ABSTRACT
The present investigation recorded that the average litter size was 2.03 per doe and the prolificacy rate being 202.92%. The result indicates that the litter size proportion for single, twin and triplet were 28.3%, 40.4% and 31.3% respectively. There was a tendency of increasing body weight with higher litter size and such variation was highly significant (P<0.01). The result revealed that the overall mean age of first estrus was 209.08±2.06 days. Maximum age of first conception was 226.18±5.39 days when the animal gave single birth and the minimum AC was 216.65±4.9 days when it produced triplet indicating that failure of conception was more in single bearing does. Service period were recorded to very significantly (P<0.01) among different litter bearing groups, the highest value was observed in triplet producing does (80.88±4.68 days). This is an important finding to understand that, less Age of Puberty (AP), Age at 1stConception (AC), Days Open (DO) & Kidding Interval (KI) has prominent benefit for multiple foetuses and thus achieving economic benefit.
ABSTRACT
It is widely accepted that selection for high milk yield in dairy cows has negatively affected their reproductive performance. After calving, dairy cows experience a nutritional imbalance due to an asynchrony in the occurrence of the lactation and dry matter intake peaks. In the tropics, this situation is exacerbated due to poor quality and/ or availability of the diet. A study was carried out to describe the nutritional and reproductive behavior of two-to-four parturition crossbred cows (Gyr (Bos indicus) x Holstein (Bos taurus)) divided in two groups according to their calving to first service interval (CFSI): Group 1: ≤50 days CFSI, n=7; Group 2: ≥50 days CFSI, n=8. Animals were grazing in an intensive silvopastoral system (ISS) based on Leucaena leucocephala and Cynodon plectostachyus and also received protein, energy and mineral supplementation. Dry matter (DMI) and nutrient intake were individually estimated and correlations between reproductive and nutritional parameters were performed. Additionally, serum progesterone concentration was monitored. Group 2 had greater forage and total DMI and milk production than Group 1 (P<0.05). Hence, Group 2 had greater nutrient intake from forages than Group 1 (P<0.05). Group 1 had a positive nutritional balance and an optimum reproductive performance compared to Group 2, which had a negative energy balance and lengthier days with open intervals (P<0.05). It was corroborated that protein and energy are required in adequate levels, to ensure that uterus undergoes involution correctly and ovarian activity starts soon in the postpartum period.(AU)
É amplamente aceito que a seleção para alta produção de leite em vacas leiteiras tem interferido no seu desempenho reprodutivo. Depois do parto, um extraordinário desafio nutritivo é experimentado pelas vacas leiteiras, devido a uma assincronia entre a ocorrência do pico de lactação e a do pico de consumo de matéria seca. Este estudo foi realizado para descrever o comportamento reprodutivo de vacas mestiças de dois a quatro partos (Gyr (Bos indicus) x Holstein (Bos taurus)), divididos em dois grupos, de acordo com seu intervalo parto ao primeiro serviço (IPPS): grupo 1: ≤ 50 dias IPPS, n = 7; grupo 2: ≥50 IPPS dias, n = 8. Os animais pastaram em um sistema silvipastoril intensivo (SSI), com base em Leucaena leucocephala e Cynodon plectostachyus, e receberam também suplementação de proteína, energia e mineral. Matéria seca (CMS) e ingestão de nutrientes foram estimadas individualmente e correlações entre parâmetros reprodutivos e nutricionais foram realizadas. Além disso, a concentração de progesterona em soro foi monitorizada. Vacas do grupo 2 apresentaram maior ingestão de forragem, de dieta total e de produção total de leite do que vacas do grupo 1 (P<0,05). Dessa forma, vacas do grupo 2 apresentaram maior consumo de nutrientes de forrageiras do que os animais do grupo 1 (P<0,05). Vacas do grupo 1 tinham um equilíbrio nutricional positivo e um ótimo desempenho reprodutivo em relação ao grupo 2, que teve um balanço energético negativo e mais longos intervalos de dias abertos (P<0,05). Foi corroborado que a proteína e a energia são necessárias em níveis adequados, assim o útero sofre involução corretamente e a atividade ovariana começa logo no período pós-parto.(AU)
Subject(s)
Animals , Female , Cattle , Animal Feed/analysis , Cynodon , Dietary Proteins/analysis , Energy Metabolism , Fabaceae , Animal Nutritional Physiological Phenomena , Reproductive Physiological PhenomenaABSTRACT
Background: high environmental temperature coupled with high humidity can result in reproductive failure in dairy cattle, with a drastic reduction in reproductive efficiency of dairy herds. Objective: to study the effect of high environmental temperature on reproduction performance of Holstein cows treated with recombinant bovine somatotropin (rbST) throughout lactation in an arid environment. Methods: reproductive variables (n=18,037 services) from a large dairy herd were evaluated with respect to the maximum temperaturehumidity index (THI) prior to breeding, on the breeding day, and after breeding. The GENMOD procedure of SAS was used to assess the effect of THI and month of breeding on pregnancy by artificial insemination (P/AI). Results: increased THI from ≤ 70 to ≥ 95 units was associated with a decrease in P/AI from 47% to 26%. P/AI for cows inseminated on extremely hot days (THI= 85 to 90) preceded by cooler temperatures was six percent points higher than cows subjected to high temperatures before breeding. P/AI was higher (p<0.05) from January to March (39% to 41%) compared with the rest of the year (27% to 35%). The average number of inseminations per pregnancy was higher (p<0.05) from May to July (3.0 to 3.4) compared to other months (2.1 to 3.0). Conclusions: in this particular hot-arid environment (maximum temperature >38 ºC most of the year, and 230 mm mean annual rainfall), heat stress shortly before or after breeding severely compromises the breeding success of high yielding Holstein cows.
Antecedentes: la asociación entre temperaturas ambientales elevadas y alta humedad conduce a fallas reproductivas, disminuyendo la fertilidad de hatos lecheros. Objetivo: determinar el efecto de temperaturas ambientales elevadas sobre el comportamiento reproductivo de vacas Holstein mantenidas en un ambiente árido y cálido y tratadas con hormona del crecimiento (rbST) durante toda la lactancia. Métodos: las variables reproductivas (n=18037 servicios) de una explotación comercial fueron evaluadas con respecto al máximo índice temperatura humedad (THI) antes, durante y después de la inseminación de las vacas. El procedimiento GENMOD de SAS se utilizó para determinar el efecto del THI y el mes de inseminación sobre las tasas de preñez (P/AI). Resultados: el incremento del THI de ≤ 70 a ≥ 95 unidades se asoció con una disminución en el P/AI de 47% a 26%. El P/AI para las vacas inseminadas en días con un ITH de 85 a 90, pero con temperaturas menos cálidas antes de la inseminación, fue de seis puntos porcentuales más altos (30% vs. 36%) que en las vacas expuestas a ITH más altos antes de la inseminación. El P/AI fue mayor (p<0,05) de enero a marzo (39% a 41%) comparado con el resto de los meses del año (27-35%). El número de servicios por preñez fue mayor (p<0,05) de mayo a julio (3,0 a 3,4) que en los otros meses del año (2,1 a 3,0). Conclusiones: en este ambiente extremadamente caliente (temperaturas máximas > 38 °C la mayor parte del año) y árido (promedio de precipitación anual de 230 mm), el estrés calórico poco antes o después de la inseminación disminuye drásticamente las probabilidades de establecer una gestación en vacas de alta producción de leche.
Antecedentes: a associação entre alta temperatura e umidade no ambiente pode originar problemas reprodutivos, diminuindo o índice de fertilidade dos rebanhos leiteiros. Objetivo: avaliar o efeito da elevada temperatura ambiente sobre o desempenho reprodutivo de vacas da raça Holandês mantidas num ambiente quente e árido, as quais foram tratadas com somatotropina bovina recombinante (rBST) durante toda a lactação. Métodos: as variáveis reprodutivas (n = 18037 serviços) de um rebanho leiteiro foram avaliadas em relação ao máximo índice de temperatura-umidade (THI), antes, durante e depois da inseminação artificial das vacas. O procedimento GENMOD do SAS foi usado para avaliar o efeito do THI e do mês de reprodução sobre as taxas de gestação por inseminação artificial (P/AI). Resultados: o aumento do THI de ≤ 70 para ≥ 95 unidades foi associado com a diminuição no índice P/AI, de 47% a 26%. Em dias com THI de 85 - 90, mas com menor temperatura ambiental antes da inseminação, o índice P/AI foi 6% maior do que nas vacas expostas a superior THI. O índice P/AI foi maior (p<0,05) de janeiro a março (39% a 41%), em comparação aos outros meses do ano (27 a 35%). O número médio de inseminações por prenhez foi superior (p<0,05) de maio a julho (3,0 a 3,4) quando comparado aos outros meses do ano (2,1 a 3,0). Conclusões: em ambiente quente e seco (temperaturas máximas > 38°C a maior parte do ano, média de precipitação anual de 230 mm) o estresse térmico antes e depois da inseminação reduz drasticamente a possibilidade de estabelecer uma gestação em vacas de alta produção de leite.
ABSTRACT
The records of 63,406 calvings of Siboney dairy cows (5/8 Holstein 3/8 Cuban Zebu) were used to estimate the components of covariance of the days open (DO). Five models were used: of repeatability; univariate; bivariate; of random regression with Legendre polynomials and the parity number as predicting variable; and a model of random regression with Legendre polynomials and heterogeneity of the residual variance. The heritability obtained with the univariate model was 0.09 in the first calving and decreased to 0.05 in the fifth. A higher estimate of heritability (0.12) was obtained with the repeatability model. When the model of random regression with heterogeneity of the residual variance was used, the heritability was higher than the values estimated with the previous models. The genetic correlations among the DO in different calvings, estimated with the models of random regression with and without heterogeneity of the residual variance, were close to 1.0. It is concluded that the estimates of heritability increased with the use of the random regression models. The genetic correlations among the DO of different calvings indicated that in the first three, the DO are regulated for the most part by the same genes.
Os registros de 63.406 partos de vacas Siboney (5/8 Holstein 3/8 Cebu de Cuba) foram utilizados para estimar os componentes de (co)variância de dias vazios (DV). Utilizaram-se cinco modelos: de repetitividade; univariado; bivariado; de regressão aleatória com polinômios de Legendre e número de partos como variável preditiva; e de regressão aleatória com polinômios de Legendre e heterogeneidade da variância residual. A herdabilidade obtida com o modelo univariado foi de 0,09 no primeiro e diminuiu a 0,05 no quinto parto. Uma estimativa de herdabilidade mais alta (0,12) foi obtida com o modelo de repetitividade. Quando foi usado o modelo de regressão aleatória com heterogeneidade da variância residual a herdabilidade foi superior aos valores estimados com os modelos anteriores. As correlações genéticas entre os DV em distintos partos, estimadas com os modelos de regressão aleatória com e sem heterogeneidade da variância residual, foram próximos a 1,0. Concluiu-se que as estimativas de herdabilidade foram incrementadas com o uso dos modelos de regressão aleatória. As correlações genéticas entre os DV de diferentes partos indicaram que, nos três primeiros, os DV são regulados na sua maior proporção pelos mesmos genes.
Subject(s)
Animals , Heredity/genetics , Postpartum Period/physiology , Cattle , Genetic Variation , Models, TheoreticalABSTRACT
Para evaluar el efecto de los días postparto al tratamiento (DPP), predominio racial (PR), número de partos (NP) y época del año (E) sobre la ciclicidad y fertilidad de vacas mestizas en anestro tratadas con esponjas intravaginales (EI) impregnadas con Medroxi-acetato progesterona (MAP) más una inyección de eCG y PGF2a; se condujo un experimento en una finca ubicada en un bosque húmedo-tropical en el municipio Machiques de Perijá-Zulia, Venezuela. Se seleccionaron 72 vacas mestizas Bos taurus × Bos indicus primíparas (47) y multíparas (25) entre 45 y 108 días postparto (DPP) y condición corporal (CC) entre 3 y 3,5. Las vacas recibieron el siguiente esquema hormonal: Día 0: inserción de la EI, inyección de 5 mg de 17b-Estradiol y 50 mg de MAP im; Día 6: 500 UI de eCG y 25 mg de PGF2a im; Día 8: retiro de la EI; Día 9: 1 mg de 17b-Estradiol im. Un grupo fue tratado antes de los 70 DPP (MAP < 70DPP; n = 25) y otro después de los 70 DPP (MAP > 70DPP; n = 47). Se estudió la tasa de sincronización (TS), fertilidad al primer servicio (F), fertilidad global (FG), Intervalo Tratamiento-Concepción (ITC), Intervalo Parto-Concepción (IPC) y periodo de sincronización (PS). Las variables TS, F, y FG se analizaron con PROC LOGISTIC, SAS; mientras que ITC, IPC y PS con PROC GLM, SAS. No se encontró efectos del PR y NP sobre la TS, F, FG, ITC, IPC y PS. Las vacas con PR Bos indicus presentaron mayor F y FG en el grupo MAP < 70DPP comparada con MAP > 70DPP (F: 81,8 vs 43,7%; FG: 84,6 vs 45,5%). La TS fue mayor en las vacas tratadas en la época lluviosa comparada con la seca (96,4 vs 69,8%). La F solo fue mayor en la época lluviosa cuando las vacas fueron tratadas antes de 70DPP vs MAP > 70DPP (87,5 vs 42,1%). El PS fue menor en la época seca (36,9 h) vs la época lluviosa (48,8 h). El IPC fue menor en MAP < 70DPP (95,8 días) comparado con MAP > 70DPP (148,3 días). En conclusión, los días postparto al momento de la aplicación de la EI fue el factor que más ...
An experiment was done to evaluate the effect of postpartum interval to treatment (DPP) breed (PR), number of calving (NP) and season (E) on ciclicity and fertility of anestrous crossbred cows treated with intravaginal sponges (EI) impregnated with progesterone medroxi acetate (MAP) plus im injection of eCG and PGF2a. The study was conducted in a farm located in a tropical rainforest in Machiques de Perijá, Venezuela. Seventy two primiparous (47) and multiparous (25) Bos taurus × Bos indicus crossbred cows, between 45 and 108 days postpartum (DPP) and body condition (CC) between 3.0 and 3.5. Cows were treated as follows: MAP; Day 0, EI insertion + 5 mg 17b-Estradiol and 50 mg MAP im; Day 6, 500 IU eCG and 25 mg PGF2a im; day 8 EI removed; day 9 1 mg 17b-Estradiol im. One group was treated before 70 DPP (MAP < 70DPP; n = 25) and another after 70 DPP (MAP > 70DPP; n = 47). Studied variables were: Synchronization rate (TS), first service conception rate (F), total pregnancy rate (FG), treatment to conception interval (ITC), calving to conception interval (IPC) and synchronization period (PS). Variables TS, F, and FG were analyzed with PROC LOGISTIC, SAS, while ITC, IPC and PS were analyzed with the PROC GLM, option SAS. Variables TS, F, FG, ITC, IPC and PS were not affected by PR and NP. Cows predominantly Bos indicus in MAP < 70DPP had greater (P < 0.05) F and FG than those in MAP > 70DPP (F: 81.8 vs 43.7%; FG: 84.6 vs 45.5%). The TS was greater (P < 0.01) in cows treated during the rainy season than those treated during the dry season (96.4 vs 69.8%). During the rainy season, cows in MAP < 70DPP had greater (P < 0.01) F than did those in MAP > 70DPP (87.5 vs 42.1%, respectively). The PS was shorter (P < 0.01) during the dry season (36.9 h) vs the rainy season (48.8 h). The IPC was shorter (P < 0.01) in MAP < 70DPP (95.8 days) compared to MAP > 70DPP (148.3 days). In conclusion, days to EI insertion after parturition was the most important ...