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

Abstract

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 (5^th-95^th percentile range 429-840), while the age at first calving was 802 days (5^th-95^th percentile range 708-1168). The median pregnancy proportion at first insemination was 40% (5^th-95^th 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 (5^th-95^th percentile range 16-408). The calving-to-conception interval was 101 day (5^th-95^th percentile range 36-506). Finally, the calving interval was 385 days (5^th-95^th 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.

Figure 1

Distribution of selected dairy farms in Una-Sana Canton, BH.

Figure 2

(a) Scheme of the recording of reproductive events in selected farms in Una-Sana Canton; (b) the calculation of reproductive indicators from available farm records. AI, artificial insemination; AFI, age at first insemination; AFC, age at first calving; NSP, number of services per pregnancy; ISI, interservice intervals; CFI, calving to first insemination interval; CCI, calving to conception interval; CI, calving interval.

Figure 3

Distribution of the age-at-first-insemination (artificial or natural breeding) and the age-at-first-calving in heifers among selected dairy farms in Una-Sana Canton, BH. Some investigated farms had heifers with AFI and AFC far removed from the mass of farm data, indicating certain reproductive problems. Those heifers are referred to farm outliers (dots in the graph).

Figure 4

The pregnancy proportion expressed as (a) the pregnancy proportion for heifers at the first insemination service and (b) the population-level cumulative pregnancy rate at day-60, day-80, day-100, and day-120 after the previous calving in the selected dairy farms in Una-Sana Canton, BH.

Figure 5

The number of services (artificial insemination and natural breeding) per pregnancy expressed as (a) the percentage of successful services distributed by the number of attempts and (b) the mean number of services per pregnancy distributed by the dairy farm in the selected area of Una-Sana Canton, BH.

Figure 6

Interservice intervals histogram. Repeat breeding services recorded and compiled at the population level showed that 68.7% of returns to the oestrus occurred in 18 to 24 days period. Considering good oestrus detection, the target is set on 55% as described in [15].