The effect of calving season on reproductive performance of Jersey cows

Abstract

Dairy records, containing 1269 lactation record of 462 Jersey dairy cows collected over 16 years, from an agricultural state farm were used. Data for reproductive performance of cows were also collected. Means of the herd for lactation milk yield, calving interval, days open, interval from calving to the first insemination, lactation length, gestation length and dry period were 3195.7±20.2 kg, 366.6±1.7 d, 92.9±1.6 d, 78.0±1.3 d, 301.7±1.1 d, 275.2±0.2 d and 69.3±0.8 d, respectively. The effect of calving season (winter, spring, summer and autumn) on reproductive performance for high, low and moderate milk-yield cows was investigated. Calving season affected the days from calving to first insemination in high and moderate yielding cows (P<0.001) while didn't affect low yielding cows. In summer, days open in high yielding cows were 35 days longer compared to winter season (P<0.001) as observed for moderate yielding cows (P<0.01). In high yielding cows, calving interval was 18 days longer in spring compared to winter calving season. Calving season also affected the first service conception rate in high yielding cows (P<0.05). Services per conception in autumn were lower than the other seasons (P<0.001). In conclusion, high yielding dairy cows need more attention in summer season with respect to body condition score, dietary energy: protein ratio, uterus health and elimination of heat stress, to get more profit in dairy farm.

Nonparametric and Semi-parametric Survival methods for Assessing days Open and Conception rates of Lactating cows

“…These findings have confirmed the estimates of survival functions generated by the Kaplan-Meier method (Table 4), where the medians of days open for all seasons were shorter than those of summer. These findings agreed with the reports of other researchers (Farin et al, 1994;Muller et al, 2014;Soydan and Kuran, 2017) who concluded that high temperatures and heat stress adversely affect the reproductive efficiency of dairy cattle. In practice, it can be concluded that, cows calved in winter had a 36.7 % higher hazard of conception than cows calved in summer.…”

“…The results revealed that cows calved in winter months had shorter DO than those calved in summer and hot months. This finding is in consistence with those reported by other studies (Muller et al, 2014;Soydan and Kuran, 2017) who revealed that cows that calved in winter months had more chance to become pregnant than those calved in summer. Jordan (2003) reported that when dairy cows are exposed to heat stress, their reproductive performance declines along with uncontrolled estrus.…”

Association between milk urea nitrogen and first service conception in smallholder dairy farms under heat and humidity stress

“…We deduce that there was low protein intake in some farms from our low mean PE ratio and that protein deficiency, especially in early lactation, had an impact on the reproductive efficiency [16,17]. Prolonged days open, increased number of services per conception, and decreased pregnancy rate have been reported problems associated with inadequate protein intake elsewhere [16,18].…”

“…Moreover, summer months have been shown to lead to reproductive hormone disturbance, deteriorated oocyte development, and early fetal death [19]. In addition to these direct effects of high temperature on reproduction, summer months have also been shown to indirectly influence reproduction by low protein and digestibility in the pasture and decreased feed intake, resulting in a negative change in energy balance [18,22]. Our results slightly differed from these seasonal effects on FSC during 4 months after calving; there was no significant difference in FSC between the rainy season and summer season in our data.…”

Efeito De Estratégias Anti Luteolíticas Sobre a Fertilidade De Novilhas De Corte / Effect of Antiluteolytic Strategies to Improve Fertility in Heifers

“…A lucratividade do sistema de produção de bovinos de corte está intimamente relacionada com a eficiência reprodutiva do rebanho. No Brasil, ainda são registradas baixas taxas de eficiência reprodutiva, devido a mortalidade embrionárias, que promovem longos intervalos de partos e baixa lucratividade aos sistemas de produção de carne bovina (Soydan & Kuran, 2017;Silva et al 2019).…”