Long Term Administration of Exogenous Oxytocin: Effects on Pregnancy Rate, and Embryonic and Fetal Losses in Nili-Ravi Buffaloes

Abstract

It is a common perception among dairy farmers in Pakistan that oxytocin (OT) injection negatively effects on buffalo reproduction parameters. Therefore, current study was conducted to investigate the outcomes of OT on numbers of AI per conception, pregnancy rate, embryonic and fetal losses (EFL). For this purpose, Nili-Ravi buffaloes (n=23) were randomly divided into three groups, G1; n=7 (control), G2; n=8 (low dose 10 i.u.) and G3; n=8 (high dose 30 i.u.). The OT injection was given twice daily at morning and evening milking until 154 days post calving. At heat, AI was performed. Ultrasonography and blood sampling were done on days 30, 45 and 60 post AI to monitor pregnancy and progesterone, respectively. Results showed significant (P≤0.05) increase of AI services per conception in G2 & G3 as compared to G1. Furthermore, results revealed that chances of the animals to become pregnant were 0.227 and 0.094 times in low (G2) and high doses (G3) in comparison to control (G1), respectively, and was lower significantly (P≤0.05). Similarly, pregnancy rate was remained unaffected and was non-significant (P>0.05) on day 45 vs day 30. However, it was significantly (P≤0.05) lower on day 60 vs day 30. Overall, pregnancy rate was decreased (P≤0.05) in oxytocin treatments comparable to control. Parity and days in milk had no significant effect on pregnancy rate among treatments (G1, G2 and G3), respectively. Moreover, EFL losses were non-significant (P>0.05) among treatments but losses trend was more in G2 & G3 parallel to G1. Result also showed non-significant (P>0.05) decrease in P4 on days 30 and 45 while significant (P≤0.05) on day 60 in G2 & G3 as compared to G1 among treatment groups. It may be concluded that long term OT injections of both low and high doses cause significant losses in terms of increase in AI services per conception and decrease pregnancy rate with higher EFL in Nili-Ravi buffaloes.

The Role of Oxytocin in Domestic Animal’s Maternal Care: Parturition, Bonding, and Lactation

“…Some of the reported adverse effects are changes in the physicochemical analysis of the milk and impacts on the reproductive health of females. For example, the effect of long-term administration of OXT on pregnancy rates of 23 Nili Ravi buffaloes was studied by Murtaza et al [ 169 ]. The animals received two doses of OXT twice daily (10 and 30 IU) for 154 days post-calving.…”

“…The animals received two doses of OXT twice daily (10 and 30 IU) for 154 days post-calving. In general, in animals receiving the hormone, pregnancy rates decreased ( p < 0.05), more artificial insemination (AI) per conception was required, and the presentation of fetal losses increased in comparison to animals not receiving OXT [ 169 ]. A similar finding was reported in 430 cows (Holstein Friesian and Swedish-Red) by Gümen et al [ 170 ].…”

“…Regarding the exogenous management of OXT, although it is used to reduce expulsion times, improve milk yield and ejection, and reduce newborn mortality [ 47 , 48 , 49 ], it is a controversial practice because of the potential adverse effects on dairy animals [ 5 ], such as, e.g., intervals between calving and retracements in ovulation [ 169 ], and productive effects (impact on milk composition) [ 23 ]. On the other hand, it is also necessary to investigate positive stimuli that have been promising, such as the use of brushes, massage [ 176 ], music [ 163 ], synthetic analogues of maternal appeasing pheromones [ 177 ], and the acquisition of a pre-calving milking routine [ 153 , 154 ] to improve dairy cow performance and/or milk parameters.…”