Publications (19) View all
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Article: Factors affecting stillbirth and effects of stillbirth on subsequent lactation performance in a Holstein dairy herd in Isfahan
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ABSTRACT: The purposes of this study were to estimate the effects of risk factors on stillbirth parturition and evaluate the effects of stillbirth on lactation performance in Holstein dairy cows. Data were obtained from a dairy cattle herd located in Isfahan province, Iran. The logit of the probability of stillbirth was modeled using logistic regression and the effect of stillbirth on lactation performance was analyzed through mixed linear model using 12283 lactation records on 5201 cows. The results showed that 6% of the calves born die within 48 h of birth. The results of logistic regression analysis demonstrated that the frequency of stillbirth is significantly influenced (P<0.05) by calving year, parity number and calving difficulty. The stillbirth frequency was found to be significantly higher for first parity cows, (P<0.05). Also, calving difficulty was shown to be significantly associated with increased risk of stillbirth (P<0.05). Mixed linear model analysis results demonstrated that stillbirth significantly reduced milk and fat yield (P<0.05), but had no significant impact on milk fat percentage (P≥0.05). The 305-d milk and fat yields for cows with stillbirth were estimated to be 8274.17 ± 100.79 and 245.60 ± 3.7 kg compared to 8865.60 ± 88.16 and 259.36 ± 3.2 kg for cows that had a live calf, respectively.Iranian Journal of Veterinary Research ; 12(34). · 0.28 Impact Factor -
Article: Association between dry period length and lactation performance, lactation curve, calf birth weight, and dystocia in Holstein dairy cows in Iran.
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ABSTRACT: In this study, 65,971 lactations on 41,842 cows in 64 herds were used to determine the association between dry period length (DPL) and lactation performance, lactation curve, calf birth weight, and the incidence of calving difficulty during the subsequent parity in Holstein dairy cows in Iran. The length of the dry period was classified into 7 categories: 0 to 35 d, 36 to 50 d, 51 to 60 d, 61 to 70 d, 71 to 85 d, 86 to 110 d, and 111 to 160 d. Cows with the standard DPL (51 to 60 d) produced more 305-d milk, fat, and protein over the next lactation compared with those with shorter dry periods. Shorter dry periods (0 to 35 d and 36 to 50 d) were associated with lower initial milk yield, steeper inclining and declining slopes of the lactation curve, and higher milk persistency compared with dry period length of 51 to 60 d. Peak lactation was achieved later in cows with 0- to 35-d and 36- to 50-d dry period length than in those with dry period length of 51 to 60 d. We also observed a relationship between DPL and calf birth weight: smaller calf birth weight was recorded with a dry period of 51 to 60 d compared with longer dry periods. The incidence of calving difficulty did not differ in cows with 51- to 60-d dry period compared with cows with 0- to 35-d and 36- to 50-d dry periods. In conclusion, the results of this study did not support previous findings that suggested a shorter dry period could be beneficial to dairy production.Journal of Dairy Science 04/2013; · 2.56 Impact Factor -
Article: Oral exposure of broiler breeder hens to extra thyroxine modulates early adaptive immune responses in progeny chicks.
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ABSTRACT: Based on the findings of a recent study suggesting a decreased cold-induced ascites incidence in broiler progeny from hyperthyroid (HYPER) breeder hens, and a controversy on the effects of hyperthyroidism on immunocompetence, the present study was conducted to determine the probable adverse effect of induced maternal hyperthyroidism on immune function in progeny chicks. Breeder hens (n = 88) were randomly allotted to the control or HYPER groups and received common or thyroxine (T)-added (1 mg/L) water, respectively. The hens were artificially inseminated, and hatching eggs (n = 924) were incubated. Thereafter, the male hatchlings (n = 288) were reared for 42 d, and several cellular and humoral immune responses were evaluated at standard or low ambient temperature. Prevaccination antibody titers to Newcastle disease, infectious bronchitis, and infectious bursal disease virus were higher in HYPER chicks during 1 wk of age, although not different in their dams. For primary response to SRBC administered at 7 d of age, HYPER chicks recorded higher total, IgM (d 14), and IgG (d 21) anti-SRBC antibody titers. Higher cutaneous basophilic hypersensitivity response in HYPER chicks (d 10) was not observed at 35 d of age. Carbon clearance assay showed no difference, but in vitro lymphoproliferative response to concanavalin A was higher in 19-d-old HYPER chicks, independent of temperature treatment. An increase in lymphocyte percentage coincided with a decreased heterophil percentage and heterophil to lymphocyte ratio (d 14) in the HYPER group. The weight of lymphoid organs in progeny was not influenced by the oral exposure of dams to extra T. Independent of T treatment, cold exposure was generally associated with decreased immune functions at early stages. The data suggested that oral exposure of broiler breeder hens to 1 mg/L of T not only had no adverse effect on immune function, but also modulated early adaptive immune responses in progeny chicks for which the causal mechanisms remain to be unraveled.Poultry Science 04/2013; 92(4):1040-9. · 1.73 Impact Factor -
Article: Prestorage in ovo injection of biological buffers: An approach to improve hatchability in long-term stored eggs.
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ABSTRACT: A hypothesis was tested that the in ovo injection of biological buffers may reinforce the buffering capacity of albumen, thereby withstanding the increase in albumen pH during storage and improving hatchability and chick quality in long-term stored eggs. Hatching eggs (n = 2,420) were randomly assigned to 11 treatment groups (4 replicates of 55 eggs each) and injected (d 1) with distilled water, 25 or 50 mM HEPES (H and H), Bicine (B and B), Tris (T and T), and Bis-Tris-propane (BTP and BTP) solutions or were not injected (intact: control; or pricked with a needle: N). The eggs were then stored for 14 d during which the egg internal characteristics were evaluated at 1, 2, 3, 4, 5, 8, and 13 d of storage (n = 924 in total) and the remaining eggs (n = 1,496) were incubated. A decrease in albumen pH was found for H, H, B, and BTP groups from 2 through 5 d postinjection. Eggs receiving H, H, and B recorded a higher albumen index (at 13 d of storage) and Haugh unit (between 8 and 13 d of storage) compared with the control. Interestingly, the hatchability of fertile eggs was influenced by the treatment effect (P = 0.0001) where the eggs receiving H (88.3%), H (88.9%), B (88.4%), and BTP (87.6%) recorded higher values than that of control (82.1%), associated with a decreased early embryonic mortality rate (P < 0.0001). In ovo injection of Tris buffer, however, profoundly decreased the hatchability (47.2 and 29.0% for T and T, respectively) and percentage of first-grade chicks (67.5 and 63.6% for T and T, respectively) compared with the control (90.1%). In conclusion, prestorage in ovo injection of H, H, B, and BTP improved hatchability in long-term stored eggs in which a decreased albumen pH during the d 2 through 5 of storage period might be involved.Poultry Science 04/2013; 92(4):874-81. · 1.73 Impact Factor -
Article: Does preincubational in ovo injection of buffers or antioxidants improve the quality and hatchability in long-term stored eggs?
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ABSTRACT: A hypothesis was tested that providing buffer solutions or antioxidants during egg storage may help embryos in combating the harmful effect of longer holding periods. Hatching eggs were obtained from a breeder flock (35 wk) and stored for 13 d before setting. In experiment 1, the eggs were injected (d 4) with bicarbonate buffer solution (BBS) or PBS. For experiment 2, l-carnitine (LC), vitamin E (VE), and vitamin C (VC) were injected (d 7) at 3 different doses. The egg internal quality characteristics were evaluated at 2-d intervals after injection and the remaining eggs were incubated for 21 d under standard conditions. At 21 d, hatchability was recorded and unhatched eggs were broken open to assess the fertility and stage of embryonic mortality. No differences were noted in albumen pH due to using buffer solutions or antioxidants except for a decreased pH at 2 d postinjection of the high dose of VC (75 mg). In ovo injection of BBS increased the albumen index and Haugh unit at d 6 postinjection; however, the response to PBS was not different from that in the control group. In ovo injection of antioxidants did not influence the albumen index, Haugh unit, and yolk index; however, the yolk percentage was partly affected. Irrespective of the dosage, hatchability was greatly decreased following in ovo injection of buffers or antioxidants (as low as 4.3 vs. 87.5% in control), with the highest mortality percentage recorded at early embryonic stages (d 0 to 6). Data suggested that, despite improvement in certain egg internal qualities, preincubational in ovo injection of BBS, PBS, LC, VE, or VC was associated with a profoundly decreased hatchability for which the underlying mechanism(s) remain(s) to be clarified.Poultry Science 11/2012; 91(11):2970-6. · 1.73 Impact Factor
