Impact of frequency of milking on milk yield and fertility of Holstein cows undergoing extended lactations due to failure to conceive

The objective of this observational study was to determine the effect of two (2x) compared to three (3x) times a day milking in Holstein cows undergoing lactations ≥600 d on milk production and reproductive performance. Two large adjacent commercial dairy herds with similar size, facilities, and management in a hot area of northern Mexico (25° N) were used. Cows in one herd (n= 214) were milked two times a day (2x), the other herd was milked three times a day (3x; n=245) and both groups were milked for at least 600 days. For cows in first lactation, total milk yield did not differ between 3x and 2x cows (19796 ± 3354 vs. 19269 ± 3652 kg; p > 0.10) in lactations with an average of 696 and 650 days in milk (DIM), respectively. Multiparous 3x cows produced more total milk days than 2x cows (20942 ± 3920 vs. 18910 ± 2632 kg; p < 0.01) with greater (p < 0.01) DIM for 3x (685 ± 117 days) than 2x (631 ± 88 days) cows. Lactation persistence was greater (p < 0.05) in 2x (62 ± 9%) than 3x (60 ± 10%) cows. Overall conception rate (CR) did not differ between 2x and 3x cows (53.3% vs. 49.8%) but 3x cows required one more service (p < 0.01) to get pregnant than 2x animals. Given that average milk yield throughout the complete lactation did not differ between 2x (29.8 ± 2.0 kg) and 3x (29.3 ± 2.9 kg) cows, it was concluded that two-times-a-day milking is equally effective as three-times-a-day milking to attain acceptable milk yield in lactations over 600 days. However, reproductive performance based on first-service CR and services per pregnancy was negatively affected by three-times-a-day milking.

Reproductive Performance in a Selected Sample of Dairy Farms in Una-Sana Canton, Bosnia and Herzegovina

Background. The production of milk and dairy products and their placement on the market represent a constant profit for the farmers/producers in Bosnia and Herzegovina (BH). The profitable operation of the dairy farms is influenced by the reproductive performance of the lactating animals. This study assessed individual animal reproductive characteristics in selected dairy farms and described their reproductive performance indicators. Results. The median age at first insemination was 493 days (5th–95th percentile range 429–840), while the age at first calving was 802 days (5th–95th percentile range 708–1168). The median pregnancy proportion at first insemination was 40% (5th–95th percentile range 17–62), while the cumulative pregnancy rate calculated at day-60, day-80, day-100, and day-120 showed that approximately 64% of all pregnancies happened before day-120. The calculated interservice intervals showed that approximately 69% of the repeat breeding animals came back to the oestrus in the period of 18 to 24 days. This is an indication of very good oestrus detection in selected dairy farms. The mean number of services per pregnancy was 2.61 (range 1–12). The median calving-to-first-insemination interval was 62.5 days (5th–95th percentile range 16–408). The calving-to-conception interval was 101 day (5th–95th percentile range 36–506). Finally, the calving interval was 385 days (5th–95th percentile range 329–773). Conclusions. There is a need for an organised, regular, and more comprehensive recording system for the reproduction of dairy cattle among dairy farms in Una-Sana Canton. The calculated reproductive measures indicated an undulant trend in reproductive performance among selected dairy farms in Una-Sana Canton. Knowing the apparent reproductive indicators described in this study, the farmers and veterinary authorities may identify and correct areas in their management that contribute to the reproductive underperformance.

Genetic and phenotypic parameter on fertility traits of Red Chittagong Cattle in Bangladesh

The fertility of Red Chittagong Cattle (RCC) of Bangladesh was studied using data from 122 animals from four herds. The least squares means of female fertility traits were 1.4 ± 0.1, 72.6 ± 3.6% and 85.0 ± 2.0%, respectively, for number of services per pregnancy, first service pregnancy rate and overall pregnancy rate. The least squares mean of non-return rate to first service of bull was 58.7 ± 5.1%. The factor having a significant effect on female fertility was herd, while parity had no effect. Herd and parity of dam, season of service and sire had no effect on non-return rate to first service of bull. The heritability of fertility traits were very low: values were 0.07 ± 0.04, 0.03 ± 0.04, 0.05 ± 0.04 and 0, respectively, for number of services per pregnancy, first service pregnancy rate, overall pregnancy rate and non-return rate to first service of bull. The corresponding repeatability values were 0.18 ± 0.08, 0.08 ± 0.07, 0.13 ± 0.08 and -0.07 ± 0.02, respectively. This study reveals the fertility to be good. However, better reproductive management may enhance the overall herd fertility of RCC. DOI: http://dx.doi.org/10.3329/bvet.v29i2.14347 Bangl. vet. 2012. Vol. 29, No. 2, 78-89

Comparative performance of different regional native sheep in Bangladesh

This study was undertaken to investigate the performance of native sheep in Bangladesh. Data were collected during 2004-2010 from sheep of the Barind, Jamuna and Coastal areas. The phenotypic characteristics did not differ significantly, but ears were shorter in Barind than in Jamuna and Coastal sheep. The coat colour was 45% white, 26% brown, 24% white brown and 3% black brown in Barind and Jamuna sheep, but white (70%) and white brown (30%) in Coastal sheep. Differences were not significant for age at first heat, age at first pregnancy and age at first lambing. Days open and post-partum ewe weight were significantly (P<0.01) different. Onset of post-partum heat, lambing interval, gestation length, number of services per pregnancy, litter size and placental weight did not differ significantly. Birth weight was significantly (P<0.05) higher in Coastal sheep than in Barind and Jamuna. Higher (P<0.05) wool yield was obtained in Coastal sheep and in the summer. Though the wool was coarse and hairy, wool from Coastal sheep had more (P<0.05) bends per inch, and was finer. Diarrhoea, pneumonia in lambs and skin diseases were the most common diseases in all sheep. Though sheep from the different areas had similar performance, better reproductive performance was obtained in the Barind sheep.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10692Bangl. vet. 2011. Vol. 28, No. 2, 85 – 94

Milk production and reproductive performance of cows induced into lactation and treated with bovine somatotropin

Milk production and reproductive performance of pluriparous dairy cows was compared for cows whose lactations were induced by hormonal treatment or followed natural calving. The study was conducted on 179 high-yielding dairy cows in a large dairy operation in a hot arid environment of northern Mexico, where bovine somatotropin (bST) was routinely used in all cows. To induce lactation, 98 cows that had previously failed to become pregnant were treated with 500 mg bST on days 1, 8 and 21. From days 2 to 8, cows were treated with oestradiol cypionate (0·30 mg/kg live weight (LW) per day) and progesterone (0·28 mg/kg LW per day). From days 9 to 15, oestradiol cypionate alone was given. PGF2α was given on day 16. Nothing was administered on days 17 and 18, and 15 mg flumetasone was administered from days 19 to 21. Lactation was induced successfully in all 98 cows subjected to the hormone treatment. All cows received 500 mg bST every 14 days throughout lactation from 63±7 days after lactation had started. Cows with induced lactations produced less (P<0·01) milk per 305-day lactation (9599±1387 kg) than controls (12 302±1245 kg). Proportion of cows pregnant was similar in induced cows and non-treated cows (71 v. 75%). Induction of lactation was associated with increased numbers of services per pregnancy (5·8±4·0 v. 4·22±2·98; P<0·01) compared with controls; however, impaired reproduction might not necessarily have been related to the hormonal treatment to induce lactation, but due to the nature of the cows utilized for this treatment group. This protocol can be used on dairy farms where bST treatment and prolonged steroid administration of dairy cows is legally permitted.

Fertility and parasitic infestation of Red Chittagong cattle

Fertility of Red Chittagong bulls (RCB) using Non-Return Rate (NRR), reproductive efficiency of Red Chittagong cows (RCC) using pregnancy rate and number of services per pregnancy and parasitic infestation of two different ages and sexes were studied. The NRR ranged from 53.1% to 70.6% with an overall mean of 63.9%. Overall pregnancy rate was 65.8% and about 1.4 services were required per pregnancy. Overall 47.7% animals were infested with parasites. Five species of parasites were detected in the faeces: Balantidium coli (40%), Paramphistomum spp (47.7%), Fasciola spp (5.8%), Coccidia spp (4.5%), and Moniezia spp (1.9%). The prevalence of parasites in animals over four years age was higher (P<0.05) than in animals below four years of age: the prevalence was higher in female than in male hosts (P>0.05). DOI: 10.3329/bvet.v27i2.7557 Bangl. vet. 2010. Vol. 27, No. 2, 74-81

Impact of urea-based diets on production of Red Chittagong Cattle

The production traits of Red Chittagong Cattle (RCC) were studied using two diets: A [Urea-molasses-rice straw (UMRS), Green Grass and Concentrate] and B [Rice straw, Green Grass and Concentrate]. In cows fed diets A and B, birth weights of calves were 15.2 and 14.1 kg (P<0.05), daily milk yield 2.0 and 2.0 kg (P>0.05), lactation length 254.8 and 247.1 days (P>0.05), age at first oestrus 28.4 and 25.6 months (P<0.05), number of services per pregnancy 1.6 and 2.5 (P<0.05), onset of postpartum oestrus 141.3 and 109.3 days (P<0.05), calving interval 14.2 and 13.3 months (P<0.05), semen volume per ejaculation 3.0 and 3.7 ml (P<0.05), mass activity of sperm 58.6 and 68.4% (P<0.01) and sperm concentration 709.1 and 1289.0 million/ml (P<0.01), respectively. DOI: 10.3329/bvet.v26i2.4954 Bangl. vet. 2009. Vol. 26, No. 2, 74-79

Effects of nutrition on production and reproduction of dairy cows in Bangladesh

Sixty-eight cows in group A were fed 63.9 megajoules (MJ)/day, 66 in B were fed52.9, and 66 in C were fed 51.1 MJ/day. The mean (± SD) services per pregnancy of cowsin groups A, B and C were 1.7 ± 0.7, 1.9 ± 0.6 and 2.5 ± 0.9, respectively. The mean calvingto 1stfirst service intervals were 158.1 ± 51.5, 171.0 ± 59.0 and 200.0 ± 50.3 days,respectively. The mean milk yields were 5.8 ± 2.6, 4.5 ± 1.9 and 4.3 ± 1.9 litres/ day,respectively. Pregnancy rate was significantly (P<0.05) affected by breed, parity, age,body condition score (BCS) and body weight of cows. Breed and parity had no significanteffect on pregnancy rate. Age, BCS and body weight had significant (P<0.05) affect onpregnancy rate.(Bangl. vet. 2010. Vol. 27, No. 1, 8 – 17)DOI: 10.3329/bvet.v27i1.5910