Search

In the frame of this paper it was researched the relationship between season and some reproductive parameters (oestrus length, pregnancy length and total born piglets) in primiparous and multiparous sows in terms of the photoperiodicity climate in Romania. The research was conducted on a crossbred Yorkshire sows (♀) × Landrace (♂) sow population and consisted of monitoring the oestrus duration, the gestation period and the number of total born piglets related to astronomical seasons: fall, winter, spring and summer. They were found seasonal influences characterized by a longer gestation length in autumn and spring seasons vs. summer and winter, with a difference of about one day between the seasons, and an annual average difference of about one day between primiparous and multiparous sows. Gestation length was inversely correlated with total born piglets. The oestrus length had an annual average of about 2.16 days in primiparous and 2.98 days in multiparous sows, with peak values in seasons of growing photoperiodicity and minimum values in seasons of decreasing photoperiodicity. [ABSTRACT FROM AUTHOR]

This study addressed the effect of breed on estrus length and estrous behavior by observing 20 Holstein-Friesian (HF) and 20 Norwegian Red (NRF) cows on an outdoor wood-chip pad through 1 estrous cycle (22 d). Detailed behavioral data were collected by continuous (24 h) video monitoring of all cows. Accurate estimation of duration of estrous periods, behavioral signs (sum per period and counts per hour), and duration and number of sexually active groups were reported through all stages of mount estrus (prestand, standing estrus, and poststand). These dependent variables were analyzed with a basic statistical model that included fixed effects for breed and lactation group. Other independent variables (milk yield, body condition score, and number of cows in standing estrus) were added to the basic model one by one and included in an expanded model if they had an effect on the respective dependent variables. Estrus duration was considerably shorter in HF compared with NRF cows for all the major periods: mount estrus (11.2 ± 3.0 vs 21.3 ± 2.7 h), standing estrus (7.1 ± 1.4 vs 11.7 ± 1.3 h), mounting period (6.9 ± 2.7 vs 18.2 ± 2.4 h), and mounted period (9.2 ± 2.8 vs 17.5 ± 2.6 h). Additionally, the NRF cows spent more time in sexually active groups (36.1 ± 4.0 vs 17.6 ± 4.8%) during standing estrus compared with HF cows. The NRF cows participated in a greater number of sexually active groups (9.6 ± 1.3 vs 5.5 ± 1.3) with longer average duration (0.42 ± 0.04 vs 0.20 ± 0.04 h) and continued to be more active in these groups through late stages of estrus (poststand) compared with the HF breed. Mounting activity differed between breeds as NRF mounted more times in total (46.3 ± 6.2 vs 18.1 ± 6.3) and per hour (2.6 ± 0.4 vs 1.5 ± 0.5) during mount estrus. In addition, NRF tended to express the primary estrous sign, standing when mounted, more often during standing estrus (32.4 ± 5.0 vs 18.5 ± 5.2). The HF initiated more unsuccessful mounts (1.6 ± 0.3 vs 0.6 ± 0.3) per hour than did NRF during mount estrus. A significant effect of milk yield was demonstrated only on this behavior. For other estrous signs, HF cows initiated chase-up (2.0 ± 0.5 vs 0.5 ± 0.4) and anogenital sniff (3.7 ± 0.6 vs 2.0 ± 0.5) more frequently (counts per hour), whereas NRF expressed more total head butt behavior (32.3 ± 4.7 vs 14.2 ± 4.8) during mount estrus. Body condition score had a significant effect on receptive behavior. Measures of estrus duration, sexually active group activity, and behavior related to estrus should be subjected to larger studies for improved heat detection and possible implementation in breeding programs. [ABSTRACT FROM AUTHOR]