (P = 0-17). Litter birth weight, litter size and weight at 21 days, number weaned, and lactation food consumption were similar for both lines. Lactation weight loss was not significantly different between the two lines (60-9 (s.e. 5-9) v. 527 (s.e. 5-0) kg, for RS and AP gilts, respectively) but was consistent with the slightly longer weaning to remating intervals in the RS line (7-8 (s.e. 0-7) v. 6-6 (s.e. 0-7) days, P = 0-22). Ovulation rate at second oestrus did not differ between the two lines (14-1 (s.e. 0-9) v. 14-3 (s.e. 0-5), for RS and AP gilts, respectively). The regression of mean accumulative productivity on time was in favour of the AP line (P = 0-05). These results suggest that reproductive performance is not impaired in gilts which have been selected to reach puberty at earlier ages, and productivity at a specific age may be enhanced.

Growth rate and age at boar exposure as factors influencing gilt puberty

“…Puberty induction at an early age (135-140 days of age) serves to identify the early responders and likely more fertile gilts during their breeding lifetime, since gilts selected for decreased age at puberty resulted in a higher percentage of sows farrowing after five parities (Holder et al, 1995). Patterson et al (2003) reported that out of 508 gilts stimulated with daily boar contact from 140 days of age, 75% of gilts were pubertal within 40 days of stimulation.…”

Influence of Gonadotrophin‐Induced First Oestrus on Gilt Fertility

“…The present study did not examine the association of early puberty with sow longevity, but other researchers have suggested that selection of gilts for reduced age at puberty improved their reproductive performance by increasing the proportion of animals retained in the herd through the first three parities (Patterson et al 2010) or the first six parities (Flowers 2011) and increased the average parity of culled sows at removal (Holder et al 1995). This should be an additional consideration in evaluating gilt selection programs.…”

“…) or the first six parities (Flowers ) and increased the average parity of culled sows at removal (Holder et al. ). This should be an additional consideration in evaluating gilt selection programs.…”

“…; Holder et al. ) with the corollary being that late‐developing gilts will be less fertile. Indeed, it has been clearly documented using intraherd comparisons in large population data surveys that gilts that were older at initial breeding were culled sooner with lifetime production of fewer pigs (Schukken et al.…”

“…It has been suggested that gilts that naturally achieve an early puberty may be relatively more fertile (Nelson et al 1990;Holder et al 1995) with the corollary being that late-developing gilts will be less fertile. Indeed, it has been clearly documented using intraherd comparisons in large population data surveys that gilts that were older at initial breeding were culled sooner with lifetime production of fewer pigs (Schukken et al 1994;Culbertson and Mabry 1995;Le Cozler et al 1998).…”